Pratique École

Hautes Des

Études

PhD William Berthon

MD Olivier Dutour

PhD György Pálfi

PhD Hélène Coqueugniot

PhD László Révész

Bioarchaeological Analysis of the Mounted Archers from the Hungarian Conquest Period (10th Century): Horse Riding and Activity-Related Skeletal Changes

This dissertation is dedicated to my mother.

Tout ce qui est mort comme fait, est vivant comme enseignement.

ACKNOWLEDGMENTS

First of all, I would like to sincerely thank the members of the defense committee who have done me the honor of evaluating my doctoral work, in the French and the Hungarian doctoral I would like to express my deepest gratitude to Pr. Olivier Dutour and Dr. Hélène Coqueugniot for their proposal to pursue a doctoral research under their supervision and cosupervision, and to Dr. György Pálfi, for confidently accepting an unknown French student under his supervision, in the frame of a French-Hungarian cotutelle doctorate. At a time of doubt and questioning, I was very lucky to be offered this generous opportunity, which turned into a life-changing experience. I am very much obliged to the three of you for your continuous support, guidance, confidence, benevolence, patience, efforts, and knowledge. It has been a great honor and a privilege to collaborate with you, and it was extremely enriching, on both academic and personal level.

I also gratefully acknowledge the collaboration of Pr. László Révész (University of Szeged), who, as the leading expert on the archaeology of the Hungarian Conquest period, accepted to be associated with this doctoral research as a co-supervisor.

I would like to express my very great appreciation to Pr. Christopher Knüsel (University of Bordeaux/PACEA) and Dr. László Paja (University of Szeged) who accepted to take part in my individual thesis follow-up committee for the EPHE, hence providing me with valuable advice for the continuation of my work.

In the frame of the cotutelle agreement, my research was conducted between research units from the two involved countries. As the host institution for the Chair of Biological My thanks also go to Dr. Christèle Baillif-Ducros (INRAP) and Dr. Evan Garofalo (University of Arizona), who provided me with useful bibliographical material, as well as Patrice Courtaud (PACEA), who also allowed me the access to the Ostéothèque de Pessac, where some skeletal materials were stored in.

I am grateful to Nicolas Lenoir (CNRS) for his help with micro-CT acquisitions at PLACAMAT (UMS 3626, CNRS/University of Bordeaux), Pessac, as well as Dr. Bruno Dutailly (CNRS) and Dr. Antony Colombo (EPHE) for their kind help and insightful comments on 3D reconstructions. I would like to express my friendly thanks to Charlotte Rittemard (EPHE) and Dany Coutinho Nogueira (EPHE), with whom everything started in Bordeaux, for the quite many shared PhD-and not PhD-related adventures. Thanks to Charlotte also for her valuable assistance with the micro-CT acquisitions and 3D reconstructions.

Many thanks to all friends and colleagues from the Department of Biological Anthropology, University of Szeged, for accepting me as a member, for the full support and encouragements, for fruitful discussions, and for all the fun: Dr. Erika Molnár, Dr. Zsolt Bereczki, Dr. László Paja, as well as János Rovó, Kitty Király, Dr. Zoltán Pintér, Krisztina Mócza, Viktória Kóger, Dr. János Balázs.

Thanks also in particular to Dr. László Paja, who was involved as well in a French-Hungarian cotutelle doctorate before me, for his kind welcome, for his care, and for the great activities.

It would take another whole dissertation to be able to thank enough especially my friends from the Department of Biological Anthropology of the University of Szeged, Dr. Olga Spekker, Orsolya Anna Váradi, Luca Kis, and Balázs Tihanyi, for their invaluable support and help throughout this PhD, and especially in the last moments, for their contribution to the preparation and submission of this dissertation. Beyond that, you are the main reason why I consider Szeged as a home.

I would like also to offer my special thanks to Balázs Tihanyi, who, in addition to his constant help, support, and kindness all along the way, on both personal and professional level, largely contributed to the successful completion of this doctoral research. The close relationship between our doctoral research topics led us, indeed, to achieve a large part of the work in collaboration, from the elaboration of a study protocol to the examination of the skeletal materials. I am particularly indebted to him for accepting to share some data that were of great interest for the study of horse riding-related skeletal changes (i.e., a notable part of the data on vertebral changes, and the data on the traumatic lesions of the upper body). It was a pleasure to follow this path with you, even when the road was paved with landmines… I would like to express my profound gratitude to Ágnes Széles and Dr. Zsolt Tihanyi for their kind welcome and for making sure that my fridge was never empty. Ágnes Széles' care and delicious (farkasfinom) homemade cooking were truly heartwarming.

Finally, there is simply nothing I could have done without the endless support, advice, and patience of my mother, Corinne.

ABSTRACT

Some changes observed on human bones can be related to activities practiced during life.

Scholars have considered the reconstruction of activities from skeletal changes in past populations as "Bioarchaeology's Holy Grail". Horse riding, in particular, has interested bioarchaeologists and paleopathologists for several decades as it brought profound and lasting changes in the history of human cultural evolution. However, the existence of various confounding factors and the lack of clear contextual evidence in connection with the skeletal remains often result in limited or unreliable interpretations of skeletal changes in terms of specific activities.

Archaeological and historical sources attest that tribes of semi-nomadic populations conquered the Carpathian Basin with powerful armies of mounted archers at the turn of the 9th and 10th centuries, which led to the foundation of the Kingdom of Hungary in the year 1000/1001. Cemeteries from that period often provide cases of deposits of archery and horse riding equipment as well as horse bones associated with the individuals in the graves. Those populations are, thus, among the most pertinent to be used to perform methodological investigations on activity-related skeletal changes, and, on horse riding, in particular.

We selected a sample of 67 individuals from the 10th-century Hungarian cemetery of Sárrétudvari-Hízóföld, in order to analyze the individuals according to the presence or absence of riding deposit in their grave. A modern comparison group of 47 presumed non-rider individuals from the documented collection of Lisbon was also selected. Only adult males were included to limit the effect of sex and age on the changes. The main objectives were to identify skeletal changes reliably related to the practice of horse riding and to improve our understanding of the populations from the Hungarian Conquest period.

Various types of skeletal changes were analyzed, including some entheseal changes (at muscles attachment sites), joint changes, vertebral changes, morphological variants, and traumatic lesions. Measurements of the lower limb bones were also used to calculate indices of shape and robusticity.

Statistical analyses mostly revealed significant differences between the Hungarian groups with or without riding deposit and the comparison group from Lisbon. They concerned especially some entheseal changes at the coxal bone, femur, tibia, and calcaneus, a morphological adaptation on the femoral neck, intervertebral disc herniations at the thoracolumbar junction, or the ovalization of the acetabulum on the coxal bone. All these traits can be linked to the riding posture, and, thus, seem to be promising indicators for the practice of horse riding. On another note, comparisons between groups revealed that the Hungarian individuals without deposit in their grave were likely riding horses as well.

Among the limitations calling for caution is the restricted size of our archaeological samples, which is one of the points that should be improved in the future. In addition, some skeletal changes, such as the entheseal changes, have a multifactorial etiology, which represents a limitation for their interpretation. In that regard, we performed the exploratory analysis of the microarchitecture of an enthesis, the radial tuberosity. Using micro-CT acquisitions and 3D reconstructions of the canals of the cortical bone, we observed that some microstructural variations could allow, with further research, distinguishing entheseal changes related to activity from those related to other factors, thus contributing to more reliable reconstructions of the activities in past populations.

In the end, we emphasize that the selection of a pertinent anthropological collection, with direct evidence of the practice of an activity, and the application of strict methodological criteria, are determinant factors for the reliable identification of activity-related skeletal changes.

RÉSUMÉ COURT

Certaines modifications observées sur les os humains peuvent permettre de reconstituer les activités des populations anciennes. L'équitation représente notamment un intérêt particulier, ayant apporté des changements profonds et durables dans l'histoire de l'évolution culturelle humaine. Cependant, divers facteurs de biais et l'absence de données contextuelles claires liées aux restes osseux donnent souvent lieu à des interprétations limitées ou peu fiables des modifications osseuses en termes d'activités spécifiques.

Les sources archéologiques et historiques attestent que des tribus de populations seminomades ont conquis le bassin des Carpates à l'aide d'armées de cavaliers-archers au tournant des 9 e et 10 e siècles, conduisant ainsi à la fondation du Royaume de Hongrie en l'an 1000/1001. Les cimetières de cette période fournissent des cas de dépôts de matériel lié à l'archerie et à l'équitation ainsi que des ossements de chevaux associés aux individus dans les tombes. Ces populations sont ainsi parmi les plus pertinentes pour mener des études méthodologiques sur les modifications osseuses liées aux activités, et notamment à la pratique cavalière.

Nous avons sélectionné 67 individus issus du cimetière hongrois de Sárrétudvari-Hízóföld (10 e siècle), pour les analyser selon la présence ou l'absence de dépôt lié au cheval dans leurs tombes. Un échantillon moderne de comparaison de 47 individus présumés non-cavaliers a également été sélectionné au sein de la collection documentée de Lisbonne. Seuls les sujets adultes masculins ont été inclus afin de limiter l'influence de variations en lien avec le sexe et l'âge. Les objectifs étaient d'identifier des modifications squelettiques liées à la pratique cavalière et d'améliorer nos connaissances sur les populations de la Conquête hongroise.

Nous avons analysé diverses modifications osseuses, au niveau des enthèses (points d'attache des muscles), articulations et vertèbres, ainsi que des variations morphologiques et lésions traumatiques. Des mesures des os des membres inférieurs ont aussi servi à calculer des indices de forme et de robustesse.

Les analyses statistiques ont principalement révélé des différences significatives entre les groupes hongrois avec ou sans mobilier et le groupe de comparaison. Celles-ci concernent notamment les modifications de certaines enthèses de l'os coxal, du fémur, du tibia et du calcanéus, une adaptation morphologique sur le col du fémur, les hernies discales à la jonction thoraco-lombaire, ou encore l'ovalisation de l'acétabulum de l'os coxal. Ces traits peuvent tous être liés à la posture du cavalier et semblent donc être des indicateurs prometteurs pour la pratique cavalière. Par ailleurs, les comparaisons ont montré que les individus hongrois sans dépôt dans leur tombe montaient aussi vraisemblablement à cheval.

Parmi les limitations, appelant malgré tout à la prudence, figure la taille restreinte de nos échantillons archéologiques, qui est l'un des points qui devront être améliorés à l'avenir. En outre, certaines modifications osseuses, comme celles des enthèses, ont une étiologie multifactorielle, limitant ainsi leur interprétation. À cet égard, nous avons mené l'analyse exploratoire de la microarchitecture d'une enthèse, la tubérosité du radius. À l'aide d'acquisitions micro-CT et de reconstructions 3D des canaux de l'os cortical, nous avons observé que des variations microstructurales pourraient permettre, avec des recherches supplémentaires, de distinguer les modifications des enthèses liées aux activités de celles liées à d'autres facteurs, contribuant ainsi à de plus fiables reconstructions des activités des populations anciennes.

Au final, le choix d'une collection anthropologique pertinente, avec des preuves directes de la pratique d'une activité, ainsi que l'application de critères méthodologiques stricts, sont autant d'éléments déterminants pour l'identification fiable de modifications squelettiques liées aux activités.

LIST OF ABBREVIATIONS

The reconstruction of activities in ancient populations

The research on activity-related skeletal changes

The study of the activities and behaviors in ancient populations represents a particularly active research area in bioarchaeology, even considered by some scholars as the "Bioarchaeology's Holy Grail" [START_REF] Jurmain | Bioarchaeology's Holy Grail: The Reconstruction of Activity[END_REF]. Bone changes of different types have been considered and interpreted for decades as activity, occupational or stress markers, with the aim of providing information about the activities of the individuals. Their analysis has involved many bioanthropologists and paleopathologists, with an important step forward accomplished from the 1980's (e.g., [START_REF] Angel | Osteoarthritis and Occupation (Ancient and Modern)[END_REF][START_REF] Merbs | Patterns of Activity-induced Pathology in a Canadian Inuit Population[END_REF][START_REF] Ruff | Structural changes in the femur with the transition to agriculture on the Georgia coast[END_REF][START_REF] Dutour | Enthesopathies (lesions of muscular insertions) as indicators of the activities of Neolithic Saharan populations[END_REF][START_REF] Kennedy | Skeletal markers of occupational stress[END_REF][START_REF] Hawkey | Activity-induced musculoskeletal stress markers (MSM) and subsistence strategy changes among ancient Hudson Bay Eskimos[END_REF][START_REF] Pálfi | Activity-induced skeletal markers in historical anthropological material[END_REF][START_REF] Robb | The interpretation of skeletal muscle sites: a statistical approach[END_REF][START_REF] Jurmain | Stories from the Skeleton[END_REF][START_REF] Al-Oumaoui | Markers of activity patterns in some populations of the Iberian Peninsula[END_REF][START_REF] Mariotti | Enthesopathies -proposal of a standardized scoring method and applications[END_REF][START_REF] Rhodes | Activity-related skeletal change in medieval humeri: Cross-sectional and architectural alterations[END_REF][START_REF] Molnar | Tracing prehistoric activities: Musculoskeletal stress marker analysis of a stone-age population on the Island of Gotland in the Baltic sea[END_REF][START_REF] Mariotti | The study of entheses: proposal of a standardised scoring method for twenty-three entheses of the postcranial skeleton[END_REF][START_REF] Perréard Lopreno | Adaptation structurelle des os du membre supérieur et de la clavicule à l'activité : analyse de l'asymétrie des propriétés géométriques de sections transverses et de mesures linéaires dans une population identifiée[END_REF][START_REF] Weiss | Muscle markers revisited: Activity pattern reconstruction with controls in a central California Amerind population[END_REF][START_REF] Villotte | Enthesopathies as occupational stress markers: Evidence from the upper limb[END_REF][START_REF] Jurmain | Bioarchaeology's Holy Grail: The Reconstruction of Activity[END_REF]Niinimäki, 2012b;Alves Cardoso & Henderson, 2013;Henderson & Alves Cardoso, 2013;[START_REF] Milella | Exploring the relationship between entheseal changes and physical activity: A multivariate study[END_REF]Henderson et al., 2016).

In some cases, material archaeological remains such as artifacts or built structures are not indicative of the activities performed by individuals during their life. The analysis of the individuals' skeletal remains represents the most direct or sometimes the only way to address the question, even if many limitations must be considered for the reconstruction of activities.

The main questions addressed in this research area concern mostly locomotion, mobility, and asymmetry patterns as well as the sexual division of labor, the socio-economic organization, and, more generally, the reconstruction of the lifestyles and behaviors in past societies.

Brief biological background

Intense and regular physical activity can lead to some pathological or non-pathological bone changes of different types. The most promising research areas in the reconstruction of activities concern especially the musculoskeletal stress markers (MSMs), nowadays rather called entheseal changes (EC), as well as osteoarthritis and bone biomechanical properties, even though other types of changes are also used as activity-related markers [START_REF] Kennedy | Skeletal markers of occupational stress[END_REF][START_REF] Larsen | Bioarchaeology: Interpreting behavior from the human skeleton[END_REF][START_REF] Capasso | Atlas of Occupational Markers on Human Remains[END_REF][START_REF] Jurmain | Bioarchaeology's Holy Grail: The Reconstruction of Activity[END_REF].

The studies in the field of activity reconstruction are based on the bone's reaction to loading and its ability to adapt its shape and structure in response to it (Niinimäki, 2012a). The performance of any physical activity involves the musculoskeletal system as the body is in motion. External loads and muscle loads are transferred to the tissues. Those mechanical stimuli, or forces, generate signals to bone cells that are transduced into a biological response, including bone remodeling, the process that removes old and damaged bone and replaces it with new tissue. Bone resorption is initiated by osteoclasts, and bone formation is initiated then by osteoblasts. In normal bone, the balance between osteoblastic and osteoclastic activity is disturbed due to an increase in loading and new bone is deposited on periosteal and endosteal surfaces of cortical bone and on trabecular surfaces in cancellous bone [START_REF] Mellon | Bone and its adaptation to mechanical loading: a review[END_REF]. This results in bone mass and morphology changes that make the bone more suitable to resist to mechanical loading, according to Wolff's law (1892). Bone cross-sectional geometry allows, for instance, to study the biomechanical properties that are adapted in response to physical activity, but it mostly provides information regarding general loading patterns (Niinimäki, 2012a;[START_REF] Tichnell | Invisible Horsewomen: Horse Riding and Social Dynamics on the Steppe[END_REF].

Unlike cross-sectional geometry, the analysis of EC is more adapted if we are interested in the study of specific activities [START_REF] Tichnell | Invisible Horsewomen: Horse Riding and Social Dynamics on the Steppe[END_REF]. Entheses are the insertion sites of tendons, ligaments, and joint capsules on the bone. A distinction can be made between two types of entheses. Fibrous entheses are mainly encountered at the metaphyseal or diaphyseal areas while fibrocartilaginous entheses include the insertions at the epiphyses and processes of long bones as well as the short bones of hands and feet and several ligaments in the spine [START_REF] Benjamin | Fibrocartilage in tendons and ligaments -an adaptation to compressive load[END_REF][START_REF] Benjamin | The anatomical basis for disease localisation in seronegative spondyloarthropathy at entheses and related sites[END_REF]. EC are pathological or non-pathological modifications at the insertion sites (La [START_REF] Cava | L'enthésite ou maladie des insertions[END_REF][START_REF] Niepel | Enthesopathy[END_REF][START_REF] Lagier | Enthèses normales et enthésopathies[END_REF][START_REF] Benjamin | The skeletal attachment of tendons-tendon 'entheses[END_REF]. These alterations are visually observable on dry bone and can take the form of new bone formation (raised margins, enthesophytes, irregular or rugose surfaces) or bone destruction (porosity, cavitations, cortical defects, erosive areas) (e.g., [START_REF] Hawkey | Activity-induced musculoskeletal stress markers (MSM) and subsistence strategy changes among ancient Hudson Bay Eskimos[END_REF][START_REF] Robb | The interpretation of skeletal muscle sites: a statistical approach[END_REF][START_REF] Mariotti | Enthesopathies -proposal of a standardized scoring method and applications[END_REF][START_REF] Villotte | Enthésopathies et activités des hommes préhistoriques : recherche méthodologique et application aux fossiles européens du Paléolithique supérieur et du Mésolithique[END_REF]Henderson et al., 2016;[START_REF] Villotte | In search of consensus: Terminology for entheseal changes (EC)[END_REF]. The precise etiology of these features remains however debated as many factors, age above all, need to be considered (Henderson et al., 2017a). Theoretically, the tissues forming the enthesis remodel in order to resist muscle tension [START_REF] Tichnell | Invisible Horsewomen: Horse Riding and Social Dynamics on the Steppe[END_REF] and osteophytic and osteolytic processes develop according to the type, level, and direction of loading applied and the deposition or resorption thresholds of the bones (Niinimäki, 2012a). Muscular activity is considered to stimulate bone remodeling by an increase in blood flow at the entheses resulting in hypertrophic muscle insertion sites, while osteophytes are thought to result from muscular tear (which leads to bone avulsion and ossification exostosis) [START_REF] Hawkey | Activity-induced musculoskeletal stress markers (MSM) and subsistence strategy changes among ancient Hudson Bay Eskimos[END_REF][START_REF] Tichnell | Invisible Horsewomen: Horse Riding and Social Dynamics on the Steppe[END_REF] and osteolytic processes might be due to continual microtrauma [START_REF] Hawkey | Activity-induced musculoskeletal stress markers (MSM) and subsistence strategy changes among ancient Hudson Bay Eskimos[END_REF]. Regarding these, some scholars also suggest that they might be related to blood vascularization in the entheses or that they could be due to the absence of a layer of cortical bone in some entheseal regions and represent remains from developmental phases during adolescence (Henderson et al., 2017a). In the end, although various determinant factors need to be considered, EC are more promising for studying the effect of specific activities as each activity involves specific muscles and continual stress of a muscle can presumably result in changes observed at the level of the involved entheses [START_REF] Tichnell | Invisible Horsewomen: Horse Riding and Social Dynamics on the Steppe[END_REF].

Osteoarthritis, or degenerative joint disease, represents the third main research area in the reconstruction of activities, partly because it has been used widely and relatively early as a marker of activity [START_REF] Ortner | Description and classification of degenerative bone changes in the distal joint surfaces of the humerus[END_REF][START_REF] Jurmain | Stress and the etiology of osteoarthritis[END_REF][START_REF] Angel | Osteoarthritis and Occupation (Ancient and Modern)[END_REF][START_REF] Merbs | Patterns of Activity-induced Pathology in a Canadian Inuit Population[END_REF]. Apart from dental lesions, osteoarthritis is also the most commonly observed condition in skeletal remains [START_REF] Waldron | Palaeopathology[END_REF]. The bone changes observed at the synovial joints include marginal osteophytes and contour deformation, as well as porosity, bone formation, and eburnation on the joint surface (Buikstra & Ubelaker, 1994;[START_REF] Waldron | Palaeopathology[END_REF][START_REF] Jurmain | Bioarchaeology's Holy Grail: The Reconstruction of Activity[END_REF]. These alterations appear following the breakdown of the articular cartilage of the joint and the inflammation in the synovial membrane. Vascularization of the subchondral bone, in particular, is responsible for the formation of new bone [START_REF] Waldron | Palaeopathology[END_REF]. The discussions on the link between osteoarthritis and activities are based on the fact that it has been considered as resulting from repetitive mechanical loading and that repetitive tasks could, therefore, lead to severe osteoarthritic features on specific joints [START_REF] Weiss | Osteoarthritis revisited: A contemporary review of aetiology[END_REF]. Nowadays, it is acknowledged from clinical research that the etiology of osteoarthritis is multifactorial [START_REF] Larsen | Bioarchaeology: Interpreting behavior from the human skeleton[END_REF][START_REF] Resnick | Diagnosis of Bone and Joint Disorders (4th Edition)[END_REF]Ortner, 2003;[START_REF] Weiss | Osteoarthritis revisited: A contemporary review of aetiology[END_REF][START_REF] Waldron | Palaeopathology[END_REF][START_REF] Jurmain | Bioarchaeology's Holy Grail: The Reconstruction of Activity[END_REF].

Main limitations in the research on activity-related skeletal changes

Several authors reviewed the challenges related to the use of skeletal changes for the reconstruction of activities in past societies and suggest to use them with caution [START_REF] Dutour | Activités physiques et squelette humain : le difficile passage de l'actuel au fossile[END_REF][START_REF] Dutour | Chasse et activités physiques dans la Préhistoire : les marqueurs osseux d'activités chez l'homme fossile[END_REF][START_REF] Weiss | Osteoarthritis revisited: A contemporary review of aetiology[END_REF][START_REF] Jurmain | Bioarchaeology's Holy Grail: The Reconstruction of Activity[END_REF][START_REF] Villotte | Understanding entheseal changes: Definition and life course changes[END_REF]. A major issue with activity-related skeletal changes (ARSC) is their lack of specificity, which is closely related to their multifactorial etiology: not only physical activity but also age, sex, body weight, body size, genetic factors, ancestry, diet or pathological conditions can indeed influence the expression of entheseal changes (EC), osteoarthritis, or bone geometry (e.g., [START_REF] Dutour | Activités physiques et squelette humain : le difficile passage de l'actuel au fossile[END_REF][START_REF] Rogers | A field guide to joint disease in archaeology[END_REF][START_REF] Wilczak | Consideration of sexual dimorphism, age, and asymmetry in quantitative measurements of muscle insertion sites[END_REF]Knüsel, 2000b;[START_REF] Crubezy | Epidemiology of osteoarthritis and enthesopathies in a European population dating back 7700 years[END_REF][START_REF] Weiss | Osteoarthritis revisited: A contemporary review of aetiology[END_REF][START_REF] Niinimäki | What do muscle marker ruggedness scores actually tell us[END_REF][START_REF] Jurmain | Bioarchaeology's Holy Grail: The Reconstruction of Activity[END_REF][START_REF] Milella | The effect of age, sex, and physical activity on entheseal morphology in a contemporary Italian skeletal collection[END_REF][START_REF] Weiss | Sex differences in musculoskeletal stress markers: Problems with activity pattern reconstructions[END_REF][START_REF] Niinimäki | The relationship between intensity of physical activity and entheseal changes on the lower limb[END_REF][START_REF] Ruff | Long bone structural analyses and the reconstruction of past mobility: A historical review[END_REF][START_REF] Schrader | Activity, Diet and Social Practice. Addressing Everyday Life in Human Skeletal Remains[END_REF]. These systemic factors can expose an individual to risk for developing changes, while other factors can also have a local influence, such as musculoskeletal anomalies, joint alignment or injury, which can, for instance, expose directly a joint to risk for osteoarthritis [START_REF] Dutour | Activités physiques et squelette humain : le difficile passage de l'actuel au fossile[END_REF][START_REF] Schrader | Activity, Diet and Social Practice. Addressing Everyday Life in Human Skeletal Remains[END_REF] (Figure 1). Among all those factors, age is probably the most important one to be considered when dealing with ARSC. Older individuals are logically more likely to develop degenerative joint changes. This could be linked with "cumulative wear-and-tear (i.e., the repetitive use of a joint over one's life course), sarcopenia, decreased bone turn over, as well as a reduced capacity for soft tissue repair" in the case of osteoarthritis (Schrader, 2019: 61). Regarding EC, while the high correlation with age is now widely recognized (e.g., [START_REF] Weiss | Understanding muscle markers: Aggregation and construct validity[END_REF][START_REF] Weiss | Understanding muscle markers: Lower limbs[END_REF][START_REF] Alves Cardoso | Enthesopathy formation in the humerus: Data from known age-at-death and known occupation skeletal collections[END_REF][START_REF] Milella | The effect of age, sex, and physical activity on entheseal morphology in a contemporary Italian skeletal collection[END_REF], it is still unclear if it is the consequence of their accretion over life, an increased susceptibility to remodeling, a reduction in tendon vascularity, a decrease in cortical bone, or the loss of muscle mass (see [START_REF] Schrader | Activity, Diet and Social Practice. Addressing Everyday Life in Human Skeletal Remains[END_REF]. Sex must also be considered as females seem to be at higher risk of developing osteoarthritis. Possible reasons are a postmenopause reduction in estrogen levels, lessened bone mineral density, bone composition, ligament laxity, lower cartilage volume, pregnancy, and neuromuscular strength (see [START_REF] Schrader | Activity, Diet and Social Practice. Addressing Everyday Life in Human Skeletal Remains[END_REF]. Moreover, the differences in muscle mass between females and males could also affect entheses, with males being more susceptible to develop larger and severe EC [START_REF] Weiss | Understanding muscle markers: Aggregation and construct validity[END_REF][START_REF] Weiss | Understanding muscle markers: Lower limbs[END_REF][START_REF] Weiss | Sex differences in musculoskeletal stress markers: Problems with activity pattern reconstructions[END_REF][START_REF] Nikita | Osteoarchaeology. A guide to the macroscopic study of human skeletal remains[END_REF][START_REF] Schrader | Activity, Diet and Social Practice. Addressing Everyday Life in Human Skeletal Remains[END_REF]. Besides sex and age, it has also been suggested that there is an inter-individual variation in bone production and bone resorption which may affect the expression of ARSC, with individuals who would be "bone-formers", and others who would rather be "bone-losers" [START_REF] Rogers | Bone formers: osteophyte and enthesophyte formation are positively associated[END_REF][START_REF] Mays | Bone-formers and bone-losers in an archaeological population[END_REF][START_REF] Schrader | Activity, Diet and Social Practice. Addressing Everyday Life in Human Skeletal Remains[END_REF].

Furthermore, it is now widely acknowledged that metabolic and inflammatory disorders like diffuse idiopathic skeletal hyperostosis (DISH) or seronegative spondyloarthropathies can lead to the development of EC (e.g., [START_REF] Villotte | Understanding entheseal changes: Definition and life course changes[END_REF]. While there were early warnings of caution regarding this aspect [START_REF] Dutour | Enthesopathies (lesions of muscular insertions) as indicators of the activities of Neolithic Saharan populations[END_REF][START_REF] Dutour | Activités physiques et squelette humain : le difficile passage de l'actuel au fossile[END_REF][START_REF] Pálfi | Traces des activités sur les squelettes des anciens Hongrois[END_REF], it is only recently that studies relying on EC tend to exclude systematically the individuals affected by such diseases from samples.

A further limitation in the analysis of activity-related markers is the large variety of scoring methods, concerning osteoarthritis [START_REF] Crubézy | Interactions entre facteurs bio-culturels, pathologie et caractères discrets. Exemple d'une population mediévale : Canac (Aveyron)[END_REF]Buikstra & Ubelaker, 1994;[START_REF] Rogers | A field guide to joint disease in archaeology[END_REF] and entheseal changes [START_REF] Crubézy | Interactions entre facteurs bio-culturels, pathologie et caractères discrets. Exemple d'une population mediévale : Canac (Aveyron)[END_REF][START_REF] Hawkey | Activity-induced musculoskeletal stress markers (MSM) and subsistence strategy changes among ancient Hudson Bay Eskimos[END_REF][START_REF] Mariotti | Enthesopathies -proposal of a standardized scoring method and applications[END_REF][START_REF] Villotte | Connaissances médicales actuelles, cotation des enthésopathies : nouvelle méthode[END_REF][START_REF] Mariotti | The study of entheses: proposal of a standardised scoring method for twenty-three entheses of the postcranial skeleton[END_REF][START_REF] Villotte | Enthesopathies as occupational stress markers: Evidence from the upper limb[END_REF]Henderson et al., 2013), as well as the large scale of methods of statistical analysis used in this type of research [START_REF] Nikita | Osteoarchaeology. A guide to the macroscopic study of human skeletal remains[END_REF][START_REF] Schrader | Activity, Diet and Social Practice. Addressing Everyday Life in Human Skeletal Remains[END_REF]. This makes very difficult the comparisons between studies. Regarding EC, in particular, their relation to activity has proven not to be straightforward and the scoring methods appear not to be entirely adequate, leading some to go further and investigate the microarchitecture of the entheses. The results of the study by Djukic and collaborators (2015), who scanned several entheses using microcomputed tomography, suggest that stages of scored macroscopic EC do not reflect the microscopic organization of entheses, except maybe in the most severe cases. Furthermore, Michopoulou and colleagues (2015;2017) tested the correlation between several scoring methods and activity and observed that activity was rarely significant as a factor affecting EC expression (compared to age and body mass for instance), suggesting that the tested scoring methods do no effectively reflect activity. Regarding the analysis of bone geometrical features for research on activities, external macroscopic measurements are commonly used for quantifying robusticity but are limited compared to the potential of cross-sectional bone geometry, which is however characterized by technical, financial, and time challenges as it ideally requires the use of computed tomography, more accurate than plane radiography for example [START_REF] Stock | Which measures of diaphyseal robusticity are robust? A comparison of external methods of quantifying the strength of long bone diaphyses to cross-sectional geometric properties[END_REF][START_REF] Jurmain | Bioarchaeology's Holy Grail: The Reconstruction of Activity[END_REF][START_REF] Ruff | Long bone structural analyses and the reconstruction of past mobility: A historical review[END_REF]. In general, the sample size has also often been recognized as problematic in the field of activity reconstruction (e.g., [START_REF] Henderson | Accounting for multiple effects and the problem of small sample sizes in osteology: a case study focussing on entheseal changes[END_REF]) -being closely dependent on bone preservation -as well as, in particular, the lack of documented out-groups of sufficient size for comparison (Knüsel, 2000b).

Another issue that concerns EC, in particular, comes from the demonstration of the distinction between two types of entheses, fibrocartilaginous and fibrous ones, as mentioned earlier [START_REF] Benjamin | The anatomical basis for disease localisation in seronegative spondyloarthropathy at entheses and related sites[END_REF][START_REF] Benjamin | The skeletal attachment of tendons-tendon 'entheses[END_REF]. Several studies suggest that fibrocartilaginous entheses have a stronger correlation with activity than fibrous ones [START_REF] Villotte | Enthesopathies as occupational stress markers: Evidence from the upper limb[END_REF][START_REF] Havelková | Enthesopathies and activity patterns in the Early Medieval Great Moravian population: Evidence of division of labour[END_REF][START_REF] Villotte | Understanding entheseal changes: Definition and life course changes[END_REF][START_REF] Weiss | Examining Activity Patterns and Biological Confounding Factors: Differences between Fibrocartilaginous and Fibrous Musculoskeletal Stress Markers[END_REF], which could be explained by differences in their structure and the way tendons attach to the bone [START_REF] Benjamin | The skeletal attachment of tendons-tendon 'entheses[END_REF]. Fibrous entheses would also be less promising activity markers due to the difficulty to identify their limits and to describe their changes compared to their "normal" aspect, which is not clearly defined [START_REF] Villotte | Understanding entheseal changes: Definition and life course changes[END_REF][START_REF] Villotte | In search of consensus: Terminology for entheseal changes (EC)[END_REF][START_REF] Nikita | Osteoarchaeology. A guide to the macroscopic study of human skeletal remains[END_REF].

Furthermore, besides the multifactorial etiology of ARSC, other general analytical pitfalls must be acknowledged and avoided in the attempt to reconstruct activities in past populations from the analysis of skeletal changes. They concern the problem of transposition between present and past activities (i.e., the manner in which they are and were performed), the lack of clinical evidence for validation of the link between a specific activity and a specific marker identified from archaeological materials, or the lack of analogy regarding activities that are no longer practiced today [START_REF] Dutour | Activités physiques et squelette humain : le difficile passage de l'actuel au fossile[END_REF][START_REF] Dutour | Chasse et activités physiques dans la Préhistoire : les marqueurs osseux d'activités chez l'homme fossile[END_REF]. Besides the lack of specificity of the markers mentioned previously, which means that identical skeletal changes in different individuals can result from different activities or various other causes, the relative sensitivity of the markers should also be acknowledged. A specific activity may not systematically lead to the expression of similar skeletal changes in different individuals, or even to the expression of any skeletal changes at all [START_REF] Dutour | Chasse et activités physiques dans la Préhistoire : les marqueurs osseux d'activités chez l'homme fossile[END_REF]. In addition, a specific activity rarely results in a single type of change, therefore a single specific marker should not be enough to confirm an activity hypothesis; only the combination of several different markers, consistent with each other, may allow making a reliable association with a particular activity [START_REF] Dutour | Activités physiques et squelette humain : le difficile passage de l'actuel au fossile[END_REF][START_REF] Dutour | Chasse et activités physiques dans la Préhistoire : les marqueurs osseux d'activités chez l'homme fossile[END_REF]. The existence of relevant archaeological data that can be linked whether in a conclusive or a compatible way to an activity is determinant for the selection of any study material in order to limit the influence of the methodological biases mentioned above [START_REF] Dutour | Activités physiques et squelette humain : le difficile passage de l'actuel au fossile[END_REF][START_REF] Dutour | Chasse et activités physiques dans la Préhistoire : les marqueurs osseux d'activités chez l'homme fossile[END_REF].

Finally, we should keep in mind that bone changes do not reflect the consequences of a single activity performed during life, but that "the skeleton registers a mosaic of activities over the course of each individual's lifetime" (Kennedy, 1998: 308).

The identification of horse riding

Why is horse riding so interesting?

Among all activities, horse riding brought profound and lasting changes in the history of human cultural evolution concerning major aspects such as trade, settlement, warfare, subsistence, social organization and political ideology [START_REF] Anthony | The origins of horseback riding[END_REF][START_REF] Anthony | The Horse, the Wheel, and Language: How Bronze-Age Riders from the Eurasian Steppes Shaped the Modern World[END_REF]. The use of horses for transportation also considerably contributed to the circulation of languages, Indo-European ones in particular, as well as cultures and diseases, among other things [START_REF] Anthony | The Horse, the Wheel, and Language: How Bronze-Age Riders from the Eurasian Steppes Shaped the Modern World[END_REF][START_REF] Outram | The earliest horse harnessing and milking[END_REF][START_REF] Librado | The Evolutionary Origin and Genetic Makeup of Domestic Horses[END_REF][START_REF] De Barros Damgaard | The first horse herders and the impact of early Bronze Age steppe expansions into Asia[END_REF][START_REF] Gaunitz | Ancient genomes revisit the ancestry of domestic and Przewalski's horses[END_REF].

Archaeological evidence suggests that horse domestication likely started in the Copper Age Botai hunter-herder culture, in the northern Kazakh steppe, around 3500-3000 years BCE [START_REF] Outram | The earliest horse harnessing and milking[END_REF][START_REF] De Barros Damgaard | The first horse herders and the impact of early Bronze Age steppe expansions into Asia[END_REF][START_REF] Gaunitz | Ancient genomes revisit the ancestry of domestic and Przewalski's horses[END_REF]. There, not only horse burials were discovered but also remains of tools associated with the production of leather thong and traces of equine milk fats in ceramics. These elements, combined with bit-related pathologies on the teeth in horse remains tend to support the practice of milking and harnessing, and thus, of pastoral husbandry [START_REF] Outram | The earliest horse harnessing and milking[END_REF][START_REF] Gaunitz | Ancient genomes revisit the ancestry of domestic and Przewalski's horses[END_REF].

Horses can be involved as much for transportation than for agricultural and warfare activities. Their importance for humans can be detected in numerous artistic representations, in the material culture, in historical texts as well as in the funerary practices [START_REF] Hyland | The Medieval Warhorse from Byzantium to the Crusades[END_REF][START_REF] Garofalo | The osteologic markers of horseback riding: An examination of two medieval English populations[END_REF][START_REF] Outram | Horses for the dead: Funerary foodways in Bronze Age Kazakhstan[END_REF][START_REF] Baillif-Ducros | La pratique de la monte à cheval au haut Moyen Âge (fin Ve-VIIe siècle) dans le nord-est de la Gaule. État des connaissances archéologiques[END_REF]. As an example of their social importance, we can mention the development of relay stations for horses in different societies since Antiquity. They allowed the fast transportation of people (for private or professional purposes) and materials through territories over long distances and thereby contributed to the shaping of road networks, such as in France between the 17th and the 19th centuries [START_REF] Bretagnolle | Les routes de la poste à cheval, de 1632 à 1833[END_REF]. On another note, the Bayeux Tapestry, which depicts the events that lead to the Norman Conquest of England by William the Conqueror in 1066, offers a vivid illustration of the importance of horses in warfare. Through numerous animal representations, the tapestry reveals the significant place of horses in the Norman society and the fundamental role played by the cavalry (especially mounted lancers) during the Battle of Hastings, after the transportation of several thousands of horses across the Channel [START_REF] Bouet | Les chevaux dans la tapisserie de Bayeux[END_REF] (Figure 2).

The practice of depositing complete horses in graves seems to go back to the late Roman Iron Age (1-375 CE) while separate horse burials can be found in central and northern Europe from the early and the late Iron Age [START_REF] Jennbert | Animal graves: Dog, horse and bear[END_REF]. When an animal is deposited in a separate pit, it can be considered as an animal grave. In such cases, it is possible to state that the people responsible for this burial cared for the animal and had a purpose [START_REF] Jennbert | Animal graves: Dog, horse and bear[END_REF].

Replacing oxen, onagers, and donkeys as draught animals, horses were considered as a prestige animal [START_REF] Garofalo | The osteologic markers of horseback riding: An examination of two medieval English populations[END_REF]. During different eras, like in the Middle Ages, riding a horse was often a sign of social distinction, as owning horses required specific infrastructures, equipment, and assigned workforce for care and maintenance [START_REF] Hyland | The horse in the Middle Ages[END_REF][START_REF] Baillif-Ducros | La pratique de la monte à cheval au haut Moyen Âge (fin Ve-VIIe siècle) dans le nord-est de la Gaule. État des connaissances archéologiques[END_REF]. Horse riding was regularly performed by particular subgroups in societies and was, therefore, an activity associated with the identities of those specific groups and was bearing symbolic meaning [START_REF] Hyland | The horse in the Middle Ages[END_REF][START_REF] Tichnell | Invisible Horsewomen: Horse Riding and Social Dynamics on the Steppe[END_REF]. Furthermore, in many cultures (e.g., Scythians, Celts, Gauls, Avars, Magyars), the horse had strong spiritual importance and played a role during various funerary rituals and practices [START_REF] Garofalo | The osteologic markers of horseback riding: An examination of two medieval English populations[END_REF][START_REF] Bede | Du dépôt animalier au système de représentation d'une société. Une réflexion méthodologique sur l'interprétation des pratiques funéraires à travers l'exemple des sépultures dites « de chevaux » et « de cavaliers » de la période avare (Bassin des Carpates, fin VIe s.-milieu IXe s[END_REF].

With this in mind, it is clear that a better understanding of who exactly were horse riders during their life can shed light on different aspects of past societies. For instance, for some ancient populations of nomadic pastoralists, the sparseness of archaeological remains and the lack of internal textual evidence, among other causes, may result in a partial or oversimplified understanding regarding different aspects of the societal organization [START_REF] Tichnell | Invisible Horsewomen: Horse Riding and Social Dynamics on the Steppe[END_REF].

Considering the extreme importance of horse riding in their life, the analysis of this practice in those populations can bring elements of answers, and, while ethnographic studies can be very informative, the examination of skeletal remains for horse riding-related bone changes represents the most direct source of information [START_REF] Tichnell | Invisible Horsewomen: Horse Riding and Social Dynamics on the Steppe[END_REF].

What do we know from sports medicine and modern riders?

Although the techniques and style of riding, the equipment, and the morphology of the horses used nowadays by modern riders are not directly comparable with those used by past populations in different regions of the world, clinical sources can bring relevant complementary data [START_REF] Mcgrath | A review of the archaeological and sports medicine literature to determine the biomechanical markers of equestrian activity[END_REF]. For both modern and ancient riders, some features must, indeed, be common in relation to the posture on the horse and the muscles needed to maintain it, notably if stirrups were used.

In the position privileged by riders, the pelvis is in retroversion (tilted backward), the back is vertical and straight, and the lumbar lordosis is diminished, allowing better absorption of vertical stresses [START_REF] Auvinet | Lombalgies et équitation[END_REF][START_REF] Humbert | L'équitation et ses conséquences sur le rachis lombaire du cavalier : à propos de 123 observations[END_REF]. Sitting astride forces the femurs into abduction while pointing the toes ahead rotates them medially and gripping the horse engages the adductors. While it is recommended that the heel be aligned with the shoulder and the hip, leading to a semi-flexed knee, variations in the riding style also see the knee being semiextended, with the heel put forward [START_REF] Garofalo | The osteologic markers of horseback riding: An examination of two medieval English populations[END_REF].

The muscles that are engaged in horse riding cover a wide range of movements and include especially the adductors (hip adduction), the gluteals (hip extension, abduction, medial and lateral rotation), the quadriceps (knee extension, hip flexion), the hamstrings (knee flexion, hip extension), the hip rotators (hip lateral rotation) and the calf muscle (plantarflexion). Among them, the adductors are often presented as particularly important for riding as they keep the legs together on the horse, which is not a common action otherwise in daily life [START_REF] Baillif-Ducros | Approche méthodologique pour distinguer un ensemble lésionnel fiable de la pratique cavalière. Exemple du squelette de la tombe 11 du site de « La Tuilerie » à Saint-Dizier (Haute-Marne), VIe siècle[END_REF][START_REF] Willson | The riding muscles and their function in riding[END_REF][START_REF] Djukic | Morphological appearance of muscle attachment sites on lower limbs: Horse riders versus agricultural population[END_REF]. The abdominal muscles are also determinant for the balance and the control and stabilization of the posture. Finally, the shoulder and trunk stabilizers are important notably for accurate movements of the arms that control the reins (when used) and for the head posture [START_REF] Willson | The riding muscles and their function in riding[END_REF]. The regular and intensive use of those muscles for the highly demanding activity that is horse riding is likely to lead to muscular injuries. Furthermore, due to the speed, height, weight, and strength of the horse, riding represents -and has always represented -a potentially dangerous activity that puts the rider at risk for injuries of different types [START_REF] Bixby-Hammett | Common injuries in horseback riding. A review[END_REF][START_REF] Garofalo | The osteologic markers of horseback riding: An examination of two medieval English populations[END_REF][START_REF] Ball | Equestrian injuries: Incidence, injury patterns, and risk factors for 10 years of major traumatic injuries[END_REF]. In terms of potential of injuries, horse riding is even more dangerous than activities such as automobile racing, motorcycle riding, skiing, football, and rugby, and it is also considered to be the sport with the highest mortality [START_REF] Ball | Equestrian injuries: Incidence, injury patterns, and risk factors for 10 years of major traumatic injuries[END_REF].

Sports medicine describes the injuries affecting modern riders, whether they perform horse riding in a professional or a leisure context. Based on numerous studies published between 1959 and 1987, concerning European and American individuals, the described injuries concern mostly the upper extremity (from 24 to 61 % of the reported cases depending on the sources) followed by the lower extremity (18-36 %), while about 20 % of cases concern the head and the face and from 4 to 27 % are spinal injuries [START_REF] Bixby-Hammett | Common injuries in horseback riding. A review[END_REF]). The second most common type of injuries, after the soft tissue injuries, and before the concussions, are fractures. While the majority of the accidents occur when the horse is mounted, mostly being due to a fall, 1 to 27 % occur while handling or taking care of the horse on foot and are related to the animal itself (kicking, biting, or stepping on the rider). It was also noted that it is rather common (37 %) to suffer several times horse-related injuries during the course of a lifetime [START_REF] Bixby-Hammett | Common injuries in horseback riding. A review[END_REF].

In a different study that relied on a survey addressed to adult patients who had suffered major equestrian injuries in Alberta, Canada, between 1995 and2005, that percentage (subjects who had already suffered previous equestrian injuries) reached 47 % [START_REF] Ball | Equestrian injuries: Incidence, injury patterns, and risk factors for 10 years of major traumatic injuries[END_REF]. This study also reveals that, as for the cause of traumas, 60 % of patients were thrown off or fell off the horse while 16 % were crushed by a falling horse, 8 % were kicked, 4 % were stepped on, and the remaining 13 % cases were injured by other mechanisms. It can also be noted that 45 % of the patients required surgery, while 7 % died because of their equestrian injuries.

Furthermore, in this sample, the injuries concerned the chest (54 %), head (48 %), abdomen (22 %) and extremities (17 %), with, in particular, skull (18 %), extremity (17 %), spinal (17 %) and pelvic fractures (15 %) [START_REF] Ball | Equestrian injuries: Incidence, injury patterns, and risk factors for 10 years of major traumatic injuries[END_REF].

Other studies focusing more precisely on traumas revealed that the extremities were the most commonly affected regions (46,1-54,4 %), followed by the trunk (28,9 %) and the head and neck (16,6-23,8 %) in samples of patients from Sweden and the United States analyzed in the early 2000s [START_REF] Loder | The Demographics of Equestrian-Related Injuries in the United States: Injury Patterns, Orthopedic Specific Injuries, and Avenues for Injury Prevention[END_REF][START_REF] Altgärde | Horse-related trauma in children and adults during a two year period[END_REF][START_REF] Ki | Horse-riding accidents and injuries in historical records of Joseon Dynasty, Korea[END_REF]. Various additional sources put the frequency of the traumas in the following descending order: the upper limbs, skull, neck, lower limbs, vertebral column, thorax, and the pelvis [START_REF] Baillif-Ducros | La pratique de la monte à cheval au haut Moyen Âge (fin Ve-VIIe siècle) dans le nord-est de la Gaule. État des connaissances archéologiques[END_REF]. Traumas on the upper extremities, in particular, are essentially related to the attempt of self-protection that occurs during a fall. Moreover, pubic symphysis diastasis can also be observed, although rarely, on horse riders. A violent impact on the horse, with the pommel of the saddle, or from a fall, can, indeed, lead to a partial or complete rupture of the joint, without fracture [START_REF] Garofalo | The osteologic markers of horseback riding: An examination of two medieval English populations[END_REF][START_REF] Baillif-Ducros | La pratique de la monte à cheval au haut Moyen Âge (fin Ve-VIIe siècle) dans le nord-est de la Gaule. État des connaissances archéologiques[END_REF].

Sports medicine also describes other types of injuries, including some being the result of overuse. In polo players from Argentina, for instance, despite fractures (39 % of injuries) were also recorded sprains and strains (19 %), head concussions (19 %), muscular injuries (13 %), such as hip adductor tendinitis, and also dislocations (5 %), post-traumatic back pain (5 %) and complex lesion of the eye (2 %), as well as facial lacerations [START_REF] Costa-Paz | Injuries to polo riders: a prospective evaluation[END_REF][START_REF] Garofalo | The osteologic markers of horseback riding: An examination of two medieval English populations[END_REF].

Baillif-Ducros (2018) delivers a review of the bone lesions that can be observed on equestrian athletes. They include, on the vertebral column, lumbar hyperlordosis, spondylolysis (stress fracture on the vertebral arch) and spondylolisthesis (forward displacement of a vertebra compared to the inferior one), osteoarthritis, disc deteriorations and Schmorl's nodes (or intraosseous disc herniations), and Scheuermann's disease (kyphosis of the lower thoracic region, with wedging of the anterior portion of the vertebral bodies) (e.g., Auvinet, 1980b;[START_REF] Lang | Pathologie du rachis chez le cavalier[END_REF][START_REF] Auvinet | Lombalgies et équitation[END_REF][START_REF] Humbert | L'équitation et ses conséquences sur le rachis lombaire du cavalier : à propos de 123 observations[END_REF][START_REF] Pugh | Overuse injuries in equestrian athletes[END_REF].

The hip, a determinant region for the posture and the communication between the rider and the horse, is also affected [START_REF] Baillif-Ducros | La pratique de la monte à cheval au haut Moyen Âge (fin Ve-VIIe siècle) dans le nord-est de la Gaule. État des connaissances archéologiques[END_REF]. Microtraumatic injuries, due to muscular overuse, are recorded: adductor strain, myositis ossificans in the adductors (or rider's bone, although this lesion is not observed anymore in modern riders), and enthesopathies of the adductors (e.g., Auvinet, 1980a;[START_REF] Auvinet | Quelques aspects de la pathologie chez le cavalier, prévention 6ème journée d'étude "Quoi de neuf en matière d'etudes et de recherches sur le cheval ?[END_REF]. In the riding position, the retroversion of the pelvis can also be the cause of the femoroacetabular impingement (FAI) [START_REF] Baillif-Ducros | La pratique de la monte à cheval au haut Moyen Âge (fin Ve-VIIe siècle) dans le nord-est de la Gaule. État des connaissances archéologiques[END_REF]. In this position, the femoral head-neck junction is abnormally in contact with the acetabular rim. The repetition of this contact can lead to coxarthrosis and, presumably, to the presence of non-metric traits such as the Poirier's facet (extension of the femoral head articular surface onto the neck) and the fossa of Allen (pitted area or cortical erosion with exposition of the trabecular bone) [START_REF] Villotte | Some remarks about femoroacetabular impingement and osseous non-metric variations of the proximal femur[END_REF][START_REF] Radi | Variation of the anterior aspect of the femoral head-neck junction in a modern human identified skeletal collection[END_REF]. Furthermore, perifoveal osteophytes can also be observed, as well as pubic inguinal lesions (Baillif-Ducros, 2018).

The use of stirrups provides a point of stability for the rider. The subsequent loading for the knee joint can lead to gonarthrosis. The level of pressure and the possible lesions would notably depend on the length of the stirrups as it influences the degree of flexion of the knee (Baillif-Ducros, 2018).

However, some of those lesions have been observed only in low frequencies in riders and are not specific to horse riding. Scheuermann's disease, the FAI, or the perifoveal osteophytes, for instance, are common in other high-level athletes [START_REF] Auvinet | Lombalgies et équitation[END_REF][START_REF] Baillif-Ducros | La pratique de la monte à cheval au haut Moyen Âge (fin Ve-VIIe siècle) dans le nord-est de la Gaule. État des connaissances archéologiques[END_REF].

Despite problems of transposition between modern and ancient riders, clinical data from sports medicine are a good indicator of what skeletal changes should be investigated in particular in archaeological populations.

Archaeozoology and equestrian activity

Various studies have attempted to infer activities from the paleopathological analysis of horse skeletal remains (e.g., [START_REF] Levine | Palaeopathology and horse domestication: The case of some Iron Age horses horn the Altai Mountains, Siberia[END_REF][START_REF] Pluskowski | Potential osteoarchaeological evidence for riding and the military use of horses at Malbork Castle, Poland[END_REF][START_REF] Bulatović | Paleopathological changes in an early iron age horse skeleton from the Central Balkans (Serbia)[END_REF][START_REF] Bulatović | Paleopathological changes in an early iron age horse skeleton from the Central Balkans (Serbia)[END_REF][START_REF] Taylor | Equine cranial morphology and the archaeological identification of horseback riding: Application of 3D digital measurement to horses from Mongolia's Deer Stone-Khirigsuur Complex (1300-700 BCE)[END_REF][START_REF] Bindé | Entheseal changes: A method to detect activities in archaeological horse skeletons[END_REF]. Among several promising markers that could be identified, the presence of bit wear is even often considered as a direct and unmistakable sign of riding [START_REF] Brown | Bit Wear, Horseback Riding and the Botai Site in Kazakstan[END_REF][START_REF] Anthony | The Horse, the Wheel, and Language: How Bronze-Age Riders from the Eurasian Steppes Shaped the Modern World[END_REF][START_REF] Bendrey | New methods for the identification of evidence for bitting on horse remains from archaeological sites[END_REF][START_REF] Taylor | Equine cranial morphology and the identification of riding and chariotry in late Bronze Age Mongolia[END_REF][START_REF] Greenfield | Earliest evidence for equid bit wear in the ancient Near East: The "ass" from Early Bronze Age Tell eṣ-Ṣâfi/Gath, Israel[END_REF]. While the analysis of entheseal changes for the reconstruction of activities in human past populations is largely spread, their study on animal skeletal remains was often unconsidered. With the aim of a better understanding of their status and the activities in which they were involved in past societies, scholars recently focused their interest on the entheseal changes developed by riding, draft and pack animals, including, especially, horses [START_REF] Bendrey | An analysis of factors affecting the development of an equid cranial enthesopathy[END_REF][START_REF] Taylor | Equine cranial morphology and the identification of riding and chariotry in late Bronze Age Mongolia[END_REF][START_REF] Bertin | Les équidés du Clos d'Ugnac (Aude, France) : force de travail, ressource carnée et source de matière première, au Moyen Âge[END_REF][START_REF] Bindé | Exploring life patterns using entheseal changes in equids: Application of a new method on unworked specimens[END_REF] and reindeers (Niinimäki & Salmi, 2016;Salmi & Niinimäki, 2016). Other approaches focusing on the horses include the study of different vertebral paleopathological conditions, such as ankylosing spondylitis (or "bamboo spine") or deforming spondyloarthrosis [START_REF] Jeffcott | Disorders of the thoracolumbar spine of the horse -A survey of 443 cases[END_REF][START_REF] Lignereux | Un cheval gallo-romain inhumé dans le cimetière du site de Notre-Dame du Bon Accueil (IIe-IIIe siècle après J.-C., Rodez, Aveyron)[END_REF][START_REF] Levine | Palaeopathology and horse domestication: The case of some Iron Age horses horn the Altai Mountains, Siberia[END_REF][START_REF] Bartosiewicz | Bamboo Spine" in a Migration Period Horse from Hungary[END_REF][START_REF] Janeczek | Anatomical and Biomechanical Aspects of the Horse Spine: The Interpretation of Vertebral Fusion in a Medieval Horse from Wroclaw (Poland)[END_REF][START_REF] Lignereux | Spinal hyperostosis and ankylosis in a Gallo-Roman horse from Iwuy 'Val-de-Calvigny' (Nord, France): 'Ankylosing spondylarthritis' (spondylarthritis ankylopoetica), 'deforming spondylarthrosis' (spondylarthrosis deformans) or 'DISH' (hyperostosis vertebralis ankylopoetica)? An archeozoological and comparative nosological review[END_REF], as well as the analysis of morphological changes on the skulls, such as on the nasal bones and the premaxilla [START_REF] Taylor | Equine cranial morphology and the identification of riding and chariotry in late Bronze Age Mongolia[END_REF][START_REF] Taylor | Horseback riding, asymmetry, and changes to the equine skull: Evidence for mounted riding in Mongolia's Late Bronze Age[END_REF], even if such changes may depend on the equipment used and the riding style.

Although those bone changes are promising for the identification of riding from horse skeletal remains, the existence of a direct link between specific changes and the practice of horse riding has not yet been unarguably demonstrated with regard to human skeletal remains.

Bioanthropology and horse riding

II.D.1. Previous research on skeletal changes related to horse riding

Bioanthropological research on horse riding in ancient populations has developed in the past decades, with a growing interest from the beginning of the 1990s, especially. Among the early contributions on this topic, the work of Miller and collaborators on historic Native American Omaha and Ponca skeletal remains [START_REF] Miller | The Effect of Horseback Riding on the Omaha and Ponca: Paleopathological Indications of European Contact[END_REF][START_REF] Miller | The Effect of Horseback Riding on the Human Skeleton[END_REF][START_REF] Reinhard | Trade, contact, and female health in Northeast Nebraska[END_REF] and the paleopathological investigation performed by Pálfi and Dutour on a Hungarian cemetery of the 10th century CE [START_REF] Pálfi | Traces des activités sur les squelettes des anciens Hongrois[END_REF][START_REF] Pálfi | Activity-induced skeletal markers in historical anthropological material[END_REF][START_REF] Pálfi | Maladies dans l'Antiquité et au Moyen-Âge. Paléopathologie comparée des anciens Gallo-Romains et Hongrois[END_REF] particularly played an influential role.

A combination of skeletal changes, repeatedly observed and interpreted as signs of riding in past populations, is sometimes referred to as horse riding syndrome or horseback riding syndrome in the literature since Pálfi (1992, "syndrome du cavalier"). It covers pathological and nonpathological changes of various types, most of them having previously been reviewed [START_REF] Garofalo | The osteologic markers of horseback riding: An examination of two medieval English populations[END_REF][START_REF] Baillif-Ducros | Approche méthodologique pour distinguer un ensemble lésionnel fiable de la pratique cavalière. Exemple du squelette de la tombe 11 du site de « La Tuilerie » à Saint-Dizier (Haute-Marne), VIe siècle[END_REF][START_REF] Mcgrath | A review of the archaeological and sports medicine literature to determine the biomechanical markers of equestrian activity[END_REF][START_REF] Baillif-Ducros | La pratique de la monte à cheval au haut Moyen Âge (fin Ve-VIIe siècle) dans le nord-est de la Gaule. État des connaissances archéologiques[END_REF]. To We present here in distinct tables a summary of the main HRSC (Table 1, 2, 3, 4, and 5). Those are the skeletal changes previously observed and described by scholars on anthropological samples from archaeological context for which the practice of horse riding was presented as a possible or compatible cause. Our aim with this synthetic review is to be as exhaustive as possible. The signs that were only mentioned but not directly observed and described by the scholars are not referred to, along with the changes that were observed on the skeletons of presumed riders but not explicitly associated with the practice of horse riding. Some studies that were presented as conference communications were available to us only through their abstracts, which sometimes did not provide enough data or details to be included here (e.g., [START_REF] Jacquemard | Pratique équestre et sémiologie osseuse. Approche anthropologique à partir d'un exemple normand d'époque moderne (Notre-Dame-de-Bondeville)[END_REF][START_REF] Eng | Vertebral joint disease and trauma with horse riding among ancient Mongolian pastoralists[END_REF][START_REF] Storch | A Late-Slavic elite grave in Stolpe at river Oder, Germany[END_REF]. The studies that mention HRSC but that are not specific enough regarding their nature or their localization are briefly discussed under the relevant tables when it is relevant. Furthermore, studies focusing on HRSC but that could not obtain conclusive results (i.e., a probable association between specific changes and horse riding) are not referred to (e.g., [START_REF] Eng | Vertebral joint disease and trauma with horse riding among ancient Mongolian pastoralists[END_REF][START_REF] Sarry | La sépulture multiple laténienne du site de Gondole (Le Cendre, Puy-de-Dôme)[END_REF], on the shape of the acetabulum). Finally, when the authors describe the same horse riding-related changes on the same skeletal series in different publications, the earliest reference that was available to us is given.

Spinal changes observed References

Intervertebral disk degeneration; Facet joint osteoarthritis (including at the cervical level) Edynak, 1976 (lumbar);[START_REF] Bradtmiller | The effect of horseback riding on Arikara arthritis patterns[END_REF][START_REF] Angel | Life stresses of the free Black community as represented by the First African Baptist Church, Philadelphia, 1823-1841[END_REF][START_REF] Miller | The Effect of Horseback Riding on the Omaha and Ponca: Paleopathological Indications of European Contact[END_REF][START_REF] Pálfi | Traces des activités sur les squelettes des anciens Hongrois[END_REF][START_REF] Sandness | Vertebral Pathology in Prehistoric and Historic Skeletons from Northeastern Nebraska[END_REF][START_REF] Blondiaux | À propos de la dame d'Hochfelden et de la pratique cavalière : discussion autour des sites fonctionnels fémoraux[END_REF][START_REF] Wilczak | Consideration of sexual dimorphism, age, and asymmetry in quantitative measurements of muscle insertion sites[END_REF][START_REF] Courtaud | Osteomorphological features of nomadic riders: Some examples from Iron Age populations located in southwestern Siberia[END_REF][START_REF] Charlier | Deux cas paléopathologiques du syndrome "du cavalier" sur le site de Monte Bibele[END_REF][START_REF] Langlois | L'église de Notre-Dame-de-Bondeville et sa population (VIIe-IXe siècles, Seine-Maritime)[END_REF][START_REF] Fornaciari | The Medici Project: First anthropological and paleopathological results of the exploration of the Medici tombs in Florence[END_REF][START_REF] Wentz | Life on horseback: Palaeopathology of two Scythian skeletons from Alexandropol, Ukraine[END_REF][START_REF] Bagagli | Horseman Syndrome" in the Tuscan Early Middle Age: The Sk888 Case[END_REF][START_REF] Baillif-Ducros | Approche méthodologique pour distinguer un ensemble lésionnel fiable de la pratique cavalière. Exemple du squelette de la tombe 11 du site de « La Tuilerie » à Saint-Dizier (Haute-Marne), VIe siècle[END_REF][START_REF] Anđelinović | Skeleton changes induced by horse riding on medieval skeletal remains from Croatia[END_REF][START_REF] Eng | A bioarchaeological study of osteoarthritis among populations of northern China and Mongolia during the Bronze Age to Iron Age transition to nomadic pastoralism[END_REF][START_REF] Khudaverdyan | Multiple trauma in a horse rider from the Late Iron Age cemetery at Shirakavan, Armenia[END_REF][START_REF] Sarry | La sépulture multiple laténienne du site de Gondole (Le Cendre, Puy-de-Dôme)[END_REF][START_REF] Panzarino | Chi era e come viveva: profilo bioantropologico dell'uomo sepolto nella tomba 6[END_REF] (apophyses, asymmetrical, post-traumatic after a fall); [START_REF] Karstens | A palaeopathological analysis of skeletal remains from Bronze Age Mongolia[END_REF]Schmorl's nodes/herniations Miller & Reinhard, 1991;[START_REF] Sandness | Vertebral Pathology in Prehistoric and Historic Skeletons from Northeastern Nebraska[END_REF][START_REF] Wilczak | Consideration of sexual dimorphism, age, and asymmetry in quantitative measurements of muscle insertion sites[END_REF][START_REF] Reinhard | Identifying Equestrian Skeletal Markers[END_REF][START_REF] Langlois | L'église de Notre-Dame-de-Bondeville et sa population (VIIe-IXe siècles, Seine-Maritime)[END_REF][START_REF] Wentz | Life on horseback: Palaeopathology of two Scythian skeletons from Alexandropol, Ukraine[END_REF][START_REF] Üstündağ | A possible case of Scheuermann's disease from Akarçay Höyük, Birecik (Şanlıurfa, Turkey)[END_REF][START_REF] Bagagli | Horseman Syndrome" in the Tuscan Early Middle Age: The Sk888 Case[END_REF][START_REF] Fornaciari | A great enigma of the Italian Renaissance: paleopathological study on the death of Giovanni dalle Bande Nere (1498-1526) and historical relevance of a leg amputation[END_REF][START_REF] Anđelinović | Skeleton changes induced by horse riding on medieval skeletal remains from Croatia[END_REF][START_REF] Serna | Osteobiografía de dos individuos inhumados durante la Campaña del Desierto: el caso del sitio Chimpay (Argentina)[END_REF][START_REF] Antikas | New Finds from the Cremains in Tomb II at Aegae Point to Philip II and a Scythian Princess[END_REF][START_REF] Sarry | La sépulture multiple laténienne du site de Gondole (Le Cendre, Puy-de-Dôme)[END_REF][START_REF] Karstens | A palaeopathological analysis of skeletal remains from Bronze Age Mongolia[END_REF] Accentuated thoracic kyphosis and lumbar lordosis/Scheuermann's disease; Compression fractures [START_REF] Blondiaux | À propos de la dame d'Hochfelden et de la pratique cavalière : discussion autour des sites fonctionnels fémoraux[END_REF][START_REF] Üstündağ | A possible case of Scheuermann's disease from Akarçay Höyük, Birecik (Şanlıurfa, Turkey)[END_REF][START_REF] Baillif-Ducros | Approche méthodologique pour distinguer un ensemble lésionnel fiable de la pratique cavalière. Exemple du squelette de la tombe 11 du site de « La Tuilerie » à Saint-Dizier (Haute-Marne), VIe siècle[END_REF][START_REF] Fornaciari | A great enigma of the Italian Renaissance: paleopathological study on the death of Giovanni dalle Bande Nere (1498-1526) and historical relevance of a leg amputation[END_REF][START_REF] Sarry | La sépulture multiple laténienne du site de Gondole (Le Cendre, Puy-de-Dôme)[END_REF]Spondylolysis Miller & Reinhard, 1991;[START_REF] Pálfi | Traces des activités sur les squelettes des anciens Hongrois[END_REF][START_REF] Dutour | Palaeopathological Study of Napoleonic Mass Graves Discovered in Russia[END_REF][START_REF] Fornaciari | A great enigma of the Italian Renaissance: paleopathological study on the death of Giovanni dalle Bande Nere (1498-1526) and historical relevance of a leg amputation[END_REF]Vertebral fusion Miller & Reinhard, 1991;[START_REF] Wentz | Life on horseback: Palaeopathology of two Scythian skeletons from Alexandropol, Ukraine[END_REF] Kissing spine (or Baastrup's disease) [START_REF] Miller | The Effect of Horseback Riding on the Omaha and Ponca: Paleopathological Indications of European Contact[END_REF] Sandness and Reinhard (1992) also describe a higher frequency of spondylolysis in historic

Omaha and Ponca series compared to prehistoric ones. They associate this observation with the activities that predisposed the individuals "either to greater habitual stress, or incidences of trauma" (p. 306), without, however, explicitly mentioning horse riding, unlike they do as a possible explanation for the higher frequency of Schmorl's nodes.

Hip

Coxofemoral joint [START_REF] Bradtmiller | The effect of horseback riding on Arikara arthritis patterns[END_REF][START_REF] Miller | The Effect of Horseback Riding on the Omaha and Ponca: Paleopathological Indications of European Contact[END_REF][START_REF] Pálfi | Traces des activités sur les squelettes des anciens Hongrois[END_REF][START_REF] Courtaud | Osteomorphological features of nomadic riders: Some examples from Iron Age populations located in southwestern Siberia[END_REF][START_REF] Garofalo | The osteologic markers of horseback riding: An examination of two medieval English populations[END_REF][START_REF] Charlier | Deux cas paléopathologiques du syndrome "du cavalier" sur le site de Monte Bibele[END_REF][START_REF] Fornaciari | The Medici Project: First anthropological and paleopathological results of the exploration of the Medici tombs in Florence[END_REF]Robin, 2011 (asymmetrical); [START_REF] Fornaciari | A great enigma of the Italian Renaissance: paleopathological study on the death of Giovanni dalle Bande Nere (1498-1526) and historical relevance of a leg amputation[END_REF][START_REF] Sarry | La sépulture multiple laténienne du site de Gondole (Le Cendre, Puy-de-Dôme)[END_REF][START_REF] Baillif-Ducros | La pratique de la monte à cheval au haut Moyen Âge (fin Ve-VIIe siècle) dans le nord-est de la Gaule. État des connaissances archéologiques[END_REF] Perifoveal osteophytes on the femoral head (mentioned apart from other hip joint changes) [START_REF] Blondiaux | À propos de la dame d'Hochfelden et de la pratique cavalière : discussion autour des sites fonctionnels fémoraux[END_REF][START_REF] Fornaciari | Paleopatologia del cimitero signorile del castello di Monte di Croce (Ia fase, XI secolo)[END_REF][START_REF] Garofalo | The osteologic markers of horseback riding: An examination of two medieval English populations[END_REF][START_REF] Fornaciari | The Medici Project: First anthropological and paleopathological results of the exploration of the Medici tombs in Florence[END_REF][START_REF] Baillif-Ducros | Approche méthodologique pour distinguer un ensemble lésionnel fiable de la pratique cavalière. Exemple du squelette de la tombe 11 du site de « La Tuilerie » à Saint-Dizier (Haute-Marne), VIe siècle[END_REF][START_REF] Sarry | La sépulture multiple laténienne du site de Gondole (Le Cendre, Puy-de-Dôme)[END_REF][START_REF] Panzarino | Chi era e come viveva: profilo bioantropologico dell'uomo sepolto nella tomba 6[END_REF] [START_REF] Miller | The Effect of Horseback Riding on the Human Skeleton[END_REF] It should be clarified that the authors who mention extraspinal joint changes of the upper part of the body explain it, in most cases, as being the consequence of rein or bridle tension [START_REF] Eng | A bioarchaeological study of osteoarthritis among populations of northern China and Mongolia during the Bronze Age to Iron Age transition to nomadic pastoralism[END_REF][START_REF] Karstens | A palaeopathological analysis of skeletal remains from Bronze Age Mongolia[END_REF].

Considering the relatively early date of the following study, we should also mention that [START_REF] Edynak | Life-styles from skeletal material: a Medieval Yugoslav example[END_REF], referred to by [START_REF] Larsen | Bioarchaeological Interpretations of Subsistence Economy and Behavior from Human Skeletal Remains[END_REF] and [START_REF] Gibbon | Anthropological Archaeology[END_REF], examined a series of skeletons from Yugoslavian mounds dated from Iron Age to the medieval period, and "found that articular joints of the males' pelvic regions were more severely affected by osteoarthritis than any other joints" (Larsen, 1987: 391). The author associated this observation with the absorption of shock that occurs in horse riding, as the population included presumed riders. However, there is no precision regarding which joint, in particular, is concerned (i.e., sacroiliac or coxofemoral joint). According to [START_REF] Gibbon | Anthropological Archaeology[END_REF], Edynak observed that "males exhibited a pattern of more direct stress on all joints, and pelvic-lumbar degenerative arthritis related to the absorption of shock from below" (p. 206).

Finally, [START_REF] Panzarino | Chi era e come viveva: profilo bioantropologico dell'uomo sepolto nella tomba 6[END_REF], studying the remains of a Southern Italian (Apulia) individual from the 15th century, attribute the presence of osteochondritis dissecans at the acetabulum, femoral head, and talus to the stress related to galloping. Adductor magnus (o.) [START_REF] Miller | The Effect of Horseback Riding on the Human Skeleton[END_REF][START_REF] Pálfi | Traces des activités sur les squelettes des anciens Hongrois[END_REF]Ciurletti, 2017 Femur Greater trochanter Gluteus medius (i.); Gluteus minimus (i.) [START_REF] Miller | The Effect of Horseback Riding on the Omaha and Ponca: Paleopathological Indications of European Contact[END_REF][START_REF] Pálfi | Traces des activités sur les squelettes des anciens Hongrois[END_REF][START_REF] Molleson | A cart driver from Ur[END_REF][START_REF] Blondiaux | À propos de la dame d'Hochfelden et de la pratique cavalière : discussion autour des sites fonctionnels fémoraux[END_REF][START_REF] Molleson | Riders' Bones from Kish, Iraq[END_REF]Knüsel, 2000a (medius); [START_REF] Fornaciari | Paleopatologia del cimitero signorile del castello di Monte di Croce (Ia fase, XI secolo)[END_REF]Garofalo, 2004 (medius); [START_REF] Üstündağ | A possible case of Scheuermann's disease from Akarçay Höyük, Birecik (Şanlıurfa, Turkey)[END_REF][START_REF] Anđelinović | Skeleton changes induced by horse riding on medieval skeletal remains from Croatia[END_REF][START_REF] Antikas | New Finds from the Cremains in Tomb II at Aegae Point to Philip II and a Scythian Princess[END_REF][START_REF] Khudaverdyan | Multiple trauma in a horse rider from the Late Iron Age cemetery at Shirakavan, Armenia[END_REF][START_REF] Ciurletti | Analisi biomeccanica del femore e del coxale per comprendere l'economia di sussistenza e il comportamento occupazionale legato all'uso del cavallo nella populazione della necropoli di Olmo di Nogara (Bronzo medio, Verona)[END_REF]Panzarino & Sublimi Saponetti, 2017 Trochanteric fossa Obturator externus (i.); Obturator internus (i.) [START_REF] Blondiaux | Essai d'anthropologie physique et de paléopathologie des populations du nord de la Gaule au haut Moyen Age[END_REF][START_REF] Molleson | A cart driver from Ur[END_REF][START_REF] Blondiaux | À propos de la dame d'Hochfelden et de la pratique cavalière : discussion autour des sites fonctionnels fémoraux[END_REF][START_REF] Molleson | Riders' Bones from Kish, Iraq[END_REF]Belcastro et al., 2001;[START_REF] Fornaciari | The Medici Project: First anthropological and paleopathological results of the exploration of the Medici tombs in Florence[END_REF][START_REF] Bartsiokas | The lameness of King Philip II and Royal Tomb I at Vergina, Macedonia[END_REF][START_REF] Khudaverdyan | Multiple trauma in a horse rider from the Late Iron Age cemetery at Shirakavan, Armenia[END_REF]Ciurletti, 2017 Lesser trochanter Iliopsoas (i.): iliacus, psoas major, psoas minor [START_REF] Pálfi | Traces des activités sur les squelettes des anciens Hongrois[END_REF][START_REF] Molleson | A cart driver from Ur[END_REF]Belcastro et al., 2001;[START_REF] Charlier | Deux cas paléopathologiques du syndrome "du cavalier" sur le site de Monte Bibele[END_REF][START_REF] Fornaciari | A great enigma of the Italian Renaissance: paleopathological study on the death of Giovanni dalle Bande Nere (1498-1526) and historical relevance of a leg amputation[END_REF][START_REF] Panzarino | Chi era e come viveva: profilo bioantropologico dell'uomo sepolto nella tomba 6[END_REF][START_REF] Djukic | Morphological appearance of muscle attachment sites on lower limbs: Horse riders versus agricultural population[END_REF]

Gluteal tuberosity

Gluteus maximus (i.) [START_REF] Pálfi | Traces des activités sur les squelettes des anciens Hongrois[END_REF][START_REF] Blondiaux | À propos de la dame d'Hochfelden et de la pratique cavalière : discussion autour des sites fonctionnels fémoraux[END_REF][START_REF] Molleson | Riders' Bones from Kish, Iraq[END_REF]Belcastro et al., 2001;[START_REF] Fornaciari | Paleopatologia del cimitero signorile del castello di Monte di Croce (Ia fase, XI secolo)[END_REF][START_REF] Charlier | Deux cas paléopathologiques du syndrome "du cavalier" sur le site de Monte Bibele[END_REF][START_REF] Uerpmann | Post-Neolithic Human Remains from the Jebel al-Buhais Area[END_REF][START_REF] Tichnell | Invisible Horsewomen: Horse Riding and Social Dynamics on the Steppe[END_REF][START_REF] Pulcini | La necropoli di Olmo di Nogara (Verona). Studio paleobiologico dei resti umani per la ricostruzione dell[END_REF][START_REF] Bartsiokas | The lameness of King Philip II and Royal Tomb I at Vergina, Macedonia[END_REF]Ciurletti, 2017 Pectineal line Pectineus (i.) [START_REF] Pálfi | Traces des activités sur les squelettes des anciens Hongrois[END_REF][START_REF] Charlier | Deux cas paléopathologiques du syndrome "du cavalier" sur le site de Monte Bibele[END_REF][START_REF] Fornaciari | The Medici Project: First anthropological and paleopathological results of the exploration of the Medici tombs in Florence[END_REF] [START_REF] Blondiaux | Essai d'anthropologie physique et de paléopathologie des populations du nord de la Gaule au haut Moyen Age[END_REF][START_REF] Miller | The Effect of Horseback Riding on the Omaha and Ponca: Paleopathological Indications of European Contact[END_REF][START_REF] Pálfi | Traces des activités sur les squelettes des anciens Hongrois[END_REF][START_REF] Molleson | A cart driver from Ur[END_REF][START_REF] Blondiaux | À propos de la dame d'Hochfelden et de la pratique cavalière : discussion autour des sites fonctionnels fémoraux[END_REF][START_REF] Molleson | Riders' Bones from Kish, Iraq[END_REF][START_REF] Courtaud | Osteomorphological features of nomadic riders: Some examples from Iron Age populations located in southwestern Siberia[END_REF]Belcastro et al., 2001;[START_REF] Fornaciari | Paleopatologia del cimitero signorile del castello di Monte di Croce (Ia fase, XI secolo)[END_REF][START_REF] Garofalo | The osteologic markers of horseback riding: An examination of two medieval English populations[END_REF][START_REF] Charlier | Deux cas paléopathologiques du syndrome "du cavalier" sur le site de Monte Bibele[END_REF][START_REF] Uerpmann | Post-Neolithic Human Remains from the Jebel al-Buhais Area[END_REF][START_REF] Üstündağ | A possible case of Scheuermann's disease from Akarçay Höyük, Birecik (Şanlıurfa, Turkey)[END_REF][START_REF] Anđelinović | Skeleton changes induced by horse riding on medieval skeletal remains from Croatia[END_REF][START_REF] Khudaverdyan | Multiple trauma in a horse rider from the Late Iron Age cemetery at Shirakavan, Armenia[END_REF][START_REF] Panzarino | Chi era e come viveva: profilo bioantropologico dell'uomo sepolto nella tomba 6[END_REF][START_REF] Djukic | Morphological appearance of muscle attachment sites on lower limbs: Horse riders versus agricultural population[END_REF] Lateral lip of linea aspera Vastus lateralis (o.); Biceps femoris (o., short head) [START_REF] Miller | The Effect of Horseback Riding on the Omaha and Ponca: Paleopathological Indications of European Contact[END_REF][START_REF] Pálfi | Traces des activités sur les squelettes des anciens Hongrois[END_REF][START_REF] Fornaciari | Paleopatologia del cimitero signorile del castello di Monte di Croce (Ia fase, XI secolo)[END_REF][START_REF] Üstündağ | A possible case of Scheuermann's disease from Akarçay Höyük, Birecik (Şanlıurfa, Turkey)[END_REF]Linea aspera Unspecified Pap, 1985;[START_REF] Józsa | Enthesopathies (insertion tendopathies) as indicators of overuse of tendons and muscles in ancient Hungarian populations[END_REF][START_REF] Simalcsik | Anthropological Analysis of the Human Osteological Remains Discovered in the Tumular Cemetery from Cernavodă -A2 Highway (Tumuli nos. 7, 7A, 7B)[END_REF][START_REF] Pulcini | La necropoli di Olmo di Nogara (Verona). Studio paleobiologico dei resti umani per la ricostruzione dell[END_REF][START_REF] Anđelinović | Skeleton changes induced by horse riding on medieval skeletal remains from Croatia[END_REF] Adductor magnus (i.) [START_REF] Angel | Life stresses of the free Black community as represented by the First African Baptist Church, Philadelphia, 1823-1841[END_REF][START_REF] Snow | Human Osteological Remains from the Battle of the Little Bighorn[END_REF][START_REF] Pálfi | Traces des activités sur les squelettes des anciens Hongrois[END_REF][START_REF] Molleson | Riders' Bones from Kish, Iraq[END_REF][START_REF] Charlier | Deux cas paléopathologiques du syndrome "du cavalier" sur le site de Monte Bibele[END_REF][START_REF] Tichnell | Invisible Horsewomen: Horse Riding and Social Dynamics on the Steppe[END_REF] (depending on the riding style); [START_REF] Bartsiokas | The lameness of King Philip II and Royal Tomb I at Vergina, Macedonia[END_REF][START_REF] Djukic | Morphological appearance of muscle attachment sites on lower limbs: Horse riders versus agricultural population[END_REF] Medial and lateral popliteal surface Gastrocnemius (o., medial and lateral heads) [START_REF] Miller | The Effect of Horseback Riding on the Human Skeleton[END_REF][START_REF] Pálfi | Traces des activités sur les squelettes des anciens Hongrois[END_REF][START_REF] Anđelinović | Skeleton changes induced by horse riding on medieval skeletal remains from Croatia[END_REF] Medial popliteal surface (only) Gastrocnemius (o., medial head) [START_REF] Molleson | Riders' Bones from Kish, Iraq[END_REF][START_REF] Üstündağ | A possible case of Scheuermann's disease from Akarçay Höyük, Birecik (Şanlıurfa, Turkey)[END_REF] Patella Anterior surface Quadriceps femoris (i.): vastus medialis, vastus intermedius, vastus lateralis, rectus femoris [START_REF] Pap | A Dabas (Gyón)-paphegyi XI. századi embertani széria (The anthropological series of Dabas (Gyón)-paphegy from the 11th century)[END_REF][START_REF] Józsa | Enthesopathies (insertion tendopathies) as indicators of overuse of tendons and muscles in ancient Hungarian populations[END_REF][START_REF] Charlier | Deux cas paléopathologiques du syndrome "du cavalier" sur le site de Monte Bibele[END_REF]

Tibia

Tibial tuberosity

Quadriceps femoris (i., via the patella ligament): vastus medialis, vastus intermedius, vastus lateralis, rectus femoris [START_REF] Józsa | Enthesopathies (insertion tendopathies) as indicators of overuse of tendons and muscles in ancient Hungarian populations[END_REF][START_REF] Bartsiokas | The lameness of King Philip II and Royal Tomb I at Vergina, Macedonia[END_REF] Soleal line Soleus (o.) Belcastro et al., 2001;[START_REF] Fornaciari | Paleopatologia del cimitero signorile del castello di Monte di Croce (Ia fase, XI secolo)[END_REF][START_REF] Antikas | New Finds from the Cremains in Tomb II at Aegae Point to Philip II and a Scythian Princess[END_REF][START_REF] Panzarino | Chi era e come viveva: profilo bioantropologico dell'uomo sepolto nella tomba 6[END_REF] Calcaneus

Calcaneal tuberosity

Triceps surae (i., via the Achilles tendon): soleus, gastrocnemius; Plantaris (i., via the Achilles tendon) Belcastro et al., 2001;[START_REF] Charlier | Deux cas paléopathologiques du syndrome "du cavalier" sur le site de Monte Bibele[END_REF]Bartsiokas et al., 2015 (unilateral); Khudaverdyan et al., 2016 (unilateral) In his early contribution, [START_REF] Angel | Osteoarthritis and Occupation (Ancient and Modern)[END_REF] describes "adductor exostoses ('rider's bone')" on the skeletons of two modern cowboys, without, unfortunately, explaining their precise localization (e.g., linea aspera or adductor tubercle).

It should also be noted that [START_REF] Uerpmann | Post-Neolithic Human Remains from the Jebel al-Buhais Area[END_REF] describe skeletal changes that are usually attributed to horse riding and associate them to the possible practice of riding camels. This is supported by the context of Post-Neolithic Arabia and, especially, by the discovery of a camel skeleton in a grave, probably associated with a human burial. on the femur as being induced by horse riding, without more precision. It might refer to enthesophytes on the quadrate tubercle that is located on the intertrochanteric crest and is the insertion site of the quadratus femoris, which is not commonly related to horse riding in the anthropological or sports medicine literature.

Antikas and Wynn-Antikas (2016) note on the remains of an adult male from a royal Macedonian tomb that "enthesophytes and riding markers exist on the iliac crest, the neck, major trochanter and linea aspera of the femori as well as on the popliteal line of the tibiae" (p. 686). It is unclear what the markers or enthesophytes on the iliac crest and the neck refer to.

An observation made by [START_REF] Panzarino | Chi era e come viveva: profilo bioantropologico dell'uomo sepolto nella tomba 6[END_REF] is atypical. They consider that some entheseal changes on the hand phalanges could be related to guiding the horse by holding the reins, and that a superficial inflammation on a proximal phalanx could be due to the way of holding the bridles between the fingers.

Finally, [START_REF] Fuka | Activity markers and horse riding in Mongolia: Entheseal changes among Bronze and Iron Age human skeletal remains[END_REF] analyses the association of entheseal changes on the skeletal remains of Mongolian individuals, dated from the Bronze Age, the Iron Age, and the Xiongnu period.

The entheses are analyzed by muscle groups (shoulder, elbow, wrist, hip, and knee). Even though the detail regarding which muscles are taken into account, it is not specified which enthesis related to each muscle in particular (that is to say which origin or insertion site of which bone) is included in each composite muscle group and is affected by changes. In the end, entheseal changes related to muscle groups from the shoulder, elbow, and hip, seem to be positively associated with horse riding, with patterns of asymmetry related to the riding style:

"the positive associations of the muscle groups of the left shoulder, left elbow, and both hips suggest an activity pattern that is indicative of left-handed riding, the style of riding observed among present-day Mongolian riders" (p. 66).

Bone

Morphological variants observed References

Os coxal

Ovalization, vertical elongation of the acetabulum, expanded anterior-superior rim [START_REF] Miller | The Effect of Horseback Riding on the Omaha and Ponca: Paleopathological Indications of European Contact[END_REF][START_REF] Pálfi | Traces des activités sur les squelettes des anciens Hongrois[END_REF][START_REF] Courtaud | Osteomorphological features of nomadic riders: Some examples from Iron Age populations located in southwestern Siberia[END_REF][START_REF] Erickson | Fourier analysis of acetabular shape in Native American Arikara populations before and after acquisition of horses[END_REF][START_REF] Garofalo | The osteologic markers of horseback riding: An examination of two medieval English populations[END_REF][START_REF] Uerpmann | Post-Neolithic Human Remains from the Jebel al-Buhais Area[END_REF][START_REF] Fornaciari | The Medici Project: First anthropological and paleopathological results of the exploration of the Medici tombs in Florence[END_REF][START_REF] Üstündağ | A possible case of Scheuermann's disease from Akarçay Höyük, Birecik (Şanlıurfa, Turkey)[END_REF][START_REF] Baillif-Ducros | Approche méthodologique pour distinguer un ensemble lésionnel fiable de la pratique cavalière. Exemple du squelette de la tombe 11 du site de « La Tuilerie » à Saint-Dizier (Haute-Marne), VIe siècle[END_REF][START_REF] Baillif-Ducros | Stirrups and archaeological populations: Bioanthropological considerations for determining their use based on the skeletons of two Steppe riders[END_REF][START_REF] Fornaciari | A great enigma of the Italian Renaissance: paleopathological study on the death of Giovanni dalle Bande Nere (1498-1526) and historical relevance of a leg amputation[END_REF][START_REF] Ciurletti | Analisi biomeccanica del femore e del coxale per comprendere l'economia di sussistenza e il comportamento occupazionale legato all'uso del cavallo nella populazione della necropoli di Olmo di Nogara (Bronzo medio, Verona)[END_REF][START_REF] Baillif-Ducros | La pratique de la monte à cheval au haut Moyen Âge (fin Ve-VIIe siècle) dans le nord-est de la Gaule. État des connaissances archéologiques[END_REF] Rounded notch in the acetabulum (caused by hitting of the femoral head) [START_REF] Anđelinović | Skeleton changes induced by horse riding on medieval skeletal remains from Croatia[END_REF] Longitudinal cuts between the sacrum and iliac bone

Anđelinović et al., 2015

Femur

Variations of the anterior aspect of the femoral head-neck junction: Poirier's facet, expansion of the femoral head onto the neck, iliac imprint, Reiterfacette; Plaque, iliac imprint; Allen's fossa, anterior cervical imprint, cervical fossa [START_REF] Miller | The Effect of Horseback Riding on the Omaha and Ponca: Paleopathological Indications of European Contact[END_REF][START_REF] Blänkle | Skelette erzählen. Abhandlungen des Offenbacher Vereins für Naturkunde, Band 8. Begleitheft zur gleichnamigen Ausstellung im Stadtmuseum[END_REF][START_REF] Pálfi | Traces des activités sur les squelettes des anciens Hongrois[END_REF][START_REF] Molleson | A cart driver from Ur[END_REF][START_REF] Molleson | Riders' Bones from Kish, Iraq[END_REF][START_REF] Wilczak | Consideration of sexual dimorphism, age, and asymmetry in quantitative measurements of muscle insertion sites[END_REF]Belcastro et al., 2001;[START_REF] Garofalo | The osteologic markers of horseback riding: An examination of two medieval English populations[END_REF][START_REF] Langlois | L'église de Notre-Dame-de-Bondeville et sa population (VIIe-IXe siècles, Seine-Maritime)[END_REF][START_REF] Lösch | Paläopathologisch-anthropologische und molekulare Untersuchungen an mittelalterlichen und frühneuzeitlichen Bevölkerungsgruppen: Ernährung und Gesundheitszustand süd-und nordbayerischer Bevölkerungsstichproben[END_REF][START_REF] Üstündağ | A possible case of Scheuermann's disease from Akarçay Höyük, Birecik (Şanlıurfa, Turkey)[END_REF][START_REF] Dutour | Palaeopathological Study of Napoleonic Mass Graves Discovered in Russia[END_REF][START_REF] Fornaciari | A great enigma of the Italian Renaissance: paleopathological study on the death of Giovanni dalle Bande Nere (1498-1526) and historical relevance of a leg amputation[END_REF][START_REF] Novotny | Anthropologische Analyse der menschlichen Skelette aus Gobelsburg, Niederösterreich[END_REF][START_REF] Pulcini | La necropoli di Olmo di Nogara (Verona). Studio paleobiologico dei resti umani per la ricostruzione dell[END_REF][START_REF] Anđelinović | Skeleton changes induced by horse riding on medieval skeletal remains from Croatia[END_REF][START_REF] Bartsiokas | The lameness of King Philip II and Royal Tomb I at Vergina, Macedonia[END_REF][START_REF] Khudaverdyan | Multiple trauma in a horse rider from the Late Iron Age cemetery at Shirakavan, Armenia[END_REF][START_REF] Sarry | La sépulture multiple laténienne du site de Gondole (Le Cendre, Puy-de-Dôme)[END_REF][START_REF] Ciurletti | Analisi biomeccanica del femore e del coxale per comprendere l'economia di sussistenza e il comportamento occupazionale legato all'uso del cavallo nella populazione della necropoli di Olmo di Nogara (Bronzo medio, Verona)[END_REF] [START_REF] Miller | The Effect of Horseback Riding on the Human Skeleton[END_REF] It should be noted that the variations of the anterior aspect of the femoral head-neck junction include several changes that are named differently in the literature, or that are not even differentiated by some scholars, hence our choice to group them in Table 4 [START_REF] Villotte | Some remarks about femoroacetabular impingement and osseous non-metric variations of the proximal femur[END_REF][START_REF] Radi | Variation of the anterior aspect of the femoral head-neck junction in a modern human identified skeletal collection[END_REF]. Belcastro et al. (2001) are the only ones to distinguish the presence of Allen's fossa (in addition to the "anterior iliac imprint") and to suggest that it could be related to horse riding. [START_REF] Anđelinović | Skeleton changes induced by horse riding on medieval skeletal remains from Croatia[END_REF] mention it too, but it is unclear whether it was actually observed in their skeletal series. [START_REF] Simalcsik | Anthropological Analysis of the Human Osteological Remains Discovered in the Tumular Cemetery from Cernavodă -A2 Highway (Tumuli nos. 7, 7A, 7B)[END_REF] observe in several skeletons from early Bronze Age Romanian tumuli the presence of what they consider as markers of equestrian activities on the femurs: "the subtrochanterian relief (…) represented by the crest, fossa and additional femoral trochanter" (p. 10). Although it would be reasonable to think that this last trait refers to the third trochanter, a morphological variant that can be observed on the gluteal tuberosity, it is not commonly associated with horse riding, unlike they claim it. Moreover, it is also unclear what represents the "subtrochanterian fossa": the hypotrochanteric fossa, another variation that was never associated with horse riding either, or the trochanteric fossa, in which the presence of spicules was actually often associated with riding? The "crest" seems to refer to the linea aspera. Considering the lack of clarity, we only added this reference concerning the enthesophytes of the linea aspera (Table 3), which are explicitly mentioned later, but not the other features. [START_REF] Ciurletti | Analisi biomeccanica del femore e del coxale per comprendere l'economia di sussistenza e il comportamento occupazionale legato all'uso del cavallo nella populazione della necropoli di Olmo di Nogara (Bronzo medio, Verona)[END_REF] attributes, based on a study by [START_REF] Anđelinović | Skeleton changes induced by horse riding on medieval skeletal remains from Croatia[END_REF], the presence of female traits on the pelvis to the practice of horse riding, i.e., a wide sciatic notch and marked subpubic concavity. She observes a higher frequency of these traits in male coxal bones than in females' ones, which confirms, according to her, the stress related to horse riding. These skeletal changes seem very questionable, especially as the association between female features on the pelvis and horse riding by [START_REF] Anđelinović | Skeleton changes induced by horse riding on medieval skeletal remains from Croatia[END_REF] is only explicitly stated in the abstract of the paper, and those precise characteristics are considered as "induced by frequent riding" without any explanation. Furthermore, unlike the authors' claim, those changes had not previously been found in horse riders in the study by [START_REF] Wentz | Life on horseback: Palaeopathology of two Scythian skeletons from Alexandropol, Ukraine[END_REF]. Indeed, in this study, some pelvic indices (greater sciatic notch, subpubic concavity among others) are ambiguous regarding the sex diagnosis, which is probably due to the immaturity of the skeleton according to the authors. It should be noted that for most of scholars who associate the presence of traumas with the practice of horse riding, a fall from the horse is one of the main possible explanations.

Regarding foot traumas, another possible direct consequence of the contact with horses is the crushed foot, when being stepped on by horses (Willey, 1997) but also very likely if the horse falls directly on the rider's foot.

Although they did not perform direct anthropological observations, the study by [START_REF] Ki | Horse-riding accidents and injuries in historical records of Joseon Dynasty, Korea[END_REF] is of particular interest as they investigated Korean historical records (Joseon Dynasty)

for mentions and descriptions of horse riding-related accidents and injuries. They were mainly the result of a fall from a horse and occurred mostly at the extremities (lower in a higher frequency), the trunk, and head, in this order.

The description made by [START_REF] Wilczak | Consideration of sexual dimorphism, age, and asymmetry in quantitative measurements of muscle insertion sites[END_REF] on the remains of an individual who died at the Battle of the Little Bighorn (25 June 1876) is atypical. He noted the presence of "an exostosis near the proximal articular surface of the proximal end of the right proximal row hand phalanx II, most likely a healed dislocation or torn ligament" (p. 91). Willey comments the similarity of this lesion to a "cowboy thumb", which results from the fractures related to hanging onto or gripping a saddle horn while being thrown off a horse or a mechanical bull in rodeos [START_REF] Kennedy | Skeletal markers of occupational stress[END_REF]. Similarly, the paleopathological investigation performed by [START_REF] Dutour | Palaeopathological Study of Napoleonic Mass Graves Discovered in Russia[END_REF] on skeletal remains of Napoleonic soldiers of the Grande Armée (Russian Campaign of 1812), discovered in Kaliningrad, lead to suggest that the presence of healed fractures of the fifth fingers could be "due to the bridle being yanked out when curbing a horse" (p. 522). This army notably included soldiers from cavalry regiments.

We should also mention that [START_REF] Langlois | L'église de Notre-Dame-de-Bondeville et sa population (VIIe-IXe siècles, Seine-Maritime)[END_REF] attribute the presence of subperiosteal hematomas on femurs and tibias as being part of the "diagnostic" for horse riding.

Finally, some authors only mention an increased frequency of traumas in their sample of presumed riders, without being more specific [START_REF] Miller | The Effect of Horseback Riding on the Human Skeleton[END_REF]. Others refer to the presence of polytraumatism, an association of several fractures (clavicle, humerus, wrist, ribs, femur, tibia, fibula) as a possible consequence of horse riding [START_REF] Langlois | L'église de Notre-Dame-de-Bondeville et sa population (VIIe-IXe siècles, Seine-Maritime)[END_REF].

In addition to the five groups of skeletal changes that we reviewed here, another type of lesions was occasionally mentioned by some scholars as being related to the stress of horse riding: periostitis on the lower limbs and, in particular, the legs. Indeed, [START_REF] Reinhard | Identifying Equestrian Skeletal Markers[END_REF] present periostitis of the tibiae, assessed via radiography, as a skeletal indicator of equestrian life in Omaha skeletons dating between 1780 and 1820. [START_REF] Langlois | L'église de Notre-Dame-de-Bondeville et sa population (VIIe-IXe siècles, Seine-Maritime)[END_REF] note the presence of periostitis on the anterior or internal side of the femurs and tibias as part of the lesions that can be associated with horse riding. [START_REF] Pulcini | La necropoli di Olmo di Nogara (Verona). Studio paleobiologico dei resti umani per la ricostruzione dell[END_REF] describes, in skeletons from a Bronze Age necropolis in Verona, Italy, the presence of tibial periostitis as being due to the repetitive microtraumas that occur in horse riding. Similarly, she describes in three cases (old adults) the presence of ischial bursitis that could be attributed to horse riding for the same reason. [START_REF] Anđelinović | Skeleton changes induced by horse riding on medieval skeletal remains from Croatia[END_REF] also attribute periostitis on the lower extremities (tibia and fibula) of medieval skeletons from Croatia to frequent horse riding. Finally, [START_REF] Panzarino | Chi era e come viveva: profilo bioantropologico dell'uomo sepolto nella tomba 6[END_REF] presume that the presence of periostitis on the tibia and fibula can also be associated with the frequent and repetitive microtraumas during riding.

II.D.2. Main limitations for the identification of reliable horse riding-related skeletal changes

We presented here, in the form of synthetic tables (see II.D.1 above), a quasi-exhaustive review of the anthropological literature on horse riding-related skeletal changes (HRSC). The first conclusion that can be made from this review is that even though some changes are more often cited than others, there is no consensus on a set of skeletal changes that would allow to reliably identify this activity. While the mention of the same specific marker by numerous authors can give some credibility to it, it does not demonstrate its link with horse riding when authors simply make an observation and relate it to the activity based solely on previous research [START_REF] Baillif-Ducros | La pratique de la monte à cheval au haut Moyen Âge (fin Ve-VIIe siècle) dans le nord-est de la Gaule. État des connaissances archéologiques[END_REF]. Besides the early studies from the beginning of the 1990s [START_REF] Miller | The Effect of Horseback Riding on the Omaha and Ponca: Paleopathological Indications of European Contact[END_REF][START_REF] Pálfi | Traces des activités sur les squelettes des anciens Hongrois[END_REF], there are, in the end, only a few that really bring a contribution to the identification of HRSC, and even less are systematic studies (e.g., [START_REF] Erickson | Fourier analysis of acetabular shape in Native American Arikara populations before and after acquisition of horses[END_REF][START_REF] Garofalo | The osteologic markers of horseback riding: An examination of two medieval English populations[END_REF][START_REF] Eng | Nomadic Pastoralists and the Chinese Empire: A Bioarchaeological Study of China's Northern Frontier[END_REF][START_REF] Tichnell | Invisible Horsewomen: Horse Riding and Social Dynamics on the Steppe[END_REF][START_REF] Baillif-Ducros | La pratique de la monte à cheval au haut Moyen Âge (fin Ve-VIIe siècle) dans le nord-est de la Gaule. État des connaissances archéologiques[END_REF][START_REF] Djukic | Morphological appearance of muscle attachment sites on lower limbs: Horse riders versus agricultural population[END_REF][START_REF] Fuka | Activity markers and horse riding in Mongolia: Entheseal changes among Bronze and Iron Age human skeletal remains[END_REF].

II.D.2.a. Limitations related to the link between horse riding and the materials

The selection of a pertinent skeletal series is one of the most determinant methodological criteria for the reconstruction of activities in past populations (see I.C above). Unfortunately, there is no historical or modern reference collection of skeletons of horse riders and the selection of a pertinent sample represents, therefore, a major difficulty.

In some studies, the hypothesis of the presence of riders among the individuals relies only on the presence of skeletal changes previously discussed as being related to horse riding and is not supported by any evidence (e.g., [START_REF] Fornaciari | Paleopatologia del cimitero signorile del castello di Monte di Croce (Ia fase, XI secolo)[END_REF][START_REF] Langlois | L'église de Notre-Dame-de-Bondeville et sa population (VIIe-IXe siècles, Seine-Maritime)[END_REF]Robin, 2011;[START_REF] Bagagli | Horseman Syndrome" in the Tuscan Early Middle Age: The Sk888 Case[END_REF][START_REF] Simalcsik | Anthropological Analysis of the Human Osteological Remains Discovered in the Tumular Cemetery from Cernavodă -A2 Highway (Tumuli nos. 7, 7A, 7B)[END_REF]. In others, the archaeological, historical, or ethnological context suggests that the population investigated used to practice horse riding (e.g., [START_REF] Bradtmiller | The effect of horseback riding on Arikara arthritis patterns[END_REF][START_REF] Snow | Human Osteological Remains from the Battle of the Little Bighorn[END_REF][START_REF] Józsa | Enthesopathies (insertion tendopathies) as indicators of overuse of tendons and muscles in ancient Hungarian populations[END_REF][START_REF] Miller | The Effect of Horseback Riding on the Omaha and Ponca: Paleopathological Indications of European Contact[END_REF][START_REF] Sandness | Vertebral Pathology in Prehistoric and Historic Skeletons from Northeastern Nebraska[END_REF][START_REF] Molleson | A cart driver from Ur[END_REF][START_REF] Blondiaux | À propos de la dame d'Hochfelden et de la pratique cavalière : discussion autour des sites fonctionnels fémoraux[END_REF][START_REF] Molleson | Riders' Bones from Kish, Iraq[END_REF][START_REF] Courtaud | Osteomorphological features of nomadic riders: Some examples from Iron Age populations located in southwestern Siberia[END_REF][START_REF] Reinhard | Identifying Equestrian Skeletal Markers[END_REF][START_REF] Garofalo | The osteologic markers of horseback riding: An examination of two medieval English populations[END_REF][START_REF] Fornaciari | The Medici Project: First anthropological and paleopathological results of the exploration of the Medici tombs in Florence[END_REF][START_REF] Wentz | Life on horseback: Palaeopathology of two Scythian skeletons from Alexandropol, Ukraine[END_REF][START_REF] Tichnell | Invisible Horsewomen: Horse Riding and Social Dynamics on the Steppe[END_REF][START_REF] Dutour | Palaeopathological Study of Napoleonic Mass Graves Discovered in Russia[END_REF][START_REF] Serna | Osteobiografía de dos individuos inhumados durante la Campaña del Desierto: el caso del sitio Chimpay (Argentina)[END_REF][START_REF] Panzarino | Chi era e come viveva: profilo bioantropologico dell'uomo sepolto nella tomba 6[END_REF][START_REF] Djukic | Morphological appearance of muscle attachment sites on lower limbs: Horse riders versus agricultural population[END_REF][START_REF] Fuka | Activity markers and horse riding in Mongolia: Entheseal changes among Bronze and Iron Age human skeletal remains[END_REF][START_REF] Karstens | A palaeopathological analysis of skeletal remains from Bronze Age Mongolia[END_REF]. Depending on the quality of these contextual data, this may represent valuable information as the group as a whole can be considered as a riding population, which should logically lead to a higher prevalence of some HRSC compared to other presumed non-riding populations. However, such population-level contextual information still does not allow identifying which individuals, in particular, were riders and which were not, and, in that case, the influence of HRSC in the data may likely be diluted.

As discussed by [START_REF] Baillif-Ducros | La pratique de la monte à cheval au haut Moyen Âge (fin Ve-VIIe siècle) dans le nord-est de la Gaule. État des connaissances archéologiques[END_REF], the practice of horse riding must be attested by strong evidence, such as the presence of grave goods related to riding, in order to assure the reliability of the association between the skeletal changes and the activity. A possible exception to this point concerns rare cases of well-documented historical events that can lead to a reasonable interpretation of some skeletal changes in terms of activity. For instance, the presence of healed fractures, Schmorl's nodes, squatting facets, and Poirier's facets was assumed to be related to horse riding on the remains of individuals who arguably were soldiers from the Seventh Cavalry, who fought and died at the Battle of Little Bighorn on 25, June 1876, along with Lieutenant Colonel George A. Custer, during the American Civil and Indian Wars [START_REF] Wilczak | Consideration of sexual dimorphism, age, and asymmetry in quantitative measurements of muscle insertion sites[END_REF]. In the same way, the presence of modifications on the femoral neck and acetabula, and healed fractures of the long bones, were considered as a possible consequence of the practice of horse riding on skeletal remains of Napoleonic soldiers of the Grande Armée (Russian Campaign of 1812), discovered in Kaliningrad, Russia [START_REF] Dutour | Palaeopathological Study of Napoleonic Mass Graves Discovered in Russia[END_REF].

In a rather similar way, this exception may concern well-known historical figures such as King Philip II of Macedonia, father of Alexander the Great and renowned rider, whose remains have been presumably identified and show signs of horse riding according to the authors [START_REF] Bartsiokas | The lameness of King Philip II and Royal Tomb I at Vergina, Macedonia[END_REF]. The identification of the remains of historical figures is, however, always strongly debated, and this case is no exception.

While it must not be considered as absolute evidence, only the presence of archaeological items related to equestrian activity in the grave can, therefore, represent a robust indicator that one particular individual may have been a rider. Unfortunately, only a few studies explicitly mention the existence of a direct evidence associating the individuals and the riding practice in the funerary context [START_REF] Pap | A Dabas (Gyón)-paphegyi XI. századi embertani széria (The anthropological series of Dabas (Gyón)-paphegy from the 11th century)[END_REF]Pálfi et al., 1992b;Belcastro & Facchini, 2001;Belcastro et al., 2001;[START_REF] Uerpmann | Post-Neolithic Human Remains from the Jebel al-Buhais Area[END_REF][START_REF] Belcastro | Continuity or discontinuity of the life-style in central Italy during the Roman imperial age-early middle ages transition: Diet, health, and behavior[END_REF][START_REF] Üstündağ | A possible case of Scheuermann's disease from Akarçay Höyük, Birecik (Şanlıurfa, Turkey)[END_REF][START_REF] Aguayo | Variations in Skeletal Markers and Pathologies between Southern Plains Equestrian and Puebloan Native American Populations[END_REF][START_REF] Baillif-Ducros | Approche méthodologique pour distinguer un ensemble lésionnel fiable de la pratique cavalière. Exemple du squelette de la tombe 11 du site de « La Tuilerie » à Saint-Dizier (Haute-Marne), VIe siècle[END_REF][START_REF] Baillif-Ducros | Stirrups and archaeological populations: Bioanthropological considerations for determining their use based on the skeletons of two Steppe riders[END_REF][START_REF] Khudaverdyan | Multiple trauma in a horse rider from the Late Iron Age cemetery at Shirakavan, Armenia[END_REF][START_REF] Sarry | La sépulture multiple laténienne du site de Gondole (Le Cendre, Puy-de-Dôme)[END_REF][START_REF] Baillif-Ducros | La pratique de la monte à cheval au haut Moyen Âge (fin Ve-VIIe siècle) dans le nord-est de la Gaule. État des connaissances archéologiques[END_REF]. Among them, even fewer concern a sample of more than just one or a handful of presumed riders based on direct evidence [START_REF] Pálfi | Traces des activités sur les squelettes des anciens Hongrois[END_REF]Belcastro & Facchini, 2001;Belcastro et al., 2001;[START_REF] Belcastro | Continuity or discontinuity of the life-style in central Italy during the Roman imperial age-early middle ages transition: Diet, health, and behavior[END_REF][START_REF] Sarry | La sépulture multiple laténienne du site de Gondole (Le Cendre, Puy-de-Dôme)[END_REF][START_REF] Baillif-Ducros | La pratique de la monte à cheval au haut Moyen Âge (fin Ve-VIIe siècle) dans le nord-est de la Gaule. État des connaissances archéologiques[END_REF]. Studies with a sample size that do not allow the observation of a repetition of skeletal changes in several individuals and to perform a statistical analysis to test their significance can still provide valuable information, but these can be considered anecdotal in nature. In that case, indeed, we must acknowledge the possibility that the presence of certain changes on presumed riders' skeletons could be a mere coincidence. In that regard, the studies led by Belcastro and collaborators particularly stand out with a sample size of 13 presumed horsemen, with riding-related deposit in their graves, thus allowing a repetition of the observations and measurements (Belcastro & Facchini, 2001;Belcastro et al., 2001;[START_REF] Belcastro | Continuity or discontinuity of the life-style in central Italy during the Roman imperial age-early middle ages transition: Diet, health, and behavior[END_REF]. They notably identified different entheseal changes and morphological variants that could be related to this practice, with the support of the archaeological context, functional aspects, and the anthropological literature (Belcastro et al., 2001).

II.D.2.b. The lack of a comparison group

Only the analysis of comparative samples of known riders and non-riders, from the same group or similar populations, can lead to the identification of reliable skeletal changes associated with horse riding, as the most significant differences observed between them should, in that case, reflect the consequences of this specific activity [START_REF] Tichnell | Invisible Horsewomen: Horse Riding and Social Dynamics on the Steppe[END_REF]. Ideally, the main sample and the comparison group should indeed belong to the same population and the same period (i.e., genetically and culturally similar), in order to limit the introduction of external factors that could explain the possible differences observed (e.g., inter-population variability, differences in climate and geography, differences in lifestyles). This condition is, however, difficult or even impossible to respect in practice as a collection of clearly identified riders and non-riders from the same chrono-cultural context does not seem to exist in the archaeological record. Furthermore, the absence of riding-related archaeological elements is not enough to undoubtedly confirm that a population was not practicing this activity. The only certain cases of non-riding populations are prehistoric ones who lived before the domestication of the horse and later populations from territories where the horse was absent, such as Pre-Contact Native Americans, who lived before its reintroduction on the American continent by Europeans from the end of the 15th century.

In the end, despite this, a few scholars make a valuable effort to include a comparison group of presumed non-riders in their studies. The selection of the groups compared this way can rely on differences of lifestyles: nomadic pastoralists versus agricultural populations from Mongolia and China [START_REF] Eng | Nomadic Pastoralists and the Chinese Empire: A Bioarchaeological Study of China's Northern Frontier[END_REF], Pre-versus Post-Contact Arikara populations and Post-medieval British city-versus country-dwelling populations [START_REF] Tichnell | Invisible Horsewomen: Horse Riding and Social Dynamics on the Steppe[END_REF], or also a medieval Avar population versus a medieval agricultural population from Serbia [START_REF] Djukic | Morphological appearance of muscle attachment sites on lower limbs: Horse riders versus agricultural population[END_REF]. It should be noted that Miller and collaborators [START_REF] Miller | The Effect of Horseback Riding on the Omaha and Ponca: Paleopathological Indications of European Contact[END_REF][START_REF] Miller | The Effect of Horseback Riding on the Human Skeleton[END_REF][START_REF] Reinhard | Trade, contact, and female health in Northeast Nebraska[END_REF] also perform a comparison between a group of riders and non-riders in Post-Contact Native American Omaha and Ponca populations from Nebraska, but these two activity groups are identified only on the basis of the presence or absence of skeletal changes already considered as characteristic of horse riding. Some studies rely otherwise on the distinction between females and males within the same group (e.g., [START_REF] Tichnell | Invisible Horsewomen: Horse Riding and Social Dynamics on the Steppe[END_REF][START_REF] Ciurletti | Analisi biomeccanica del femore e del coxale per comprendere l'economia di sussistenza e il comportamento occupazionale legato all'uso del cavallo nella populazione della necropoli di Olmo di Nogara (Bronzo medio, Verona)[END_REF], assuming that riding was mostly an activity restricted to males. Historical sources tend in fact to attest that women who were riding horses generally belonged to a certain elite, such as during the Merovingian period, as described by Gregory of Tours, and that it mostly concerned parade riding, as attested by the generalized practice of riding sidesaddle for women since the 12th century (see [START_REF] Baillif-Ducros | La pratique de la monte à cheval au haut Moyen Âge (fin Ve-VIIe siècle) dans le nord-est de la Gaule. État des connaissances archéologiques[END_REF].

Nevertheless, in archaeological populations, the assumption that women were not riding, or less than males, often lacks arguments.

Finally, another relevant option is to compare, within the same population, individuals who are presumed riders on the basis of their grave goods (horse bones, riding equipment) with the individuals who lack such direct evidence. Although the latter ones are not necessarily considered as non-riders, the possible differences in observed skeletal changes may reflect the differences in grave deposits between the two subgroups, and thus, hypothetically reflect differences in the practice of horse riding. Even though their purpose is not precisely to identify horse riding-related skeletal changes, Belcastro & Facchini (2001) are the first to compare in an early medieval Italian series, a group of horsemen, whose identification is based on the presence of archaeological deposit in the graves of the individuals, with the group of males who did not have such riding-related deposit. This way, they compared the stature as well as several other cranial and post-cranial morphometric characteristics to discuss populational aspects. Belcastro and collaborators (2007), following a similar procedure, compared these horsemen again with the individuals from the same necropolis without riding-related deposit, and also with a Roman Imperial period series. This time, the focus was on the diet, health, and behavior of these populations. Later on, Baillif-Ducros (2018) studied five Merovingian series from northeastern Gaul, each of them including at least one individual with riding-related grave goods. Her statistical analyses of various skeletal changes notably included a comparison between the individuals with and without riding elements in the graves, although, depending on the feature and the state of preservation of the bones, the sample size for the individuals with riding equipment could be very reduced. Therefore, most of the criteria considered as promising indicators for riding (such as Poirier's facet, the ovalization of the acetabulum, joint changes at the hip, or some entheseal changes at the ischiopubic ramus) were identified from observations on all individuals from the Merovingian series of that study, and not only on the individuals with riding deposit (Baillif-Ducros, 2018).

II.D.2.c. Other methodological limitations

One of the main limitations in the study of HRSC is the lack of methodological considerations in the approach adopted by scholars. As mentioned previously, there are only a few studies with a pre-established methodology and the adoption of a systematic recording of quantitative or qualitative variables (such as presence/absence/not observable), which are determinant to allow performing statistical analyses and identifying reliable activity-related skeletal changes (e.g., [START_REF] Erickson | Fourier analysis of acetabular shape in Native American Arikara populations before and after acquisition of horses[END_REF][START_REF] Garofalo | The osteologic markers of horseback riding: An examination of two medieval English populations[END_REF][START_REF] Eng | Nomadic Pastoralists and the Chinese Empire: A Bioarchaeological Study of China's Northern Frontier[END_REF][START_REF] Tichnell | Invisible Horsewomen: Horse Riding and Social Dynamics on the Steppe[END_REF][START_REF] Baillif-Ducros | La pratique de la monte à cheval au haut Moyen Âge (fin Ve-VIIe siècle) dans le nord-est de la Gaule. État des connaissances archéologiques[END_REF][START_REF] Djukic | Morphological appearance of muscle attachment sites on lower limbs: Horse riders versus agricultural population[END_REF][START_REF] Fuka | Activity markers and horse riding in Mongolia: Entheseal changes among Bronze and Iron Age human skeletal remains[END_REF]. However, the variety of scoring methods and skeletal features investigated makes it difficult to compare the studies. We also noted that, in some cases, studies lack details regarding the nature and the localization of the skeletal changes mentioned (e.g., [START_REF] Fornaciari | The Medici Project: First anthropological and paleopathological results of the exploration of the Medici tombs in Florence[END_REF][START_REF] Simalcsik | Anthropological Analysis of the Human Osteological Remains Discovered in the Tumular Cemetery from Cernavodă -A2 Highway (Tumuli nos. 7, 7A, 7B)[END_REF][START_REF] Anđelinović | Skeleton changes induced by horse riding on medieval skeletal remains from Croatia[END_REF][START_REF] Serna | Osteobiografía de dos individuos inhumados durante la Campaña del Desierto: el caso del sitio Chimpay (Argentina)[END_REF][START_REF] Antikas | New Finds from the Cremains in Tomb II at Aegae Point to Philip II and a Scythian Princess[END_REF]. Some authors also present a list of changes assumed to be related to horse riding without explicitly mentioning which among them they actually observed in their samples [START_REF] Bagagli | Horseman Syndrome" in the Tuscan Early Middle Age: The Sk888 Case[END_REF].

Other limitations that we observed in the literature concern methodological aspects that have already been mentioned regarding the field of activity reconstruction (see I.C above).

While the comparison between female and male individuals from the same group can provide very valuable information related to societal organization and the sexual division of labor, sexual dimorphism can also affect different types of skeletal changes (e.g., [START_REF] Jurmain | Bioarchaeology's Holy Grail: The Reconstruction of Activity[END_REF][START_REF] Weiss | Sex differences in musculoskeletal stress markers: Problems with activity pattern reconstructions[END_REF][START_REF] Schrader | Activity, Diet and Social Practice. Addressing Everyday Life in Human Skeletal Remains[END_REF]. If both females and males are included in a sample, one cannot put aside the possibility that the differences observed between them do not necessarily reflect behavioral differences. Unfortunately, some studies are not cautious enough and fail to discuss this aspect before providing any interpretation in terms of activity (e.g., [START_REF] Miller | The Effect of Horseback Riding on the Omaha and Ponca: Paleopathological Indications of European Contact[END_REF]. Similarly, while it is acknowledged that older individuals are affected by higher frequencies of degenerative changes that can bias the analysis of activity-related markers (e.g., [START_REF] Weiss | Understanding muscle markers: Aggregation and construct validity[END_REF][START_REF] Weiss | Understanding muscle markers: Lower limbs[END_REF][START_REF] Alves Cardoso | Enthesopathy formation in the humerus: Data from known age-at-death and known occupation skeletal collections[END_REF][START_REF] Milella | The effect of age, sex, and physical activity on entheseal morphology in a contemporary Italian skeletal collection[END_REF], they are almost always present in the materials. Their inclusion in study samples is often inevitable and can sometimes be seen as a necessary "evil", in order to overcome problems related to age estimation or limited sample size, but the scholars must also, in that case, take this methodological bias into account in their discussion. Moreover, as discussed previously, pathological conditions responsible for entheseal changes, like DISH and spondyloarthropathies, can interfere when interpreting skeletal changes as being activityrelated (e.g., [START_REF] Dutour | Activités physiques et squelette humain : le difficile passage de l'actuel au fossile[END_REF][START_REF] Jurmain | Bioarchaeology's Holy Grail: The Reconstruction of Activity[END_REF][START_REF] Villotte | Understanding entheseal changes: Definition and life course changes[END_REF]. Only a small minority of studies address this matter (e.g., [START_REF] Pálfi | Traces des activités sur les squelettes des anciens Hongrois[END_REF], while most fail to mention how the data were handled in such situations (i.e., inclusion, partial or total exclusion). This issue also concerns, for instance, the presence of traumas that can affect the study of entheseal and joint changes, as well as metric analyses, in an individual.

Furthermore, as previously discussed, even though there are problems of transposition between the modern data from sports medicine and the activities performed in past populations, those data can still provide useful indicators of the possible lesions and changes resulting from an activity and give more credibility to, if not confirm, the association between a skeletal change and an activity [START_REF] Dutour | Activités physiques et squelette humain : le difficile passage de l'actuel au fossile[END_REF][START_REF] Dutour | Chasse et activités physiques dans la Préhistoire : les marqueurs osseux d'activités chez l'homme fossile[END_REF]. In this aspect, only a few studies refer to clinical and sports medicine literature to support the riding hypothesis (e.g., [START_REF] Blondiaux | À propos de la dame d'Hochfelden et de la pratique cavalière : discussion autour des sites fonctionnels fémoraux[END_REF][START_REF] Pálfi | Activity-induced skeletal markers in historical anthropological material[END_REF][START_REF] Baillif-Ducros | Approche méthodologique pour distinguer un ensemble lésionnel fiable de la pratique cavalière. Exemple du squelette de la tombe 11 du site de « La Tuilerie » à Saint-Dizier (Haute-Marne), VIe siècle[END_REF][START_REF] Djukic | Bone macromorphology at muscle attachment sites: Its relationship with the microarchitecture of the underlying bone and possible implications for the reconstruction of habitual physical activities of past populations[END_REF][START_REF] Baillif-Ducros | La pratique de la monte à cheval au haut Moyen Âge (fin Ve-VIIe siècle) dans le nord-est de la Gaule. État des connaissances archéologiques[END_REF]. In our review, we observed that if some of the skeletal changes mentioned by the authors can be viewed in relation to what sports medicine describes (such as spinal changes, extraspinal traumas, entheseal changes at the attachment sites of the muscles involved in riding), it is not the case for several of them, such as the hand phalanx inflammation considered to be related to holding the reins by [START_REF] Panzarino | Chi era e come viveva: profilo bioantropologico dell'uomo sepolto nella tomba 6[END_REF].

Finally, another limitation that impedes the ability to reach a reliable definition of a horse riding syndrome is the existence of various riding styles and equipment through cultures and eras, resulting in the possibility that there may not be any universal set of skeletal changes related to horse riding. Only a very few studies mention the potential impact of the riding style on the development of skeletal changes [START_REF] Eng | Morphometric analysis of acetabular rim shape among ancient Mongolian pastoralists[END_REF][START_REF] Tichnell | Invisible Horsewomen: Horse Riding and Social Dynamics on the Steppe[END_REF][START_REF] Eng | A bioarchaeological study of osteoarthritis among populations of northern China and Mongolia during the Bronze Age to Iron Age transition to nomadic pastoralism[END_REF][START_REF] Baillif-Ducros | La pratique de la monte à cheval au haut Moyen Âge (fin Ve-VIIe siècle) dans le nord-est de la Gaule. État des connaissances archéologiques[END_REF] 2018) also suggests that one should be looking for horse riding indicators specific to a chronological period in order to identify the presence of riders in a collection.

II.D.2.d.Implications for the identification of horse riding-related skeletal changes

Those numerous limitations result in a blurred vision regarding which skeletal changes should be considered as reliable and repeatable indicators of horse riding practice. On this basis, a study with the objective of identifying reliable HRSC should therefore at least  rely on a pertinent population with a well-documented archaeological, historical, or ethnological context that confirms the practice of horse riding;

 include an adequate-size sample of individuals from this population, ideally young and mature adults of the same sex, with direct archaeological evidence for the practice of horse riding (such as grave goods) in order to allow a repetition of the observations and comparisons, and to avoid methodological biases;

 use a precise methodology with a systematic recording of a large scale of qualitative and quantitative features for statistical analyses;

 discuss the validity of the observed skeletal changes in light of functional morphology (i.e., by referring to the riding position characteristics) and sports medicine data;

 cautiously deal with the data in case of pathological conditions that can affect the analysis of some activity-related changes (e.g., metabolic or inflammatory disorders for entheseal changes, traumatic lesions for entheseal and joint changes, and measurements); and

 include a comparison sample of known non-riders.

Research objectives

Our main objectives can be divided into two major aspects.

A bioanthropological contribution

Our first and major objective is to bring a methodological contribution to the field of activity-related skeletal markers by improving the identification, in anthropological collections, of one of the major activities in the past that was horse riding. Taking into consideration the limitations noted in previous studies, we performed an extensive macromorphological analysis of various types of bones changes as well as osteometric analyses using pertinent skeletal samples. We selected these skeletal changes and indicators taking into account anatomical and functional aspects, and the bioanthropological and sports medicine literature on horse riding.

We relied on a population from the Hungarian Conquest period. Historical and archaeological sources attest that powerful armies of archers mounted on horses conquered the Carpathian Basin at the end of the 9th century and the beginning of the 10th century [START_REF] Engel | The Realm of St Stephen. A History of Medieval Hungary[END_REF]. In many cemeteries from that period, we can frequently uncover pieces of archery and horse riding equipment, as well as horse bones, that were intentionally deposited in the graves [START_REF] Révész | The cemeteries of the Conquest period[END_REF]. The close association between these items and the skeletons, together with the well-known historical context, allows postulating that the concerned individuals practiced horse riding during their life. In that respect, this population is one of the most relevant for methodological investigations of activity-related skeletal changes, especially those regarding horse riding, which have been already identified in skeletal remains of medieval Hungarians [START_REF] Pap | A Dabas (Gyón)-paphegyi XI. századi embertani széria (The anthropological series of Dabas (Gyón)-paphegy from the 11th century)[END_REF][START_REF] Józsa | Enthesopathies (insertion tendopathies) as indicators of overuse of tendons and muscles in ancient Hungarian populations[END_REF][START_REF] Pálfi | Traces des activités sur les squelettes des anciens Hongrois[END_REF][START_REF] Pálfi | Activity-induced skeletal markers in historical anthropological material[END_REF].

We followed an approach previously applied in studies about skeletal changes related to archery and horse riding in particular (Belcastro & Facchini, 2001;[START_REF] Belcastro | Continuity or discontinuity of the life-style in central Italy during the Roman imperial age-early middle ages transition: Diet, health, and behavior[END_REF][START_REF] Thomas | Bioarchaeology of the middle Neolithic: Evidence for archery among early European farmers[END_REF][START_REF] Tihanyi | Investigation of Hungarian Conquest Period (10th c. AD) archery on the basis of activity-induced stress markers on the skeleton -preliminary results[END_REF], which provided promising results in an exploratory and preliminary investigation (Berthon et al., 2016b). The objective is to analyze the prevalence of the skeletal changes of various types and values of metric data according to the presence or absence of archaeological deposits related to the activity of interest in the graves. Specifically, through a comparison between two subgroups from a Hungarian Conquest period cemetery, those with and without a horse-related deposit, as well as with an out-sample group of nonriders, we test the hypothesis that the individuals associated with a funeral deposit practiced horse riding during their life and should, therefore, display skeletal changes associated with this practice.

In the end, we expect to distinguish a set of bone changes that could reliably be associated with the practice of riding a horse, thus allowing the identification of this practice in an archaeological population, even though the universality of those markers will have to be questioned.

On another note, we previously mentioned that the multifactorial etiology of the skeletal changes, and especially the entheseal changes, represents one of the main difficulties for their interpretation in terms of activity (see I.C above). As an exploratory project, we investigated the three-dimensional microarchitecture at the level of an enthesis. Using micro-CT acquisitions and 3D reconstructions of the canals of the cortical bone, we aimed to observe if microstructural variations could allow distinguishing entheseal changes related to activity and those related to other factors such as metabolic disorders. Such a distinction could contribute to improving the reconstruction of activities of past populations.

An ethnoarchaeological contribution

As a second main objective, we are also interested in ethnoarchaeological aspects, for a better understanding of the societies from the Hungarian Conquest period. The analysis of the link between the archaeological deposits in the graves and the skeletal changes may provide clarification on the significance of the funerary practices, and, in particular, on the extent of the symbolic value of the horse-related deposits. In fact, if the presence of such deposit in the grave does not represent indisputable evidence -but a sufficient one -for the practice of riding during life, its absence does not necessarily mean either that an individual was not a rider.

Finally, this doctoral research will be expanded to other collections from the Hungarian Conquest period, and the data acquired in this doctoral research will pave the way for further studies focusing, in particular, on females and adolescents, always taking into consideration the archaeological deposits. The information that will be provided by such research on the individuals will give an opportunity to shed light upon the organization of the societies from the Hungarian Conquest period.

The Hungarian Conquest period: historical and archaeological context Historical context

According to historical sources, the Hungarians, or Magyars, arrived in the Carpathian

Basin as an alliance of seven tribes led by prince Árpád at the end of the 9th century [START_REF] Róna-Tas | Hungarians and Europe in the early Middle Ages: An introduction to early Hungarian history[END_REF][START_REF] Engel | The Realm of St Stephen. A History of Medieval Hungary[END_REF]. Under the pressure of other nomadic populations from the east, they arrived from the Pontic steppes, where they were previously settled. The question of their origin remains, however, a debated discussion [START_REF] Türk | Towards a Classification of grave Types and Burial Rites in the 10th-11th Century Carpathian Basin (Some Remarks and Observations)[END_REF][START_REF] Neparáczki | Mitogenomic data indicate admixture components of Central-Inner Asian and Srubnaya origin in the conquering Hungarians[END_REF].

There is no contemporary Hungarian account of their arrival, so this event was mostly described by written sources produced by external cultures, or by Hungarian sources from later periods (13-14th centuries) [START_REF] Tóth | A magyar törzsszövetség politikai életrajza. A magyarság a 9-10[END_REF]. It is believed that the Hungarians started to occupy some territories in the Carpathian Basin as early as 894 following military interventions that involved the Byzantines, Franks, Moravians, and Bulgarians. It would, however, be in 895 or 896 that attacks from the Pechenegs and Bulgarians led the Hungarians to definitely leave their lands between the Don and the Danube for the Carpathian Basin (Róna-Tas, 1999). In the very few years that followed, Hungarians progressively took control of the entire region, while conducting raids into Christian kingdoms in the north and the west, as well as against the Muslims in the Iberian Peninsula, and the Byzantines in the east [START_REF] Engel | The Realm of St Stephen. A History of Medieval Hungary[END_REF]. These raids led the Hungarians as far as Saxony and the city of Bremen, the Atlantic coasts of France and Spain through Reims, Burgundy, the Pyrenees, and Catalonia, the Southern tip of Italy through Rome, and the Byzantine city of Constantinople. The Hungarian conquerors were unanimously described by other cultures (e.g., Muslims, Byzantines, Western Christians) as nomadic horse riders, with warriors using notably a saber, spear, and bow from horseback (Róna-Tas, 1999;

Engel, 2001) (Figure 3). Their use of long-distance shooting, surprise, and their incredible speed of action due to their nomadic fighting style represented a great advantage when facing heavier types of military forces, that were more common in Western territories, especially [START_REF] Engel | The Realm of St Stephen. A History of Medieval Hungary[END_REF][START_REF] Sandler | Ground Warfare: An International Encyclopedia[END_REF] (Figure 4).

It is only the overwhelming defeat at the Battle of Lechfeld against the German forces of King Otto I in August 955 that marked the end of the campaigns of the Hungarians, although raids to the Byzantine Empire continued until 970 [START_REF] Engel | The Realm of St Stephen. A History of Medieval Hungary[END_REF]. In 972, prince Géza, a greatgrandson of Árpád, was the leader of the Hungarians, and he tried to maintain peaceful relations with the neighbor powers, and especially with the Holy Roman Empire, paving the way to the substitution of the pagan beliefs of the Hungarian societies by the adoption of Christianity [START_REF] Engel | The Realm of St Stephen. A History of Medieval Hungary[END_REF][START_REF] Marcsik | Paleopathological changes in the Carpathian Basin in the 10th and 11th centuries[END_REF].

Finally, the Christian kingdom of Hungary was founded in the year 1000 or 1001, when

Stephen I (later known as Saint Stephen), son of Géza, was crowned king. The kingdom of Hungary remained one of the greatest powers of Europe during at least the next 500 years, until the Ottoman conquest in the 16th century [START_REF] Engel | The Realm of St Stephen. A History of Medieval Hungary[END_REF]. We should mention that the term "Conquest period" and "conquerors" literally describe the time and populations of the conquest of the Carpathian Basin itself, generally acknowledged to have started in 895, and have ended in 907, with the Battle of Pressburg [START_REF] Langó | Archaeological research on the conquering Hungarians: A review[END_REF].

However, these terms are usually associated, in archaeology, to a 100-120 year-long period of time, starting with the conquest and ending with the consolidation of the Christian kingdom of Hungary, hence mostly covering the 10th century and its populations [START_REF] Langó | Archaeological research on the conquering Hungarians: A review[END_REF]. This is the meaning that we will use in the rest of this dissertation. Similarly, we use the term "Hungarian"

referring to the populations of the 10th-century Carpathian Basin, and not necessarily to the ethnic identity of the individuals in the cemeteries, which may include a mixture of conqueror and autochthonous populations [START_REF] Langó | Archaeological research on the conquering Hungarians: A review[END_REF].

The cemeteries and populations from the Conquest period: archaeological context

Written sources mention that after settling in the Carpathian Basin in the years following the conquest, the tribal alliance formed an independent state that controlled the Basin and its surrounding areas through military force. The local populations were not eradicated but seem to have been integrated, resulting in the emergence of a new and coherent material culture, that differed from the preceding periods [START_REF] Langó | Archaeological research on the conquering Hungarians: A review[END_REF].

Even though the archaeological investigations of settlement sites are of great importance to provide information on the societies from the Conquest period [START_REF] Visy | Hungarian Archaeology at the Turn of the Millennium[END_REF], the main archaeological sources of the period are provided by the numerous cemeteries that were excavated across the Carpathian Basin [START_REF] Révész | The cemeteries of the Conquest period[END_REF]. Around 30 000 burials have been excavated from cemeteries that were mostly in use from the time after the conquest until the 11th or even 12th century [START_REF] Langó | Archaeological research on the conquering Hungarians: A review[END_REF]. The archaeological goods found in the graves in association with the individuals are still used to identify different levels of social status [START_REF] Révész | A Kárpát-medence 10-11. századi temetőinek kutatása napjainkban (Módszertani áttekintés)[END_REF]. The presence of elements of saber, axe, quiver, composite bow, and arrowheads may, for instance, be linked to warriors (Figure 5), while notable or distinguished individuals (males or females) may have been buried with rich costume and braid ornaments, jewelry, belt sets, or, in some cases, an ornated sabretache (Figure 6 and 7a). Weapons and riding elements (e.g., plates and mounts of saddle, bits, harnesses, stirrups) could also be richly ornamented [START_REF] Engel | The Realm of St Stephen. A History of Medieval Hungary[END_REF][START_REF] Révész | The cemeteries of the Conquest period[END_REF] (Figure 8). Some are also buried with horses or with artifacts symbolizing the animal [START_REF] Engel | The Realm of St Stephen. A History of Medieval Hungary[END_REF]) (Figure 7b). Horses were killed and skinned in such a manner that the skull and leg bones were left in the hide, which was usually folded or spread out beside the deceased (Figure 5). This practice of partial horse burials was observed in several Conquest period cemeteries [START_REF] Révész | The cemeteries of the Conquest period[END_REF][START_REF] Langó | Reconstruction and 3D-modelling of a unique Hungarian Conquest period (10th century AD) horse burial[END_REF][START_REF] Vörös | Adatok a honfoglalás kori lovastemetkezésekhez[END_REF]. Examples of particularly rich cemeteries are notably provided by the three cemeteries of Karos, in northeastern Hungary, located between the Tisza and Bodrog rivers (Révész, 1996a[START_REF] Révész | The cemeteries of the Conquest period[END_REF] (Figure 5 and6). The cemeteries from the Conquest period are also characterized by the presence of graves without warrior and horse riding attributes, or rich goods. This variety of archaeological material discovered in cemeteries is due to different social, regional, populational, and chronological factors [START_REF] Révész | The cemeteries of the Conquest period[END_REF][START_REF] Langó | Archaeological research on the conquering Hungarians: A review[END_REF][START_REF] Révész | A Kárpát-medence 10-11. századi temetőinek kutatása napjainkban (Módszertani áttekintés)[END_REF]. [START_REF] Nepper | Hajdú-Bihar megye 10-11. századi sírleletei I-II. (Magyarország honfoglalás és kora Árpád-kori sírleletei 3)[END_REF]. These included, in particular, pieces of archery equipment (antler bow plates, quivers, arrowheads) and horse riding equipment (stirrups, bits, girth buckles, saddles; Figure 10).

Several graves also contained horse bones (skull and extremities), that were, in some cases, folded inside the horsehide before being deposited in association with the individuals (Figure 11). Based on the grave goods, the period of use of the cemetery was estimated to be during the 10th century CE.

In Sárrétudvari-Hízóföld, 262 graves from that period provided a total of 265 individuals that were previously examined by [START_REF] Oláh | Sárrétudvari-Hízóföld honfoglalás kori temetőjének történeti embertani értékelése[END_REF] and [START_REF] Pálfi | Traces des activités sur les squelettes des anciens Hongrois[END_REF][START_REF] Pálfi | Maladies dans l'Antiquité et au Moyen-Âge. Paléopathologie comparée des anciens Gallo-Romains et Hongrois[END_REF][START_REF] Pálfi | Activity-induced skeletal markers in historical anthropological material[END_REF].

According to these studies, the population is composed of 101 subadults, under the age of 20

(including 3 fetuses), 162 adults and 2 indeterminate individuals. A comprehensive paleopathological analysis had been carried out on the entire series, providing valuable results regarding the infectious diseases and the activity-related skeletal markers in particular [START_REF] Pálfi | Activity-induced skeletal markers in historical anthropological material[END_REF][START_REF] Pálfi | Maladies dans l'Antiquité et au Moyen-Âge. Paléopathologie comparée des anciens Gallo-Romains et Hongrois[END_REF].

Sárrétudvari-Hízóföld was selected as our main Hungarian collection among several other cases from the period for the following reasons: a) it was exhaustively excavated, well documented and published; b) it is one cemetery with the largest amount of archaeological remains that can be related to the practice of the mounted archers; c) the size of the population (see above); d) the state of preservation of the skeletons (between medium and good) was better than other samples from the 10th century; and, e) it is a series in which were originally identified the signs of a "Horse Riding Syndrome" in several individuals [START_REF] Pálfi | Traces des activités sur les squelettes des anciens Hongrois[END_REF][START_REF] Pálfi | Activity-induced skeletal markers in historical anthropological material[END_REF][START_REF] Pálfi | Maladies dans l'Antiquité et au Moyen-Âge. Paléopathologie comparée des anciens Gallo-Romains et Hongrois[END_REF]. Furthermore, the human skeletons from Sárrétudvari-Hízóföld are readily available for research, hosted in the anthropological collection of the Department of Biological Anthropology of the University of Szeged, Hungary, one of the largest in Europe [START_REF] Pap | The Routledge Handbook of Archaeological Human Remains and Legislation: An International Guide to Laws and Practice in the Excavation and Treatment of Archaeological Human Remains[END_REF]. Selection of the samples from the Hungarian Conquest period

I.B.1. Methodological considerations

Keeping in mind the numerous limitations mentioned by the scholars for the reconstruction of activities (e.g., [START_REF] Dutour | Activités physiques et squelette humain : le difficile passage de l'actuel au fossile[END_REF][START_REF] Jurmain | Bioarchaeology's Holy Grail: The Reconstruction of Activity[END_REF], we included in this study only adult males. Sex is indeed an important factor that can influence how the bone adapts in response to activity. The differences observed between a group of females and a group of males might be due, for instance, to sexual dimorphism in body size and hormonal changes during puberty [START_REF] Wilczak | Consideration of sexual dimorphism, age, and asymmetry in quantitative measurements of muscle insertion sites[END_REF]Niinimäki, 2012a;[START_REF] Weiss | Sex differences in musculoskeletal stress markers: Problems with activity pattern reconstructions[END_REF]. Furthermore, adolescents (even late ones) might present various traits related to developmental changes that could bias the comparisons. The decision of strictly focusing on adult males only results in samples of smaller sizes, but, in the frame of the methodological aspect of this research, it is a solution to limit the influence of non-mechanical factors in the results.

I.B.2. Reassessment of the sex of the individuals

We decided to reassess the sex that was previously determined, using more recent, reliable and accurate methodology. The coxal bone is the most relevant one for sex determination because of its marked sexual dimorphism resulting mainly from adaptive and functional constraints related to locomotion and childbearing. Furthermore, this sexual dimorphism is nonspecific for populations, unlike other ones [START_REF] Bruzek | Identification biologique individuelle en paléoanthropologie. Détermination du sexe et estimation de l'âge au décès à partir du squelette[END_REF][START_REF] Murail | DSP: a tool for probabilistic sex diagnosis using worldwide variability in hip-bone measurements[END_REF]. We applied in a complementary way the Probabilistic Sex Diagnosis, or DSP, recently revalidated as DSP2 [START_REF] Murail | DSP: a tool for probabilistic sex diagnosis using worldwide variability in hip-bone measurements[END_REF][START_REF] Bruzek | Validation and reliability of the sex estimation of the human os coxae using freely available DSP2 software for bioarchaeology and forensic anthropology[END_REF] and the macromorphological visual method developed by [START_REF] Bruzek | A method for visual determination of sex, using the human hip bone[END_REF]. Sex determination with these methods yields an accuracy rate close to 100 % and 98 %, respectively, in their reference samples. The first one, the DSP, is a metric method that relies on a combination of four to ten variables measured on the coxal bone, depending on its preservation. It has the great advantage of being based on a worldwide reference sample composed of more than 2000 individuals of known sex from 12 populations. The posterior probability of being female or male is calculated based on the linear discriminant analysis, and 0.95 is used as the threshold for sex classification, under which sex was not assigned [START_REF] Bruzek | Validation and reliability of the sex estimation of the human os coxae using freely available DSP2 software for bioarchaeology and forensic anthropology[END_REF]. The second method involves the precise visual scoring on the coxal bone of five morphological features (with three subcriteria for three of them), possible even on fragmentary bones. The binary scoring (present/absent), along with an intermediate category, limits subjectivity compared to more classical ordinal scales of evaluation. Sex assessment follows the majority rule, with a reliability of 95 % [START_REF] Bruzek | A method for visual determination of sex, using the human hip bone[END_REF].

Following these methods, we were able to reliably determine the sex of 121 individuals, including 7 subadults who were mature enough to perform a sex diagnosis. They included 52

females and 69 males.

The sex diagnosis that we performed, based on the complementary use of a macromorphological visual method and a metric probabilistic method, can be considered as strongly reliable [START_REF] Bruzek | A method for visual determination of sex, using the human hip bone[END_REF][START_REF] Murail | DSP: a tool for probabilistic sex diagnosis using worldwide variability in hip-bone measurements[END_REF][START_REF] Bruzek | Validation and reliability of the sex estimation of the human os coxae using freely available DSP2 software for bioarchaeology and forensic anthropology[END_REF]), but several individuals remained indeterminate, mostly because of a poor preservation of the coxal bones. As an attempt to increase the number of adult male individuals in our sample, we had the opportunity to benefit from the results of a genetic analysis performed on several individuals from the cemetery of Sárrétudvari-Hízóföld by the members of the Department of Genetics of the University of Szeged, Dr. Tibor Török and Dr. Endre Neparáczki. This analysis notably aimed at a better understanding of the origins of the Hungarian Conquerors (e.g., [START_REF] Neparáczki | Genetic structure of the early Hungarian conquerors inferred from mtDNA haplotypes and Y-chromosome haplogroups in a small cemetery[END_REF][START_REF] Neparáczki | Mitogenomic data indicate admixture components of Central-Inner Asian and Srubnaya origin in the conquering Hungarians[END_REF]. Those data concerned 25 individuals from the cemetery, for which the sex diagnosis methods had been applied, as well as 10 subadults for which the sex could not be determined from a macroscopic analysis of the bones as they were too young.

Regarding 22 individuals, we were able to determine the sex during our examination of the coxal bones and the genetic data confirmed our sex diagnosis in all cases (100%; 17 males and 5 females). The remaining three individuals had been considered as indeterminate adults as sex determination was not possible during our study due to a limited preservation or the absence of coxal bones. With the help of genetic data, these three individuals were proved to be females.

Thus, we were not able to identify more male individuals to be included in our samples.

However, the perfect correlation between the sex determined during our macroscopic analysis of the coxal bones and the sex identified via genetics confirms the reliability of the sex diagnosis methods that were used. This way, we can conclude that our selection of a male sample in the archaeological samples confidently excludes or strongly limits possible biases related to sex differences.

I.B.3. Reassessment of the age-at-death of the individuals

Age-at-death was also reassessed with more recent and reliable methodology. Bearing in mind the important variations regarding the maturation age of the skeleton [START_REF] Scheuer | The Juvenile Skeleton[END_REF], the distinction between the adult individuals (considered to be 20 years of age or over)

and the subadults was based on the following chosen criteria: the achieved maturation of the long bones (apart from the sternal extremity of the clavicle, as in the case of the iliac crest on the coxal bone), and the complete fusion of the epiphyseal rings of the vertebrae and the sphenooccipital synchondrosis [START_REF] Bruzek | Identification biologique individuelle en paléoanthropologie. Détermination du sexe et estimation de l'âge au décès à partir du squelette[END_REF]. Following these criteria, two out of the 69 male individuals were considered as subadults (late adolescents) and were therefore excluded from the sample for the analyses.

We attempted then to split the adults into age categories, to distinguish, especially, the young and mature adult individuals (YMA), between 20 and 49 years of age, and the older adult ones, above 50 years of age. This distinction is determinant for the analysis of the entheseal changes and joint changes in particular, as they are strongly influenced by age (see Chapter 1, I.C).

As a first step, the absence of fusion or the incomplete fusion of either the iliac crest of the coxal bone or the medial extremity of the clavicle, or both, was used for the identification of young adults, who died between 20 and 29 years of age, specifically [START_REF] Owings-Webb | Epiphyseal union of the anterior iliac crest and medial clavicle in a modern multiracial sample of American males and females[END_REF][START_REF] Kreitner | Bone age determination based on the study of the medial extremity of the clavicle[END_REF][START_REF] Coqueugniot | Brief communication: Infracranial maturation in the skeletal collection from Coimbra, Portugal: New aging standards for epiphyseal union[END_REF][START_REF] Schaefer | Juvenile osteology: A laboratory and field manual[END_REF] (Appendix 8).

As a second step, we relied on the changes at the sacropelvic surface of the ilium following the method proposed by [START_REF] Schmitt | Une nouvelle méthode pour estimer l'âge au décès des adultes à partir de la surface sacro-pelvienne iliaque[END_REF], which is different from the more classically used one proposed by [START_REF] Lovejoy | Chronological metamorphosis of the auricular surface of the ilium: A new method for the determination of adult skeletal age at death[END_REF]. It is based on a simple scoring system of four independent features (transverse organization, modification of the articular surface, apical modification, and modification of iliac tuberosity) that aims to limit the intra-and interobservers error. It relies on a large reference sample (N = 621), and the probability of belonging to a chronological interval depends on the combination of the scores of the four features and is calculated through the Bayesian approach, with a minimum overall probability of 80%. When the two sides were fully observable and provided a different estimation, both chronological intervals were combined to obtain a reliable but larger estimation. When one of the four criteria was not observable, the chronological intervals obtained for each of the possible combinations of scores were also combined. When three features only could be observed on one side while the other side was fully observable (i.e., all four features), the results obtained from the latter one were preferred. This method results in reliable age estimation, although not very precise, with, in many cases, large chronological intervals [START_REF] Schmitt | Une nouvelle méthode pour estimer l'âge au décès des adultes à partir de la surface sacro-pelvienne iliaque[END_REF][START_REF] Baccino | Determination of Adult Age at Death in the Forensic Context[END_REF].

Furthermore, poor preservation of the coxal bones may also greatly limit the results of the age estimation. It was thus common in our study that the resulting chronological intervals did not allow precisely categorizing the subjects. Instead, several individuals could only be identified as mature or old adults, above 30 years of age, while others could only be considered as indeterminate adults, who died above 20 years of age. In the end, 37 out of the 67 adult males could be categorized as young and mature adults (Appendix 8).

I.B.4. Composition of the samples of early Hungarians based on the archaeological deposits

In Sárrétudvari-Hízóföld, 32 graves presented an archaeological deposit that we can assume to be related to horse riding -either equipment or horse bones, or both. Based on the reassessed sex and age-at-death of the individuals, as explained above, there are at least 17 adult males within this group (RD = "Riding Deposit") (Appendix 1, 2). The other individuals, which

were not included in the study, are 1 female adult, 6 adults of indeterminate sex (one was not available during the study), 7 subadults and 1 unidentified individual (either a subadult or an adult).

In contrast, 50 individuals identified as adult males did not have any equipment related to horse riding or horse bones in their graves (NRD = "no Riding Deposit").

The results of the sex diagnosis performed on the 67 individuals from the RD and NRD groups are given in Appendix 5, 6, and 7.

The age estimation allowed categorizing the individuals in each group, as summarized in

Out-sample comparison: the documented collection of Lisbon Why a comparative sample?

Even if the archaeological data are determinant for the association between the skeletal markers and the activities, some limitations must be kept in mind. In our case, the sample of individuals from the Conquest period is divided into two sub-samples based on the presence or absence of deposit related to horse in the graves of the individuals, the hypothesis being that the ones without deposit (NRD) may not have practiced horse riding, or maybe to a lesser extent than the others (RD). However, caution is recommended as we must consider the possibility that the funerary deposits might have only a symbolic function and not be related with the actual practice of riding during the life of individuals. Therefore, the distinction between the two groups might not reflect the reality of the presence or absence of horse riders. Furthermore, all elements originally deposited in the graves might not have been preserved (e.g., taphonomic processes, disappearance of organic materials, lootings). Thus, it must be acknowledged that some individuals who initially had a deposit in their grave may have finally been included in the NRD group. For these reasons, a third group, with a clear and reliable context, is determinant to allow multiple comparisons that could clarify our understanding concerning both the methodological and the ethnoarchaeological aspects.

Selection of a collection

We selected an extra-group for which the intensive and regular practice of horse riding was highly improbable. It allowed first to compare each group in the Hungarian collection with this extra-group of non-riders, to observe the similarities or the differences between them, and it also allowed, secondly, to compare the early Hungarians as one group with the extra-group nonriders. As explained previously, if the distinction between the two sub-groups of Hungarians would not reflect the reality of the presence and absence of riders among them, it is however logical to expect that the semi-nomadic population of Hungarians as a whole should present more skeletal changes related to horse riding than the extra-group of non-riders.

In order to limit biases related to interpopulational variations, the most appropriate population for this comparison study would certainly be a medieval Hungarian one with the evident absence of the practice of horse riding. However, such population might simply not exist as the use of horses was very widespread in medieval Hungary. One viable option would have been to study prehistoric samples, preceding the domestication of the horse. This choice would have required to select samples from various collections in order to reach a satisfying number of individuals and would have, therefore, resulted in a non-homogenous sample.

Furthermore, the preservation of such prehistoric skeletal remains, usually being rather poor, would have strongly limited the observations.

Among the limited possibilities remaining available for our purpose, we chose to use a European documented skeletal collection, with a known socio-cultural context. Due to the valuable data associated with the individuals, such documented or identified skeletal collections have been used for numerous methodological studies regarding especially the estimation of the age at death, sex determination, diseases, and the activities (e.g., [START_REF] Coqueugniot | Brief communication: Infracranial maturation in the skeletal collection from Coimbra, Portugal: New aging standards for epiphyseal union[END_REF][START_REF] Perréard Lopreno | Adaptation structurelle des os du membre supérieur et de la clavicule à l'activité : analyse de l'asymétrie des propriétés géométriques de sections transverses et de mesures linéaires dans une population identifiée[END_REF][START_REF] Alves Cardoso | A portrait of gender in two 19th and 20th century Portuguese populations: a palaeopathological perspective[END_REF]Coqueugniot et al., 2010b;[START_REF] Villotte | Enthesopathies as occupational stress markers: Evidence from the upper limb[END_REF][START_REF] Niinimäki | What do muscle marker ruggedness scores actually tell us[END_REF]Alves Cardoso & Henderson, 2013;[START_REF] Milella | Exploring the relationship between entheseal changes and physical activity: A multivariate study[END_REF][START_REF] Bruzek | Validation and reliability of the sex estimation of the human os coxae using freely available DSP2 software for bioarchaeology and forensic anthropology[END_REF].

Bearing in mind the potential limits that this involves concerning inter-populational variability, in particular, we believed it still represents a valid alternative that can provide input to the discussion on the link between bone changes and horse riding.

The documented collection of Lisbon

II.C.1. Presentation of the collection

We used the Luís Lopes Skeletal Collection, curated in the National Museum of Natural History and Science (MUHNAC), in Lisbon. It is composed of 1692 skeletons with information regarding, among others, the sex, age at death, cause of death, and the occupation of the individuals [START_REF] Cardoso | Brief communication: The collection of identified human skeletons housed at the Bocage Museum (National Museum of Natural History), Lisbon, Portugal[END_REF]Alves Cardoso & Henderson, 2013). They were mostly Portuguese people who lived in Lisbon and who were born and had died between 1805 and 1975. The majority of the individuals in our sample mainly lived during the first half of the 20th century (average year of birth = 1900; average year of death = 1940), in an important urban area, with electricity and modern means of transport. This fact makes it very unlikely that they were practicing horse riding in an intensive way and on a daily basis, as was the case for our seminomadic Hungarians. They are therefore assumed to be a non-riding population.

II.C.2. Selection of the sample

To be consistent with the selection performed in the Hungarian collection, we included in this study only skeletons with a completed bone maturation, apart from the iliac crest and the sternal extremity of the clavicle, which still might be in a state of incomplete fusion. These are, indeed, usually among the last epiphyses to fully achieve their maturation, which can occur until the age of about 25 for the iliac crest and 29 or more for the medial clavicle (e.g., [START_REF] Bruzek | Identification biologique individuelle en paléoanthropologie. Détermination du sexe et estimation de l'âge au décès à partir du squelette[END_REF][START_REF] Coqueugniot | Brief communication: Infracranial maturation in the skeletal collection from Coimbra, Portugal: New aging standards for epiphyseal union[END_REF][START_REF] Schaefer | Juvenile osteology: A laboratory and field manual[END_REF].

Among the available adult males, we selected only individuals whose occupation was known, and we attempted to select among them mostly individuals who can be considered as having been generally physically "active" and to exclude those who presumably had a rather limited level of physical activity during their life (e.g., office worker, student, etc.) (Appendix 3). A comparison between the semi-nomadic Hungarians, known to have participated in many conflicts during the Conquest period, and a modern sample of individuals with a minimum of physical activity would probably result in very weak information regarding the influence of horse riding on the bones. Indeed, the presence of various non-specific changes might simply reveal that the Hungarians had more physical activity than the individuals from the modern sample.

While the occupation title is not an absolute evidence of what precise gestures the individuals performed on a daily basis, it still represents a rather good indicator of the fact that people had more or fewer chances to have had a rather high or low level of physical activity during their life. However, we stress that we did not attend to perform a precise categorization of the occupations, based, for instance, on criteria such as the preferential use of the muscles of the upper or lower limbs, the intensity, the repeatability of the gestures, or the specialization.

One reason was that the comparison sample needed to be used not only in the frame of this study concerning horse riding but also for a parallel investigation of archery-related markers, which focuses mostly on the upper limb and raises different questions. Furthermore, a distinction between the occupations following such criteria as mentioned above would have resulted in too little sample sizes. Finally, the information that is available is the occupation at the time of death, but we ignore, in most cases, the conditions in which the individuals were living as children, for how long they had that occupation, or if they changed it during their life.

It has been demonstrated that the categorization of occupation can represent a source of bias for the study of activities (Alves Cardoso & Henderson, 2013;[START_REF] Perréard Lopreno | Categorization of occupation in documented skeletal collections: Its relevance for the interpretation of activity-related osseous changes[END_REF].

Following those methodological considerations, we selected in the collection a sample composed of 47 adult males, aged 20 and older. The state of preservation of the bones was between good and excellent.

Again, to be consistent with the selection performed in the Hungarian collection, the age estimation method (see I.B.3 above) was also performed on the individuals from the documented collection of Lisbon (Table 7), and the results were compared with the known ageat-death (Table 8). It has to be noted that for the age estimation in the documented collection, we used the table of distribution of the posterior probabilities computed from a reference population whose age distribution is uniform, while we used the table of distribution of the posterior probabilities computed from a reference population whose age distribution corresponds to a life expectancy at birth of 30 years in the case of the archaeological samples [START_REF] Schmitt | Une nouvelle méthode pour estimer l'âge au décès des adultes à partir de la surface sacro-pelvienne iliaque[END_REF]. This was because the selection of the sample from the documented collection was based on specific criteria (sex, age, occupation), and is, therefore, not supposed to represent a natural population. In particular, there was no individual above 56 years of age in our selected sample. Out of a total of 47 individuals, the known age was included within the estimated age interval for 44 of them (93,6%). It can furthermore be noted that, regarding the remaining three, one was estimated to be more than 40 years of age while the known age was 35, while the age of the two others was just one year above the limit of the estimated interval (30 instead of 20-29 years, and 50 instead of 20-49 years of age). We can, therefore, consider that the age estimation based on the changes at the sacropelvic surface of the ilium [START_REF] Schmitt | Une nouvelle méthode pour estimer l'âge au décès des adultes à partir de la surface sacro-pelvienne iliaque[END_REF] was reliable in the documented sample.

Based on that observation, we decided not to use the estimated age but the known age in the documented collection for the selection of a group of young and mature adults to be compared with the young and mature adults identified in the archaeological groups. The sample size of the comparative group was, this way, larger for the analysis of entheseal and joint changes (i.e., 32 young and mature adults, identified with the known age, instead of 13 young and young or mature adults identified on the basis of the age estimation).

Methods for the study of horse riding-related skeletal changes

Macromorphological analyses

III.A.1. Entheseal changes

Many entheseal changes (EC) of the lower limb were associated with the practice of horse riding in anthropological literature (see Chapter 1, II.D.1). We previously discussed how EC are used as activity-related skeletal changes and their limitations, including the heterogeneity of the scoring methods (see Chapter 1, I.B and I.C). Considering that recent studies revealed that the correlation between EC and activity was not straightforward, and especially, that currently proposed scoring methods seem to be not efficient enough to reflect activity (e.g., [START_REF] Niinimäki | The relationship between intensity of physical activity and entheseal changes on the lower limb[END_REF][START_REF] Djukic | Bone microarchitecture at muscle attachment sites: The relationship between macroscopic scores of entheses and their cortical and trabecular microstructural design[END_REF][START_REF] Michopoulou | Evaluating the efficiency of different recording protocols for entheseal changes in regards to expressing activity patterns using archival data and cross-sectional geometric properties[END_REF][START_REF] Michopoulou | A Test of the Effectiveness of the Coimbra Method in Capturing Activity-induced Entheseal Changes[END_REF], we applied a simple binary scoring method. We relied on the widely used method

proposed by [START_REF] Villotte | Connaissances médicales actuelles, cotation des enthésopathies : nouvelle méthode[END_REF][START_REF] Villotte | Enthésopathies et activités des hommes préhistoriques. Recherche méthodologique et application aux fossiles européens du Paléolithique supérieur et du Mésolithique[END_REF], which was later simplified from a three-grade scale to a binary scoring method, with minor and major changes combined into a "present" score [START_REF] Villotte | Enthesopathies as occupational stress markers: Evidence from the upper limb[END_REF]. This simplification has also been recommended and applied by others (Alves [START_REF] Alves Cardoso | Enthesopathy formation in the humerus: Data from known age-at-death and known occupation skeletal collections[END_REF][START_REF] Ponce | A comparative study of activity-related skeletal changes in 3rd-2nd millennium BC coastal fishers and 1st millenium AD inland agriculturists in Chile, South America[END_REF][START_REF] Niinimäki | The relationship between intensity of physical activity and entheseal changes on the lower limb[END_REF]. It notably contributes to decrease subjectivity and thus to increase inter-and intraobserver agreement and facilitate comparisons. More detailed scoring methods, such as the new Coimbra method (Henderson et al., 2017b) propose a precise scoring of different features with the division of the enthesis into two zones, the margin, and surface. This distinction requires, however, precise knowledge regarding the anatomy of the entheses and the authors provide, so far, description for only a few of them. In addition, this method focuses only on fibrocartilaginous entheses, while a simple binary scoring can allow using fibrocartilaginous and fibrous entheses in the same analysis [START_REF] Niinimäki | The relationship between intensity of physical activity and entheseal changes on the lower limb[END_REF].

As mentioned previously (see Chapter 1, I.C), it was suggested that EC at fibrocartilaginous entheses provide more reliable results as they are more correlated with activity than those at fibrous entheses, for which the normal aspect and limits are less well understood (e.g., [START_REF] Villotte | Understanding entheseal changes: Definition and life course changes[END_REF]. Our investigation of horse riding-related skeletal changes notably aims to confirm if the skeletal changes mentioned in literature for several decades can be considered as reliable indicators for the practice of horse riding. It appears that several entheses that are referred to be part of the "horse riding syndrome" are fibrous entheses located on the diaphysis of the femur and tibia, in particular (see Chapter 1, II.D.1). These entheses are origin and insertion sites of muscles that are important in the practice of horse riding [START_REF] Willson | The riding muscles and their function in riding[END_REF], and they were also used in recent studies focusing on horse riders [START_REF] Djukic | Morphological appearance of muscle attachment sites on lower limbs: Horse riders versus agricultural population[END_REF]. Besides, a study by [START_REF] Niinimäki | The relationship between intensity of physical activity and entheseal changes on the lower limb[END_REF] provides an example where both types of entheses were included, and this factor did not have any influence on the results. In that regard, we included both fibrocartilaginous and fibrous entheses in our analysis of EC.

The function of the muscles attached to the entheses was the first criterion for their selection. We included indeed only entheses related to muscles that cover a wide range of movements involved in the position of the rider, contributing to control, coordination, and stabilization [START_REF] Willson | The riding muscles and their function in riding[END_REF][START_REF] Mcgrath | A review of the archaeological and sports medicine literature to determine the biomechanical markers of equestrian activity[END_REF]. The second criterion for the selection of entheses was, as mentioned above, their repeated mention in the anthropological literature as markers related to horse riding, in order to confirm or invalidate their pertinence in this respect. In addition, for more reliability, we mainly focused on entheses that were frequently mentioned, described, and scored in the literature on EC, and especially in methodological studies. This led, for instance, to the exclusion of several entheses located on the coxal bone. Entheses for which scoring appeared to problematic (due to a difficulty to distinguish normal and changed aspects, for instance), were also avoided. It was the case of the origin sites of the medial and lateral heads of the gastrocnemius muscle.

In the end, we selected 13 entheses, including nine fibrocartilaginous and four fibrous ones (Table 9). Twelve of them were repeatedly mentioned in the "horse riding syndrome" literature, and most of those were frequently used and described in the literature on EC. The origin site of the straight head of the rectus femoris at the anterior inferior iliac spine (COX E1) was also included considering the function played by this muscle (hip flexion, knee extension), and the fact that there is no other muscle attached to this site, allowing to discuss more precisely the relation between the EC and the movements allowed by the muscle related to the enthesis. In addition, it is a fibrocartilaginous enthesis [START_REF] Dragoni | Rectus femoris tendinopathy[END_REF]. The changes at the insertion site of the obturator externus and obturator internus, in the trochanteric fossa, are rarely scored as EC (Belcastro et al., 2001;[START_REF] Lieverse | Lower limb activity in the Cis-Baikal: entheseal changes among middle Holocene Siberian foragers[END_REF], but more often as a morphological variant (or nonmetric trait), under the appellation "spicules" or "exostosis" in the trochanteric fossa [START_REF] Finnegan | Non-metric variation of the infracranial skeleton[END_REF]. This insertion site is also considered as a fibrocartilaginous enthesis [START_REF] Tichnell | Invisible Horsewomen: Horse Riding and Social Dynamics on the Steppe[END_REF][START_REF] Lieverse | Lower limb activity in the Cis-Baikal: entheseal changes among middle Holocene Siberian foragers[END_REF]. Finally, the adductor tubercle, insertion site of the adductor magnus, is also rarely scored as a common enthesis, but it was included here considering that is it the attachment site of a single determinant muscle for horse riding. It is considered as a fibrous enthesis [START_REF] Tichnell | Invisible Horsewomen: Horse Riding and Social Dynamics on the Steppe[END_REF][START_REF] Djukic | Bone microarchitecture at muscle attachment sites: The relationship between macroscopic scores of entheses and their cortical and trabecular microstructural design[END_REF]. The origin sites of the semimembranosus, the semitendinosus, and the long head of the biceps femoris were combined and scored as one enthesis, as well as the middle medial and lateral lips of the linea aspera on the femur, where are attached multiple muscles. These entheses may indeed be difficult to distinguish precisely, and this distinction is rarely mentioned in the literature on horse riding. Their combination allows improving the reliability of the scoring and the possibility to make comparisons.

Some notable examples of the EC that were scored are presented in Figure 12 and

III.A.2. Joint changes

We discussed how joint changes can be used as activity-related skeletal changes and their limitations (see Chapter 1, I.B and I.C). Various methods using a multiple-grade scale have been used for scoring joint changes [START_REF] Crubézy | Interactions entre facteurs bio-culturels, pathologie et caractères discrets. Exemple d'une population mediévale : Canac (Aveyron)[END_REF]Buikstra & Ubelaker, 1994;[START_REF] Rogers | A field guide to joint disease in archaeology[END_REF]. However, bone preservation often represents a limit in archaeological materials, leading to very limited sample sizes for each grade. Furthermore, the use of a multiple-grade scale greatly depends on the experience of the observer and can lead to low repeatability of the scoring method. In this regard, degrees of severity are often clustered into two categories: absence (or barely discernible presence) of changes, and presence of (obvious) changes, notably when joint surfaces are combined into major articulations (e.g., Alves [START_REF] Alves Cardoso | A portrait of gender in two 19th and 20th century Portuguese populations: a palaeopathological perspective[END_REF][START_REF] Ponce | A comparative study of activity-related skeletal changes in 3rd-2nd millennium BC coastal fishers and 1st millenium AD inland agriculturists in Chile, South America[END_REF][START_REF] Zampetti | Variation of skeletal degenerative joint disease features in an identified Italian modern skeletal collection[END_REF]. In our study, a score of 1 (present) was given to a joint when there was clearly discernible osteophyte formation on the surface or the rim of an articular surface, joint contour deformation, eburnation, or loss of morphology of the joint. The presence of porosity alone was not enough to receive a score of 1, as it is sometimes difficult to differentiate from taphonomic processes and its cause is not fully understood [START_REF] Rothschild | Porosity: A curiosity without diagnostic significance[END_REF][START_REF] Groves | Spears or ploughshares: Multiple indicators of activity related stress and social status in four Early Medieval population from the North East of England[END_REF][START_REF] Schrader | Activity, Diet and Social Practice. Addressing Everyday Life in Human Skeletal Remains[END_REF]. We must stress that the aim was not here to propose a reliable diagnostic of osteoarthritis as a condition, but, rather in a descriptive approach, to evaluate differences in the presence of bone changes at the joints between groups, to determine if the practice of horse riding could have an influence on their development.

The articular surfaces composing each joint from the acetabulum to the trochlea of the talus (except the proximal tibiofibular joint) were systematically and precisely scored (Figure 14 and 15). The articular surfaces were then combined into the major joints of the lower limb to identify which may be affected more by changes related to the practice of horse riding (Table 10). The patellofemoral and tibiofemoral joints, both components of the knee, were analyzed independently, as they involve different articular surfaces. In addition, joint changes at the patella were specifically observed in riding populations and assumed to be related to the use of stirrups, also used by the populations from the Hungarian Conquest period [START_REF] Baillif-Ducros | Stirrups and archaeological populations: Bioanthropological considerations for determining their use based on the skeletons of two Steppe riders[END_REF][START_REF] Baillif-Ducros | La pratique de la monte à cheval au haut Moyen Âge (fin Ve-VIIe siècle) dans le nord-est de la Gaule. État des connaissances archéologiques[END_REF]. Osteophytes of the fovea capitis of the femur were also mentioned in the anthropological literature on horse riding (see Chapter 1, II.D.1), even if it is rather considered that they affect high-level athletes, in general, and not specifically horse riders (Auvinet, 1980a;[START_REF] Baillif-Ducros | La pratique de la monte à cheval au haut Moyen Âge (fin Ve-VIIe siècle) dans le nord-est de la Gaule. État des connaissances archéologiques[END_REF]. The presence of perifoveal osteophytes was investigated in our study, independently from the joint changes of the coxofemoral joint (Figure 16). The presence of perifoveal osteophytes only and no other changes at the femoral head was not considered for attributing a score 1 to the coxofemoral joint (Baillif-Ducros, 2018, following [START_REF] Demarais | La hanche du cavalier[END_REF].

Although vertebral joint changes (at the vertebral bodies and articular facets) were repeatedly mentioned in the anthropological literature on horse riding, we did not include them in the present study. Their use as activity-related markers has indeed been discussed, due notably to the structure and function of the spine and the strong correlation of vertebral joint changes with age and other factors [START_REF] Bridges | Vertebral arthritis and physical activities in the prehistoric Southeastern United States[END_REF][START_REF] Knüsel | Comparative degenerative joint disease of the vertebral column in the medieval monastic cemetery of the Gilbertine Priory of St[END_REF][START_REF] Weiss | Osteoarthritis revisited: A contemporary review of aetiology[END_REF][START_REF] Novak | Vertebral pathologies in two early modern period (16th-19th century) populations from Croatia[END_REF].

As for the analysis of entheseal changes, two series of analyses were performed: one with only young and mature adult individuals, and the other with individuals in all adult age categories (see III.C.2 below).

III.A.3. Morphological variants of the femur

Morphological variants, nonmetric or discrete traits, include various skeletal changes that are usually considered as nonpathological and can result from multiple internal and external causes. If these causes are not fully understood, it is often assumed that there is an underlying genetic component that plays an important part in the development of most variants. They are thus widely used in biological distance studies for analyzing population affinity. It is however acknowledged that sex, age, or activity can also be determining factors for these traits [START_REF] Berry | Factors affecting the incidence of non-metrical skeletal variants[END_REF][START_REF] Finnegan | Non-metric variation of the infracranial skeleton[END_REF][START_REF] Hauser | Epigenetic Variants of the Human Skull[END_REF][START_REF] Capasso | Atlas of Occupational Markers on Human Remains[END_REF][START_REF] Saunders | Nonmetric Trait Variation in the Skeleton: Abnormalities, Anomalies, and Atavisms[END_REF]Mann & Hunt, 2013).

As discussed previously, various morphological variants have been used and interpreted as horse riding-related skeletal changes (see Chapter 1, II.D.1). Most of them concern the femur, and the most frequently cited ones are the variations of the anterior aspect of the femoral headneck junction. These include different changes that are often not differentiated, leading to confusion regarding their presumed link with the practice of horse riding.

We selected six morphological variants, focusing especially on the proximal part of the femur, and including the most commonly cited variants in the literature that are assumed to be related to horse riding (Table 11). The aim was to evaluate the reliability of these indicators. We also included, in an exploratory approach, the posterior cervical imprint and the hypotrochanteric fossa, as they are well-defined traits that could appear to be interesting considering their location. The distinction between Poirier's facet, anteroiliac plaque, and Allen's fossa relied on the redefinition by [START_REF] Radi | Variation of the anterior aspect of the femoral head-neck junction in a modern human identified skeletal collection[END_REF]. All selected morphological variants were scored as a dichotomous variable (presence/absence) following these definitions:

Poirier's facet: lateral expansion of the articular surface of the femoral head articular surface onto the anterior aspect of the femoral neck, smooth, on the same plane and in continuity with the articular surface of the head [START_REF] Kostick | Facets and imprints on the upper and lower extremities of femora from a Western Nigerian population[END_REF][START_REF] Finnegan | Non-metric variation of the infracranial skeleton[END_REF][START_REF] Capasso | Atlas of Occupational Markers on Human Remains[END_REF][START_REF] Villotte | Some remarks about femoroacetabular impingement and osseous non-metric variations of the proximal femur[END_REF]Mann & Hunt, 2013;[START_REF] Radi | Variation of the anterior aspect of the femoral head-neck junction in a modern human identified skeletal collection[END_REF] (Figure 17a).

Anteroiliac plaque: imprint located on the anterior margin of the femoral neck close to the head. It is a bony overgrowth that may be on the same plane as the femoral head, lower than the femoral neck plane, or on an intermediate level, and may be delimitated by a bony rim.

Unlike the articular surface of the head or Poirier's facet, it has an entirely rough surface. It can be present in addition to Poirier's facet and Allen's fossa [START_REF] Finnegan | Non-metric variation of the infracranial skeleton[END_REF][START_REF] Villotte | Some remarks about femoroacetabular impingement and osseous non-metric variations of the proximal femur[END_REF]Mann & Hunt, 2013;[START_REF] Radi | Variation of the anterior aspect of the femoral head-neck junction in a modern human identified skeletal collection[END_REF] (Figure 17b).

Allen's fossa: circumscribed area on the anterior portion of the femoral neck, close to the border of the head, characterized by a cortical erosion with exposition of the trabecular bone [START_REF] Kostick | Facets and imprints on the upper and lower extremities of femora from a Western Nigerian population[END_REF][START_REF] Finnegan | Non-metric variation of the infracranial skeleton[END_REF][START_REF] Capasso | Atlas of Occupational Markers on Human Remains[END_REF][START_REF] Villotte | Some remarks about femoroacetabular impingement and osseous non-metric variations of the proximal femur[END_REF]Mann & Hunt, 2013;[START_REF] Radi | Variation of the anterior aspect of the femoral head-neck junction in a modern human identified skeletal collection[END_REF]. The presence of an area with clustered pores of 1mm or more of diameter on the cortical surface, categorized as a score 1 cribra by [START_REF] Radi | Variation of the anterior aspect of the femoral head-neck junction in a modern human identified skeletal collection[END_REF], was also included in the scoring of this variant for this study as this feature was probably also referred to as Allen's fossa (or cervical fossa) in previous studies, without distinction (Figure 17c).

Posterior cervical imprint: facet located on the posterior aspect of the neck that may be laterally delimitated by a tubercle [START_REF] Kostick | Facets and imprints on the upper and lower extremities of femora from a Western Nigerian population[END_REF][START_REF] Capasso | Atlas of Occupational Markers on Human Remains[END_REF]. [START_REF] Kostick | Facets and imprints on the upper and lower extremities of femora from a Western Nigerian population[END_REF] defines it as "a facet resembling Poirier's". The figure provided by the author to illustrate this imprint shows, however, a circumscribed area for which appearance looks closer to the anteroiliac plaque, being on a lower plane as the articular surface of the head. In that regard, we recorded as a posterior cervical imprint any facet, continuous or discontinuous with the head surface, smooth or rough, delimitated or not by a rim, as long as it was observed on the posterior femoral neck and close to the head (Figure 17d).

Third trochanter: rounded or oval tubercle found at the superior end of the gluteal tuberosity (line, crest, or ridge). It develops instead of, or above it, and often resembles the lesser trochanter in form [START_REF] Hrdlička | The gluteal ridge and gluteal tuberosities (3rd trochanters)[END_REF][START_REF] Finnegan | Non-metric variation of the infracranial skeleton[END_REF][START_REF] Lozanoff | Third trochanter incidence and metric trait covariation in the human femur[END_REF][START_REF] Mann | Relationships between lower limb cross-sectional geometry and mobility: The case of a Neolithic sample from Italy[END_REF] (Figure 17e).

Hypotrochanteric fossa: fossa located in the superior posterior part of the femoral diaphysis between the gluteal tuberosity and the lateral margin. It can be associated with the third trochanter [START_REF] Hrdlička | The hypotrochanteric fossa of the femur (with 14 plates)[END_REF][START_REF] Finnegan | Non-metric variation of the infracranial skeleton[END_REF][START_REF] Mann | Relationships between lower limb cross-sectional geometry and mobility: The case of a Neolithic sample from Italy[END_REF] (Figure 17f).

III.A.4. Vertebral changes

III.A.4.a. Schmorl's nodes

Schmorl's nodes (SN) are vertical herniations of intervertebral disc tissue (nucleus pulposus) that appear in bone in the form of a well-defined and smooth-walled lesion on the superior or inferior surface of the vertebral body. They are frequent in past and modern populations, and especially in young people who practice a physical activity at a high level, with a predominance in males. Their etiology is still unclear, but trauma, long-term mechanical loading, and congenital weakening are among the most debated factors. In bioarchaeology, SN are often used as indicators of stress to discuss activities and behaviors in past populations [START_REF] Capasso | Atlas of Occupational Markers on Human Remains[END_REF][START_REF] Groves | Spears or ploughshares: Multiple indicators of activity related stress and social status in four Early Medieval population from the North East of England[END_REF][START_REF] Alves Cardoso | A portrait of gender in two 19th and 20th century Portuguese populations: a palaeopathological perspective[END_REF][START_REF] Faccia | Schmorl's nodes: clinical significance and implications for the bioarchaeological record[END_REF][START_REF] Üstündağ | Schmorl's nodes in a post-medieval skeletal sample from Klostermarienberg, Austria[END_REF][START_REF] Waldron | Palaeopathology[END_REF][START_REF] Novak | Vertebral pathologies in two early modern period (16th-19th century) populations from Croatia[END_REF]. They are among the most cited skeletal changes assumed to be related to the practice of horse riding (see Chapter 1, II.D.1).

SN were scored according to their severity, following the precise description proposed by [START_REF] Knüsel | Comparative degenerative joint disease of the vertebral column in the medieval monastic cemetery of the Gilbertine Priory of St[END_REF], and used by Üstündağ (2009) in their methodological study of SN (Table 12; Figure 18). As SN usually have a high prevalence in populations, this scoring procedure may be better suited to reveal differences between groups related to a different level of activity, and more specifically, to the practice of horse riding, compared to using a simple binary recording procedure. Less than 2mm deep covering an area equivalent to less than half the anteroposterior length of the vertebral body Large Schmorl's nodes (2) More than 2mm deep covering an area of more than half the anteroposterior length of the vertebral body SN were scored on each vertebra that could precisely be identified in the column. Both superior and inferior endplates were scored separately, and a vertebra was considered as affected if at least one of these surfaces showed the presence of a node. If SN were observable on both surfaces of a vertebra, the highest score was attributed to the whole vertebra. A vertebra was considered as observable if more than half of the surface of at least one endplate was observable.

We analyzed the results for each vertebra from the first thoracic to the first sacral vertebra taken separately in order to precisely identify which vertebrae were more affected by SN in each group. Vertebrae were also combined by segment, to be able to observe more differences depending on the general level of the lesions. The upper (from the first to the sixth thoracic vertebra) and lower thoracic levels (from the seventh to the twelfth vertebra) were distinguished and also combined together to be compared with the lumbar level (from the first lumbar to the first sacral vertebra).

We must acknowledge, for the scoring of SN on vertebrae, the major contribution of our colleague from the Department of Biological Anthropology of the University of Szeged, Balázs Tihanyi, whose doctoral research relied on the same materials. Considering the simplicity and precision of the scoring method used for recording SN, and the fact that we trained together for the scoring of all skeletal changes, an interobserver agreement evaluation was not deemed necessary.

III.A.4.b. Spondylolysis

Spondylolysis is a defect in the neural arches at the pars interarticularis of the vertebrae.

It results in the separation between the anterior part (body, pedicles, transverse processes, superior articular facets) and the posterior part of the vertebra (inferior articular facets, laminae, spinous process). It can occur bilaterally or unilaterally. Its prevalence is higher in athletic populations, and it seems to appear in childhood or early adulthood, and more frequently in males. Spondylolysis does not seem to increase with aging. Its etiology is debated, and genetic factors and stress fracture are among the most cited possible causes. This trait is often used in bioarchaeology for investigating stress level in past populations [START_REF] Merbs | Patterns of Activity-induced Pathology in a Canadian Inuit Population[END_REF][START_REF] Bridges | Spondylolysis and its relationship to degenerative joint disease in the prehistoric Southeastern United States[END_REF][START_REF] Merbs | Spondylolysis: its nature and anthropological significance[END_REF][START_REF] Capasso | Atlas of Occupational Markers on Human Remains[END_REF][START_REF] Fibiger | Prevalence rates of spondylolysis in British skeletal populations[END_REF][START_REF] Molnar | Tracing prehistoric activities: Musculoskeletal stress marker analysis of a stone-age population on the Island of Gotland in the Baltic sea[END_REF][START_REF] Waldron | Palaeopathology[END_REF][START_REF] Ponce | A comparative study of activity-related skeletal changes in 3rd-2nd millennium BC coastal fishers and 1st millenium AD inland agriculturists in Chile, South America[END_REF]. Spondylolysis was occasionally cited among the skeletal changes assumed to be related to the practice of horse riding (see Chapter 1, II.D.1).

Spondylolysis was scored as present or absent. When present, we also noted when it was unilateral or bilateral (Figure 19). Although spondylolysis is more commonly associated with the lumbar vertebrae, all vertebrae from the third cervical to the first sacral vertebra were examined. As for Schmorl's nodes, we acknowledge, for the scoring of spondylolysis, the valuable contribution of our colleague from the Department of Biological Anthropology of the University of Szeged, Balázs Tihanyi, whose doctoral research relied on the same materials.

III.A.5. Traumatic lesions

Traumatic lesions can be of particular interest in the study of past populations as they can result from conflicts or natural accidents, thus providing insights of the environment in which evolved the individuals or their activities and behaviors [START_REF] Pálfi | Traces des activités sur les squelettes des anciens Hongrois[END_REF][START_REF] Larsen | Bioarchaeology: Interpreting behavior from the human skeleton[END_REF][START_REF] Jurmain | Stories from the Skeleton[END_REF][START_REF] Buzon | Traumatic injuries and imperialism: The effects of Egyptian colonial strategies at Tombos in upper Nubia[END_REF][START_REF] Paine | Cranial trauma in iron age Samnite agriculturists, Alfedena, Italy: Implications for biocultural and economic stress[END_REF][START_REF] Tung | Trauma and violence in the Wari empire of the Peruvian Andes: Warfare, raids, and ritual fights[END_REF][START_REF] Henderson | Musculo-skeletal stress markers in bioarchaeology: indicators of activity levels or human variation? A re-analysis and interpretation[END_REF][START_REF] De La Cova | Patterns of trauma and violence in 19th-century-born African American and Euro-American females[END_REF]. Traumatic lesions at various locations on the skeleton have been described as being possibly related to the practice of horse riding, and especially the fall from a horse, while fractures are very common in modern horse riders [START_REF] Ki | Horse-riding accidents and injuries in historical records of Joseon Dynasty, Korea[END_REF] The presence of signs of fractures was systematically recorded. The results were analyzed according to grouped bones and anatomical regions as presented in Table 13. We included only fractures for which traces were macroscopically observable, with clearly discernible signs of the presence of a primary bone callus, bone deformation such as shortening or angulation, and loss of joint morphology (Figure 20). Microtraumatic lesions or cases of myositis ossificans, i.e., ossification of injured muscles, were not considered here. A case of surgical trepanation at the occipital bone in the Hungarian series was not included in this analysis. Traumas were recorded on both sides in the case of paired bones but the results were combined and asymmetry was not considered for this analysis. Groups of bones or regions were considered as observable when at least half of the elements composing them were observable. We acknowledge the fact that the scoring of traumatic lesions on the upper part of the skeleton was performed by our colleague from the Department of Biological Anthropology of the University of Szeged, Balázs Tihanyi, whose doctoral research relied on the same materials.

They were included in this study with the fractures of the lower limbs considering that anthropological literature and sports medicine, especially, refer to acute traumas at the upper part of the body as being a very common consequence of horse riding.

Osteometric analyses

III.B.1. The index of ovalization of the acetabulum

The practice of horse riding is suspected of altering the shape of the acetabulum due to the pressure of the femoral head on the acetabulum related to the position of the rider [START_REF] Baillif-Ducros | Approche méthodologique pour distinguer un ensemble lésionnel fiable de la pratique cavalière. Exemple du squelette de la tombe 11 du site de « La Tuilerie » à Saint-Dizier (Haute-Marne), VIe siècle[END_REF]. Changes that are mentioned in the literature are described as an ovalization of the acetabulum or an expansion/elongation of the rim, which can be anterior-superior or superior (e.g., [START_REF] Miller | The Effect of Horseback Riding on the Omaha and Ponca: Paleopathological Indications of European Contact[END_REF][START_REF] Pálfi | Traces des activités sur les squelettes des anciens Hongrois[END_REF][START_REF] Courtaud | Osteomorphological features of nomadic riders: Some examples from Iron Age populations located in southwestern Siberia[END_REF][START_REF] Erickson | Fourier analysis of acetabular shape in Native American Arikara populations before and after acquisition of horses[END_REF][START_REF] Garofalo | The osteologic markers of horseback riding: An examination of two medieval English populations[END_REF][START_REF] Üstündağ | A possible case of Scheuermann's disease from Akarçay Höyük, Birecik (Şanlıurfa, Turkey)[END_REF][START_REF] Baillif-Ducros | Approche méthodologique pour distinguer un ensemble lésionnel fiable de la pratique cavalière. Exemple du squelette de la tombe 11 du site de « La Tuilerie » à Saint-Dizier (Haute-Marne), VIe siècle[END_REF][START_REF] Eng | Morphometric analysis of acetabular rim shape among ancient Mongolian pastoralists[END_REF][START_REF] Baillif-Ducros | Stirrups and archaeological populations: Bioanthropological considerations for determining their use based on the skeletons of two Steppe riders[END_REF][START_REF] Fornaciari | A great enigma of the Italian Renaissance: paleopathological study on the death of Giovanni dalle Bande Nere (1498-1526) and historical relevance of a leg amputation[END_REF][START_REF] Ciurletti | Analisi biomeccanica del femore e del coxale per comprendere l'economia di sussistenza e il comportamento occupazionale legato all'uso del cavallo nella populazione della necropoli di Olmo di Nogara (Bronzo medio, Verona)[END_REF][START_REF] Larentis | San Martino di Lundo (Trento) Grave 1. Case study of an individual introducing possibilities markers of horse riding[END_REF][START_REF] Baillif-Ducros | La pratique de la monte à cheval au haut Moyen Âge (fin Ve-VIIe siècle) dans le nord-est de la Gaule. État des connaissances archéologiques[END_REF]. The results of a visual examination greatly depend on the experience of the observer, thereby limiting the reliability and reproducibility of the observations. Therefore, different methodologies have been experimented to identify precise, reliable, and repeatable criteria to describe the acetabular shape changes. Although the Fourier analysis used by [START_REF] Erickson | Fourier analysis of acetabular shape in Native American Arikara populations before and after acquisition of horses[END_REF] on acetabula from two Native American Arikara populations seems particularly relevant to capture the changes of the shape of the entire acetabular rim, several portions of the acetabular rim are frequently not preserved in ancient materials. Instead, we used direct measurements of the acetabulum to calculate a vertical/horizontal diameter index and analyze the shape of the acetabulum [START_REF] Baillif-Ducros | Approche méthodologique pour distinguer un ensemble lésionnel fiable de la pratique cavalière. Exemple du squelette de la tombe 11 du site de « La Tuilerie » à Saint-Dizier (Haute-Marne), VIe siècle[END_REF]Berthon et al., 2016b;[START_REF] Sarry | La sépulture multiple laténienne du site de Gondole (Le Cendre, Puy-de-Dôme)[END_REF][START_REF] Baillif-Ducros | La pratique de la monte à cheval au haut Moyen Âge (fin Ve-VIIe siècle) dans le nord-est de la Gaule. État des connaissances archéologiques[END_REF][START_REF] Berthon | Horse riding and the shape of the acetabulum: Insights from the bioarchaeological analysis of early Hungarian mounted archers (10th century)[END_REF]. The vertical and horizontal diameters are relevant to assess the anterior-superior rim expansion previously described [START_REF] Erickson | Fourier analysis of acetabular shape in Native American Arikara populations before and after acquisition of horses[END_REF][START_REF] Baillif-Ducros | Approche méthodologique pour distinguer un ensemble lésionnel fiable de la pratique cavalière. Exemple du squelette de la tombe 11 du site de « La Tuilerie » à Saint-Dizier (Haute-Marne), VIe siècle[END_REF].

The metrics are well-defined measurements that can be easily taken: VEAC (M22) corresponds to the maximum vertical diameter of the acetabulum, measured as a prolongation of the longitudinal axis of the ischium, and HOAC (M22) is the maximum horizontal diameter, measured perpendicularly to VEAC [START_REF] Baillif-Ducros | Approche méthodologique pour distinguer un ensemble lésionnel fiable de la pratique cavalière. Exemple du squelette de la tombe 11 du site de « La Tuilerie » à Saint-Dizier (Haute-Marne), VIe siècle[END_REF][START_REF] Bräuer | Anthropologie, Handbuch der vergleichenden Biologie des Menschen[END_REF][START_REF] Bruzek | Validation and reliability of the sex estimation of the human os coxae using freely available DSP2 software for bioarchaeology and forensic anthropology[END_REF][START_REF] Murail | DSP: a tool for probabilistic sex diagnosis using worldwide variability in hip-bone measurements[END_REF]. The measurements are neither external nor internal but taken precisely on the rim of the acetabulum (Figure 21a). They were used to calculate a vertical/horizontal diameter index (VEAC/HOAC) that allows comparing the acetabular shape between individuals, groups, and studies. This index of ovalization of the acetabulum (IOA)

indicates a vertical ovalization when it is higher than 1 (VEAC > HOAC), whereas an IOA close to 1 corresponds to circular acetabula, and an IOA inferior to 1 indicates acetabula wider than their height (HOAC > VEAC; Figure 21b,c). The metrics were recorded with a digital sliding caliper with a precision of 0.1 mm. Both left and right acetabula were measured to address asymmetry questions. We excluded suspected cases of hip dysplasia, subluxation or dislocation, and acetabula showing strong osteophytosis at the rim.

Considering the particular interest of this index for the analysis of horse riding-related skeletal changes, and the fact that the measurements of the acetabula, although well defined, are not very commonly used in anthropological studies, we performed an interobserver and intraobserver agreement evaluation to assure the reproducibility of the measurements. The measurements were taken by one observer (A) in the Hungarian archaeological series, without knowledge of the presence or absence of horse riding deposit in the graves of the individuals.

Additionally, a set of measurements was taken by a second observer (B), independently.

Observer A had more practical experience than Observer B in metrics of the coxal bone, but both observers are experienced in osteometry. The definitions and techniques of measurements were clarified before the test. Observer A also performed a second round of measurements (A2), with an interval of several months, to assess the intraobserver agreement. Observer B's measurements were compared with the A2 set. Thirty coxae from 15 individuals were measured for comparing the vertical and the horizontal diameters, respectively. The individuals were selected randomly among the adults, provided that the acetabular rim was well preserved. The concordance between the series of measurements was evaluated using the concordance correlation coefficient that allows quantifying the agreement between two measures of the same variable (Lin, 1989). Values are ranged between -1 and 1, with ±1 denoting a perfect concordance or discordance and 0 denoting an absence of correlation.

III.B.2. Other indices of shape and robusticity

External dimensions of bones can, like cross-sectional geometry (CSG), contribute to identifying differences in activity patterns between and within populations (Buikstra & Ubelaker, 1994;[START_REF] Larsen | Bioarchaeology: Interpreting behavior from the human skeleton[END_REF]Knüsel, 2000b;[START_REF] Stock | Hunter-gatherer postcranial robusticity relative to patterns of mobility, climatic adaptation, and selection for tissue economy[END_REF][START_REF] Perréard Lopreno | Adaptation structurelle des os du membre supérieur et de la clavicule à l'activité : analyse de l'asymétrie des propriétés géométriques de sections transverses et de mesures linéaires dans une population identifiée[END_REF]Shaw & Stock, 2009b, 2009a;Niinimäki, 2012a). This relies on the ability of bones to adapt to mechanical loading (see Chapter 1, I.B). If CSG provides more detailed information regarding the architectural properties of long bones, external bone dimensions have also proved to be informative, reliable, and accurate when compared to CSG results [START_REF] Stock | Which measures of diaphyseal robusticity are robust? A comparison of external methods of quantifying the strength of long bone diaphyses to cross-sectional geometric properties[END_REF][START_REF] Ponce | A comparative study of activity-related skeletal changes in 3rd-2nd millennium BC coastal fishers and 1st millenium AD inland agriculturists in Chile, South America[END_REF]. Large databases on external bone dimensions also allow to record in a more complete way variations of the human skeleton, and this approach can furthermore be preferred for practical, time, and cost reasons [START_REF] Ponce | A comparative study of activity-related skeletal changes in 3rd-2nd millennium BC coastal fishers and 1st millenium AD inland agriculturists in Chile, South America[END_REF].

External measurements can be used to calculate various indices of shape and robusticity.

In humans, lower limbs are part of the locomotor system and are therefore more likely to reflect the effect of mobility, while upper limbs, used to perform manual activities, are more likely to provide information on specific activities and asymmetry [START_REF] Ponce | A comparative study of activity-related skeletal changes in 3rd-2nd millennium BC coastal fishers and 1st millenium AD inland agriculturists in Chile, South America[END_REF]. The index of ovalization of the acetabulum is a particular case: it was indeed specifically selected for being a potential reliable indicator of the practice of horse riding and because the changes of the shape of the acetabulum have been repeatedly mentioned in the anthropological literature on horse riding (see III.B.1 above). In an exploratory approach, we selected various other indices calculated from direct measurements on the lower limb bones. Unlike the index of ovalization of the acetabulum, suspected to be influenced specifically by the practice of horse riding, these other indices are rather general descriptors of the overall shape and robusticity of the main bones of the lower limb, and we thus assume that they can allow identifying differences in the level of activity and mobility between groups. Specifically, the comparison between both Hungarian archaeological groups, with (RD) and without riding deposit (NRD), is of particular interest as they are considered as coming from the same population. In that regard, possible differences between these two groups are less likely to be related to interpopulation variability and, more likely, to external factors. The distinction between both groups relying only on the presence or absence of horse-related deposit (riding equipment and horse bones) in the graves, differences in the practice of horse riding would represent a logical explanation for possible variations of those indices observed between those groups.

A selection of measurements was taken on the femur, patella, tibia, fibula, talus, and calcaneus. These metrics mostly include the maximum or physiological length, anteroposterior and mediolateral diameters at midshaft, or the minimum circumference of the diaphysis in case of long bones, as well as the maximum or articular length, breadth, and height, in the case of the tarsal bones. The measurements are all well defined by R. Martin (in the reedition by G. [START_REF] Bräuer | Anthropologie, Handbuch der vergleichenden Biologie des Menschen[END_REF], and are commonly used in anthropology. In that respect, no inter-or intraobserver agreement evaluation was performed. The metrics were recorded using a digital sliding caliper with a precision of 0.1 mm, as well as an osteometric board, a spreading caliper, and a measuring tape, with a precision of 1 mm. Both left and right bones were measured.

The measurements were used to calculate the indices of shape and robusticity (Table 14).

The selected indices are also defined by Martin (in the reedition by [START_REF] Bräuer | Anthropologie, Handbuch der vergleichenden Biologie des Menschen[END_REF] and are used in anthropology to characterize individuals and populations (Janssens & Perrot, 2006-2007).

Unlike raw measurements, indices do not require to control for the size factor, and they easily allow comparisons between individuals or groups. We must stress that our intergroup comparisons relied only on the direct result of the index calculation, and not on the classical categorization of bones shape traditionally used by anthropologists to describe populations.

Limiting bias

III.C.1. The influence of pathological conditions

For both qualitative and quantitative analyses, the data were excluded -considered as not observable -for the concerned bone or bone part in case of presence of possible or probable signs of a pathological condition. The data were, however, excluded for the whole lower limb from the concerned side or both sides in the most severe cases, which would have likely caused such discomfort for the individual that it could have altered lower limb movements. Even if this potential discomfort was only temporary and the pathology could have been well treated, there is a risk it resulted in the irregular development or the absence of development of some skeletal changes. When only one side presented signs of a severe condition, the data regarding the "healthy side" were not excluded (except in case of a strong asymmetry of values), even if we acknowledge the fact that irregular skeletal changes may also indirectly result from the pathological condition on the other side, due to a compensation mechanism for example. This decision was taken as a compromise for avoiding too little sample size in the case of the archaeological groups where bone preservation was already a limiting factor. Severe cases included conditions such as fractures of the femur or tibia, polytraumas, or osteomyelitis.

Probable cases of hip dysplasia also led to data exclusion on the concerned side or both sides (Figure 22). Suspected cases were verified with the measurements of the femoral neck-shaft angle, the tönnis angle, and the lateral center-edge angle (Serra-Tosio, 2011). However, such measurements are mainly adapted for radiographical examination; thus, cases that remained doubtful afterward were also excluded from the statistical analyses. For the analysis of entheseal changes, in particular, possible cases of diffuse idiopathic skeletal hyperostosis (DISH, or Forestier's disease) were excluded from the data set, as this metabolic disorder is particularly characterized by the calcification and ossification of soft tissues, including ligaments and tendons [START_REF] Resnick | Radiographic and pathologic features of spinal involvement in diffuse idiopathic skeletal hyperostosis (DISH)[END_REF][START_REF] Waldron | Palaeopathology[END_REF][START_REF] Holgate | Diffuse idiopathic skeletal hyperostosis: Diagnostic, clinical, and paleopathological considerations[END_REF]. The main diagnostic criteria considered to identify a probable or possible DISH were: the ossification of the right side anterior longitudinal ligament on the vertebrae, with a "candle wax" appearance, on at least 3-4 contiguous vertebrae; normal intervertebral disc spaces and apophyseal joints; absence of sacroiliac joint changes; and symmetric entheseal changes at locations such as the ulnar olecranon, superior patella, posterior calcaneus, or the iliac crest of the coxal bone [START_REF] Resnick | Radiographic and pathologic features of spinal involvement in diffuse idiopathic skeletal hyperostosis (DISH)[END_REF][START_REF] Rogers | DISH and the monastic way of life[END_REF][START_REF] Paja | Diffuse idiopathic skeletal hyperostosis -appearance and diagnostics in Hungarian osteoarcheological materials[END_REF][START_REF] Paja | Joint fusions in paleopathology: Diagnosis and epidemiology[END_REF][START_REF] Faccia | Diffuse idiopathic skeletal hyperostosis (DISH) in a middle Holocene forager from Lake Baikal, Russia: Potential causes and the effect on quality of life[END_REF]. Based on these criteria, three individuals from the comparison group from Lisbon (LIS) were excluded from the analysis of entheseal changes (Figure 23). Suspicious cases from the Hungarian series of Sárrétudvari-Hízóföld did not meet these criteria, and the observed changes were attributed to degenerative joint disease instead.

Similarly, the individual SH182 from Sárrétudvari-Hízóföld was excluded from the analysis of entheseal and joint changes because of signs of a probable inflammatory polyarthropathy [START_REF] Resnick | Diagnosis of Bone and Joint Disorders (4th Edition)[END_REF]. The skeleton displayed in fact generalized, bilateral and symmetric erosive alterations of the joints (intervertebral discs and apophyseal joints, acromioclavicular and sternoclavicular joints, sacroiliac joint, acetabulum, as well as carpal, metacarpal, tarsal, and metatarsal bones, hand and foot phalanges, etc.), with ankylosis of several vertebrae and phalanges, and entheseal changes at multiple sites.

III.C.2. The influence of age

Although it was demonstrated that the influence of activity on entheseal and joint changes is not straightforward, it is the conclusion of a majority of studies that their development is closely related to age (see Chapter 1, I.C). The presence of older adults in a sample

for analyzing those changes as potential activity-related markers represents, therefore, a bias, and the analysis of those changes should thus include only young and mature adults to limit the influence of age on the results.

The number of entheses and joints that could be observed was dependent on bone preservation, which was a limiting factor in the archaeological materials, especially. The strict methodological criteria that we used (see III.C.1 above) also narrowed down the sample sizes, and the age estimation let several individuals uncategorized (see I.B.3 above). In the end, the number of possible observations was particularly limited, especially if we focused only on the young and mature adults, as recommended.

In order to be able to conduct reliable statistical analyses and identify differences between groups, we performed two series of comparisons: one with only the young and mature adults, and another one, of a less limited size, including individuals in all adult age categories, i.e., young, mature, and old adults as well as adults of indeterminate age. Even if the development of entheseal and joint changes is closely related to age, the presence of old adults in each of the three groups should allow making intergroup comparisons. In details, on a total of 17 individuals in the Hungarian group with riding deposit (RD), six were estimated to be either mature or old adults, and four were indeterminate (Table 6); thus there could be a maximum of 10 old adults in this group (59%). Among the 50 individuals from the Hungarian group without riding deposit (NRD), 13 were considered as either mature or old adults, two were old adults, and five were indeterminate (Table 6); thus, there could be a maximum of 20 old adults in this group (40%). In comparison, based on the documentation, there were 15 individuals aged 50 or more in the group from the Lisbon collection (LIS) on a total of 47 (32%). However, the age estimation performed using the same method as for the archaeological groups (see II.C.2 above) led to categorize 33 individuals as either mature or old adults, or indeterminate (Table 7), which means 70% of possible old adults instead of the known 32%. It is therefore very unlikely that all of the individuals who were not precisely categorized as young and mature adults in the archaeological groups were actually old adults, and the real proportion of old individuals in the RD and NRD groups is probably less than the maximum estimations mentioned above, like in the case of the LIS group. Thus, we can reasonably consider that the proportion of old adults in the archaeological samples must not be disproportionate compared to the known old adults in the LIS group (32%), and, therefore, that the influence of age on the results should concern the three groups in a similar way, allowing for comparisons. Another argument for performing in a complementary way the analysis on individuals in all age categories is that older adults had more time to develop activity-related skeletal changes than those who died younger. In any case, we acknowledged the possible influence of age in the analyses including adults in all age categories. The results of these analyses were used to bring complementary results for comparison with the results obtained with young and mature adult individuals and will be discussed with caution.

As for the entheseal and joint changes, age can also represent a bias factor in the analysis of external bone measurements (and cross-sectional geometry) due to bone loss, which increases with age under the influence of multiple factors, including mechanical ones [START_REF] Frost | On changing views about age-related bone loss[END_REF][START_REF] Kirchengast | Bone loss and physical activity -A bio anthropological perspective[END_REF]. Age-related bone loss is however less in weight-bearing bones, such as the femur and tibia, in particular, compared to other bones, as they receive larger loads and larger muscle forces due to locomotion [START_REF] Peck | Intraskeletal variability in bone mass[END_REF]. In that regard, and in order to perform reliable statistical analyses with satisfactory sample sizes, we included individuals in all adult age categories in the analyses of indices of shape and robusticity of the lower limb bones.

Finally, concerning Schmorl's nodes, a methodological study revealed that they seem to occur more in young individuals and that their frequency does not increase with age. In addition, there was no association observed between Schmorl's nodes and degenerative vertebral joint diseases (Üstündağ, 2009). As Schmorl's nodes appear not to be related to the process of aging, their analysis also included individuals in all adult age categories in our study. In the same way,

we also used all individuals in our samples for the analysis of the morphological variants of the femur, spondylolysis, and traumatic lesions.

III.C.3. Other aspects

The protocol for the analysis of the activity-related skeletal changes was elaborated specifically for this study and it includes multiple types of skeletal changes for which scoring required practical training. For most of them, both qualitative and quantitative data, we felt a progression in our way of scoring over time, which was very likely related to the experience acquired after analyzing several dozens of skeletons. In order to limit the risk of having important differences between the first analyzed skeletons and the ones that were examined later with a "trained eye", the skeletons that were studied during the first weeks were reexamined again and all data were rescored. We used the second set of data for these skeletons in all analyses.

Furthermore, we must emphasize that the recording of all data from the different types of analyses was performed without knowledge of the presence or absence of horse-related deposit associated with the individuals in the graves, in the case of the Hungarian series.

Statistical analyses

III.D.1. General considerations

Our bioarchaeological analysis consists in identifying possible differences between the three groups selected in the sample: the Hungarian archaeological groups with (RD) and without riding deposit (NRD) and the comparison group from the documented collection of Lisbon (LIS). As a first step, we compared the three groups together. When a significant difference was observed, we had to perform pairwise comparisons to identify between which groups was found this significant difference. In our case, three pairs of groups were tested: RD versus NRD, RD versus LIS, and NRD versus LIS. We, therefore, had to take into account the multiple comparison problem.

In hypothesis testing, the significance level that is selected (α = .05, in most of the cases) corresponds to the accepted risk of falsely concluding that a difference that is observed is a reality while there is, in fact, no difference. When multiplying comparisons, we increase the risk of obtaining false-positive results, i.e., of falsely rejecting the null hypothesis in one of the tests. To address this problem, we must either lower the significance level α or correct the p values obtained from the multiple comparisons. We used the Holm-Bonferroni correction method, which sequentially increases the p values in order to decrease the risk of error: the smallest obtained p value is multiplied by the number of comparisons (N), the second smallest one is multiplied by N-1, the next one by N-2, etc. The application of a correction method results in adjusted p values. See [START_REF] Nikita | Osteoarchaeology. A guide to the macroscopic study of human skeletal remains[END_REF] for further details regarding the multiple comparison problem and the application of the Holm-Bonferroni method.

The sample sizes are not large: 17 individuals in the RD group, 50 in the NRD group, and 47 in the LIS group. The strict methodological criteria that we applied led to the exclusion of data concerning several of these individuals, depending on the type of analysis. Bone preservation was also a limiting factor in the archaeological groups, in particular.

Furthermore, when attempting to include only the young and mature adult individuals for the analysis of entheseal and joint changes, observations were made on a lower number of individuals. For these reasons, the conditions to perform parametric tests were frequently not met. In order to have homogenous results, we used non-parametric tests only, in all analyses.

The analyses were performed using SPSS Statistics 25. For all statistical tests, the set significance level was α = .05. We used exact p values, which provide a reliable result, regardless of the size or distribution of the data, whenever it was possible. When exact p values could not be computed, we applied the Monte Carlo method, a repeated sampling method that provides an unbiased estimate of the exact p value. Where applicable, two-tailed tests were systematically used.

III.D.2. Qualitative analyses

For the analysis of entheseal changes, joint changes, morphological variants, vertebral changes, and traumatic lesions, scoring each feature as "absent", "present" (small and large in the case of Schmorl's nodes), or "not observable" (usually when more than half of the element surface was altered or missing), allowed to calculate true prevalence rates: n/N, with n, the number of affected elements, and N, the number of observable elements for each analysis. In addition, we calculated the ratio of individuals affected by a condition (or presenting a feature), divided by the number of individuals who had enough observable elements for each type of analysis. Individuals were considered observable if half or more of the bone elements that were scored for each analysis were present.

The Fisher's exact test was used for comparison between the three groups, as well as for pairwise comparisons when a significant difference was noted. In that case, the obtained p values were corrected following the Holm-Bonferroni method (see III.D.1 above). The intergroup comparisons were performed using data from both sides, combined and taken independently. For the analysis of entheseal changes, joint changes, and morphological variants, bilateral asymmetry was also assessed, using paired bones or elements only. Bilateral asymmetry was calculated by subtracting the left side score from the right side for each individual (i.e., right score minus left score). This could result in three possible outcomes: "0" (equal scores, either for absence or presence on both sides), "1" (presence on the right side and absence on the left side), and "-1" (presence on the left side and absence on the right side).

Frequencies of each outcome were calculated per feature and per group. The pattern of bilateral asymmetry was also compared between groups using Fisher's exact test.

III.D.3. Quantitative analyses

Descriptive statistics (minimum, maximum, mean, standard deviation) were calculated for each index, on both sides. Considering its particular interest for horse riding, boxplots were constructed to visually represent the distribution of the index of ovalization of the acetabulum (IOA) in each group. For all indices, including the IOA, the non-parametric Kruskal-Wallis H test was used to assess differences between the three groups. When a statistically significant difference was found, we used the non-parametric Mann-Whitney U test to perform pairwise comparisons between the groups. In that case, the obtained p values were corrected following the Holm-Bonferroni method (see III.D.1). Those tests were applied to the indices of both sides, combined and taken independently. We also used the non-parametric Wilcoxon signed-rank test, applied on the paired indices in each group, to evaluate the bilateral asymmetry. The difference between both sides' indices was also calculated (right minus left index value), and the resulting values were compared between the groups using the Mann-Whitney U test to evaluate differences in the pattern of asymmetry.

CHAPTER 3. RESULTS

Macromorphoscopic analyses

The results of the sex diagnosis and the age estimation are presented in Chapter 2.

Results of the analysis of entheseal changes

I.A.1. Intergroup comparisons

I.A.1.

a. Young and mature adult individuals

A total of 1357 entheses could be observed in all young and mature adults, and 196 (14%)

were affected by changes. There was no difference between sides. There were more entheseal changes observed in the RD and NRD groups than in the LIS group (14%, 19%, and 11%, respectively, when left and right were combined; Table 15). The difference between the three groups was statistically significant, and pairwise comparisons revealed that this significant difference concerned the NRD and LIS group, in particular (p adjusted < .001). Those EC concerned a total of 45 young and mature adult individuals (75%) among the entire sample of 60 who were considered as observable (i.e., when at least half of the entheses were observable on each side). There was no significant difference between sides. A higher proportion of individuals was affected by at least one EC in the RD (86%) and NRD (84%) groups compared to the LIS group (64%; Table 16). This difference was not statistically significant (p = .211), nor was it when individuals were considered separately depending on if they were affected on their left or right side (p = .053 and p = .141, respectively). The frequencies of EC observed in each group and the results of the statistical comparisons between groups are shown in Table 17 and Figure 24.

The number of observations for each enthesis was rather limited due to the small sample size of YMA individuals and bone preservation in the archaeological materials and the RD group, in particular. The EC that were the most frequently observed in the entire sample concerned the calcaneal tuberosity (CAL E1, 39%), while the least frequently observed EC were those of the anterior surface of the greater trochanter of the femur (FEM E1, 3%). There was no significant difference between sides, even if 8 out of 13 entheses were slightly more affected on the left side. The NRD group showed the highest frequencies for a majority of EC (10/13). There was a statistically significant difference between groups for 3 entheses: the adductor tubercle of the femur (FEM E7), the tibial tuberosity (TIB E1), and the calcaneal tuberosity (CAL E1). The pairwise comparisons with corrected p values did not reveal a significant difference between any groups for FEM E7, even if we observed that the largest difference was between the RD group (38%) and the LIS group (5%), in particular. Concerning TIB E1, it was significantly more affected in the LIS group than in the NRD group (p adjusted = .018). This enthesis was not affected at all in the NRD and RD groups. As for CAL E1, EC were significantly more frequent in the RD and NRD groups compared to the LIS group (p adjusted = .012 and p adjusted < .001, respectively). 9 for the entheses' codes; * indicates statistically significant differences between groups (see Table 17)

0% 10% 20% 30% 40% 50% 60% 70% 80% 90% COX E1 L COX E1 R COX E2 L COX E2 R FEM E1 L FEM E1 R FEM E2 L FEM E2 R FEM E3 L FEM E3 R FEM E4 L FEM E4 R FEM E5 L FEM E5 R FEM E6 L FEM E6 R FEM E7 L FEM E7 R PAT E1 L PAT E1 R TIB E1 L TIB E1 R TIB E2 L TIB E2 R CAL E1 L CAL E1

I.A.1.b. Individuals in all adult age categories

When we included all the individuals from our sample, regardless of the estimated age categories in the archaeological series and the known age in the documented collection, we could observe a total of 2241 entheses, of which 579 (26%) were affected by changes. The frequencies of EC were higher than when focusing only on YMA, and there were still more EC observed in the RD and NRD groups than in the LIS group (28%, 34%, and 17%, respectively, when left and right were combined; Table 18). On both sides, the difference between the three groups was statistically significant, and pairwise comparisons revealed that this difference was significant between the NRD and LIS groups, in particular (p adjusted < .001), as well as between the RD and LIS groups (p adjusted < .001). There was also a significantly higher frequency of EC in the RD group compared to the NRD group, but only when data from both sides were combined (p adjusted = .034). Those EC concerned a total of 86 individuals (84%) among the entire sample of 102 who were considered as observable (i.e., when at least half of the entheses were observable on each side). A higher proportion of individuals were affected by at least one EC in the RD (94%) and NRD (91%) groups compared to the LIS group (73%; Table 19). This difference was statistically significant (p = .043). compared to the LIS group (60%) on the right side (p adjusted = .034). There was, however, no significant difference between sides.

The frequencies of EC observed in each group and the results of the statistical comparisons between groups are shown in Table 20 andFigure 25.

The number of observations for each enthesis was less limited than when selecting only YMA individuals. The EC that were the most frequently observed in the entire sample still concerned the calcaneal tuberosity (CAL E1, 54%), while the least frequently observed EC were also still those of the anterior surface of the greater trochanter of the femur (FEM E1, 10%). There was no significant difference between sides, even if 11 out of 13 entheses were slightly more affected on the left side. The NRD group showed the highest frequencies for a majority of EC (10/13). 9 for the entheses' codes; * indicates statistically significant differences between groups (see Table 20) There was a statistically significant difference between groups for 9 entheses: the anterior inferior iliac spine (COX E1), the ischial tuberosity (COX E2), the anterior surface of the greater trochanter (FEM E1), the trochanteric fossa (FEM E3), the linea aspera (FEM E6), the adductor tubercle (FEM E7), the tibial tuberosity (TIB E1), the soleal line (TIB E2), and the calcaneal tuberosity (CAL E1). Except for FEM E1 and TIB E1, pairwise comparisons showed for each enthesis a significant difference between the NRD group and the LIS group, in which EC were less frequent. For FEM E3, FEM E7, and FEM E7, there was also a significantly higher frequency of EC in the RD group compared to the LIS group. The largest differences observed concerned CAL E1 and were between the NRD (89%) and LIS (15%) groups on the left side (p adjusted < .001), and the RD (82%) and LIS (15%) groups on the right side. There was no significant difference between both Hungarian archaeological groups for any enthesis.

0% 10% 20% 30% 40% 50% 60% 70% 80% 90% 100% COX E1 L COX E1 R COX E2 L COX E2 R FEM E1 L FEM E1 R FEM E2 L FEM E2 R FEM E3 L FEM E3 R FEM E4 L FEM E4 R FEM E5 L FEM E5 R FEM E6 L FEM E6 R FEM E7 L FEM E7 R PAT E1 L PAT E1 R TIB E1 L TIB E1 R TIB E2 L TIB E2 R CAL E1 L CAL E1 R RD NRD LIS * * * * * * * * *

I.A.2. Bilateral asymmetry

Side dominance was analyzed using pairs of bones, which leads to smaller sample sizes.

Considering the limited amount of entheses that were already observable in the sample of young and mature adults, we used paired bones from individuals in all adult age categories for this analysis.

The results are shown in Table 21. In general, the left and right sides were equivalent, either in absence or presence of EC. The differences observed between sides tended to show more often a left-side dominance (presence on the left side and absence on the right side) for all groups, but these differences were light. The enthesis concerned the most by asymmetry was the trochanteric fossa (FEM E3), with 20% of unequal scores in the RD group, 27% in the NRD group, and 18% in the LIS group. Specifically, there was 20%, 15%, and 8% of right-side dominance in the RD, NRD, and LIS groups, respectively, while there was 0%, 12%, and 11% of left-side dominance. There was no statistically significant difference in the pattern of asymmetry between groups.

FEM E4 R = L 10 91% 26 93% 33 87% .824 R > L 0 0% 1 4% 1 3% L > R 1 9% 1 4% 4 11% N pairs 11 28 38 FEM E5 R = L 9 100% 33 97% 34 97% 1 R > L 0 0% 0 0% 1 3% L > R 0 0% 1 3% 0 0% N pairs 9 34 35 FEM E6 R = L 13 100% 37 97% 34 100% 1 R > L 0 0% 0 0% 0 0% L > R 0 0% 1 3% 0 0% N pairs 13 38 34 FEM E7 R = L 7 100% 25 100% 34 97% 1 R > L 0 0% 0 0% 0 0% L > R 0 0% 0 0% 1 3% N pairs 7 25 35 PAT E1 R = L 7 100% 14 88% 22 81% .094 R > L 0 0% 2 13% 0 0% L > R 0 0% 0 0% 5 19% N pairs 7 16 27
TIB E1 R = L 13 100% 29 88% 29 91% .775 R > L 0 0% 3 9% 3 9% L > R 0 0% 1 3% 0 0% N pairs 13 33 32
TIB E2 R = L 15 94% 34 85% 35 97% .301 R > L 0 0% 2 5% 1 3% L > R 1 6% 4 10% 0 0% N pairs 16 40 36 CAL E1 R = L 10 100% 30 94% 28 93% .892 R > L 0 0% 0 0% 1 3% L > R 0 0% 2 6%
1 3% N pairs 10 32 30 Fisher's exact test, two-sided; L, left side; R, right side; Asymmetry calculated as right side minus left side; R = L, equal scores; R > L, right score higher; L > R, left score higher

Results of the analysis of joint changes

I.B.1. Intergroup comparisons

I.B.1.a. Young and mature adult individuals

A total of 463 joints (as presented in Chapter 2, and apart from the fovea capitis case) could be observed in all young and mature adults, and 62 (13%) showed changes. There was no significant difference between sides. There were more joint changes observed in the LIS group than in the RD and the NRD groups (17%, 4%, and 11%, respectively, when left and right were combined; Table 22). The difference between the 3 groups was statistically significant (p = .044), even if pairwise comparisons with corrected p values did not reveal any significant difference between pairs of groups. Those changes concerned a total of 26 young and mature adult individuals (43%) among the entire sample of 60 who were considered as observable (i.e., when at least half of the joints were observable on each side). There was no significant difference between sides. A higher proportion of individuals showed changes at a minimum of one joint in the LIS group (52%) compared to the NRD (38%) and RD (29%) groups (Table 23). This difference was not statistically significant (p = .493). The frequencies of joint changes observed in each group and the results of the statistical comparisons between groups are shown in Table 24 and Figure 26. The number of observations for each joint was rather limited due to the small sample size of YMA individuals and bone preservation in the archaeological materials and in the RD group, in particular. The joint changes that were the most frequently observed in the entire sample concerned the acetabulofemoral joint (21%), while the least frequently observed joint changes were those of the talocrural joint (7%). There was no significant difference between sides. The LIS group showed the highest frequencies for all joints, except for the tibiofemoral joint where the frequency was higher for the NRD group on the left side (20% versus 13%). There was no statistically significant difference between groups.

Regarding the perifoveal osteophytes on the femoral head, in particular, the frequency was higher in the NRD group (38%) compared to the LIS (25%) and RD (22%) groups (Table 25).

There was no significant difference according to the side within each group, neither there was between groups. among the entire sample of 103 who were considered as observable (i.e., when at least half of the joints were observable on each side). There was also no significant difference between sides and groups (Table 27). The frequencies of joint changes observed in each group and the results of the statistical comparisons between groups are shown in Table 28 and Figure 27. The number of observations for each joint was less limited than on the YMA individuals.

The joint changes that were the most frequently observed in the entire sample still concerned the acetabulofemoral joint (38%), while the least frequently observed joint changes were those of the talocrural joint (11%). There was no significant difference between sides. Unlike with YMA only, the LIS group showed the highest frequencies only in the case of the patellofemoral and talocrural joints, while joint changes were more frequent in the NRD group for the acetabulofemoral joint (45%), and in the RD group for the tibiofemoral joint (42%). This joint showed the largest difference, between the RD group and the LIS group (22%). There was, however, no statistically significant difference between groups. We also observed that the frequencies were closer between the RD and NRD groups than compared to the LIS group.

Regarding the perifoveal osteophytes on the femoral head, in particular, the frequency was higher in the RD (57%) and NRD groups (53%), compared to the LIS group (34%; Table 29).

This difference was statistically significant (p = .032), even if the pairwise comparisons with corrected p values did not indicate any significant difference between pairs of groups. There was no significant difference between sides.

I.B.2. Bilateral asymmetry

As for the EC, we used paired bones from individuals in all adult age categories for the analysis of bilateral asymmetry.

The results are shown in Table 30. In general, there was no strong asymmetry within each group. The joint that was concerned the most by asymmetry was the acetabulofemoral joint (RD, 21%; NRD, 15%; LIS, 16%), with a higher frequency of joint changes on the left side in the RD and LIS groups, and a higher frequency of joint changes on the right side in the NRD groups. These differences were, however, small, and based on a rather limited number of observations. There was no statistically significant difference in the pattern of asymmetry between groups. Regarding the perifoveal osteophytes on the femoral head, there was also no strong side dominance within each group, nor was there any statistically significant difference in the pattern of asymmetry between groups (Table 31).

Results of the analysis of morphological variants of the femur

I.C.1. Intergroup comparisons

We could observe a total of 295 (27%) morphological variants of the femur out of 1075 observable sites. There was no significant difference between sides. There were more variants observed in the RD and NRD groups than in the LIS group (37%, 31%, and 22%, respectively, when left and right were combined; Table 32). The difference between the 3 groups was statistically significant, regardless of the side, and pairwise comparisons with corrected p values revealed that this significant difference concerned the RD and LIS groups (p adjusted = .002), and the NRD and LIS groups (p adjusted = .006). Those morphological variants concerned a total of 101 individuals (94%) among the entire sample of 107 who were considered as observable (i.e., when at least half of the sites were observable on each side). There was no significant difference between sides. A higher proportion of individuals was affected by at least one morphological variant in the RD group (100%) compared to the NRD (93%) and LIS groups (93%; Table 33). This difference was not statistically significant (p = .739), nor was it when individuals were considered separately depending on if they were affected on their left or right side (p = .325 and p = .681, respectively). The frequencies of morphological variants of the femur observed in each group and the results of the statistical comparisons between groups are shown in Table 34 and Figure 28. * indicates statistically significant differences between groups (see Table 34)

The morphological variant that was the most frequently observed in the entire sample is the anteroiliac plaque (FEM V2, 75%), while the least frequently observed was Allen's fossa (FEM V3, 9%). There was no statistically significant difference between sides, even if we notably noted a higher frequency of FEM V2 on the right side (89% versus 54% on the left side) in the RD group. The highest frequencies were found in the RD group for three morphological variants: Poirier's facet (FEM V1), the third trochanter (FEM V5), and the hypotrochanteric fossa (FEM V6). The NRD group showed the highest frequencies for Allen's fossa and the posterior cervical imprint (FEM V4), while the LIS group showed the highest frequencies for the anteroiliac plaque. These differences were statistically significant only for FEM V1, FEM V5, and FEM V6. Pairwise comparisons with corrected p values revealed that FEM V1 was significantly more frequent in the RD group (55%) than in the NRD (15%) and LIS groups (16%) for the left side, in particular (p adjusted = .043 for each). The frequency of FEM V5 was significantly higher in the RD (67%) and NRD (49%) groups than in the LIS group (12%; p adjusted < .001). FEM V6 did not show any significant difference between pairs of groups, but the frequency was higher in the RD (18%) and NRD (14%) groups than in the LIS group (5%).

I.C.2. Bilateral asymmetry

Analyzing only paired femurs, we did not observe any strong asymmetry within each group (Table 35). The morphological variant that was concerned the most by asymmetry was the posterior cervical imprint (FEM V4), with 11% in the RD group (left-side dominance), 13% in the NRD group (right-side dominance), and 4% in the LIS group (2% of left-side dominance and 2% of right-side dominance). There was no statistically significant difference in the pattern of asymmetry between groups.

FEM V2 R = L 6 86% 31 94% 97% .121 R > L 1 14% 0 0% 0% L > R 0 0% 2 6% 3% N pairs 7 33 FEM V3 R = L 8 100% 30 97% 97% .796 R > L 0 0% 1 3% 0% L > R 0 0% 0 0% 3% N pairs 8 31 FEM V4 R = L 8 89% 20 87% 95% .144 R > L 0 0% 3 13% 2% L > R 1 11% 0 0% 2% N pairs 9 23 FEM V5 R = L 10 91% 28 97% 97% .344 R > L 1 9% 0 0% 0% L > R 0 0% 1 3% 3% N pairs 11 29 FEM V6 R = L 11 100% 36 97% 100% .552 R > L 0 0% 0 0% 0% L > R 0 0% 1 3% 0% N pairs 11 37
Fisher's exact test, two-sided; L, left side; R, right side; asymmetry calculated as right side minus left side; R = L, equal scores; R > L, right score higher; L > R, left score higher

Results of the analysis of vertebral changes

I.D.1. Schmorl's nodes

A total of 95 individuals had observable and identifiable vertebrae from the first thoracic to the first sacral one, and 77 (81%) of them were affected by at least one Schmorl's node (SN) on the superior or inferior endplate of a vertebra. The frequency of individuals with SN was higher concerning the lower thoracic vertebrae (from the seventh to the twelfth) and it was lower regarding the upper thoracic vertebrae (Table 36). This difference was statistically significant for the NRD (Fisher's exact test, p = .002) and LIS groups (p < .001) but not for the RD group (p = .286). In details, in the NRD group, there were significantly more individuals with SN at the lower thoracic level compared to the upper thoracic one (p adjusted = .002), and at the lower thoracic level compared to the lumbar level (p adjusted = .047). It was the same situation in the LIS group (p adjusted < .001 in both cases). Still focusing on the frequency of individuals affected by SN (Table 36), we also observed higher frequencies of affected individuals in the RD group at all levels, while the lowest frequencies were found in the LIS group. There was no statistically significant difference between groups, but we noticed rather large differences between the RD group and the LIS group, in particular, at the upper thoracic and lumbar levels (50% versus 20% with p adjusted = .051, and 58% versus 30% with p adjusted = .055, respectively). The frequency of individuals with SN was more homogenous between groups at the lower thoracic level. The frequencies of vertebrae affected by SN in each group according to their size (small or large) and location, and the results of the statistical comparisons between groups are shown in Table 37, Figure 29, 30, and 31. A total of 1592 vertebrae from the first thoracic to the first sacral one could be observed and identified in the entire sample, among which 441 (28%) were affected by at least one SN. In the same way as for the analysis of frequencies of affected individuals, we observed more SN at the lower thoracic level, and less at the upper thoracic level (Figure 31). There were also more SN at the thoracic vertebrae pooled together than at the lumbar level. The NRD and RD groups showed the highest frequencies at all levels.

There were 350 cases of small SN (22%) and 91 cases of large SN (6%) in the entire sample. Small and large SN were both found in higher frequencies in the NRD and RD groups (Table 37; Figure 29, 30, and 31). Small SN were mostly found at the 8th and 9th thoracic vertebrae (53% and 47%, respectively), while large SN were mostly located at the 11th and 10th thoracic vertebrae (17% and 15%, respectively). Taking the size of SN into account (absence, presence of small SN, presence of large SN), we observed a statistically significant difference between groups at all levels (Table 37), and pairwise comparisons with corrected p values revealed that this difference concerned the NRD and LIS groups (as well as the RD and LIS groups when all vertebrae were taken together). Looking at each vertebra separately, only the 12th thoracic and 1st lumbar vertebrae showed significant differences between groups, and the main differences were found between the NRD and LIS groups (Table 37; Figure 30). More precisely, we observed the influence of the size of SN. At various levels, there was, indeed, a larger difference observed between groups, and especially between the NRD and LIS groups, considering large SN compared to small SN (Table 37; Figure 30 and31). This was the case at the 12th thoracic vertebra (38% versus 33% for small SN, and 22% versus 2% for large SN), and at the 1st lumbar vertebra (31% versus 21% for small SN, and 19% versus 2% for large SN), as well as for the entire lower thoracic level, from the 7th to the 12th vertebra (41% versus 41% for small SN, and 20% versus 6% for large SN). Furthermore, when the presence of small SN only was considered (Table 37; Figure 30), we observed only a statistically significant difference between groups concerning the 1st lumbar vertebra (p = .049), while, with large SN only, we observed a significant difference between groups for the 11th (p = .018) and 12th (p = .016) thoracic vertebrae, as well as for the 1st lumbar vertebra (p = .031). With p values corrected for pairwise comparisons, those differences were significant between the NRD and LIS groups for large SN observed on the 11th (p adjusted = .034) and 12th (p adjusted = .023) thoracic vertebrae. In general, the distribution of SN by vertebra and according to size was more similar between the RD and NRD groups, compared to the LIS group (Table 37; Figure 29, 30, and 31).

Figure 31. Frequency and distribution by grouped vertebrae and by size of Schmorl's nodes on the thoracic (T), lumbar (L), and the first sacral (S) vertebrae in the Hungarian groups with (RD) and without riding deposit (NRD), and the comparison group from Lisbon (LIS).

There were statistically significant differences at all levels between groups taking size difference into account (see

I.D.2. Spondylolysis

On a total of 1835 vertebrae (from the 3rd cervical to the 1st sacral vertebra) that could be identified and observed for this trait, we observed only 12 (0.7%) reliable cases of spondylolysis in the entire sample. Only the 2nd, 4th, and 5th lumbar vertebrae, as well as the 1st sacral vertebra, were affected, the 5th lumbar being the most frequently affected (8.5% in the entire sample). Six cases were found in the LIS group, and 6 were found in the NRD group. There were 6 cases of unilateral spondylolysis and 6 cases of bilateral spondylolysis (3 in each group).

Considering the extremely low number of observations for this trait, no further analysis was performed.

Results of the analysis of traumatic lesions

Reliable signs of fractures were observed on 38 individuals (33%) out of 114 ones composing the entire sample. The metacarpals and hand phalanges were the most affected (11%), followed by the ribs (10%), and the clavicle (6%), while the head (skull and mandible), sacrum, patella, and tarsal bones were not affected. Considering anatomical regions, the upper limb was the most affected (21%), followed by the thorax (ribs, 10%), and the lower limb (8%).

Intergroup comparisons revealed that the frequency of fractures was higher in the RD group (41%), compared to the NRD (34%), and the LIS groups (30%; Table 38 and Figure 32). It was the case only for the upper limb (35%, 24%, and 13%, respectively), while frequencies of fractures in the thorax were more equivalent between groups (9%, 9%, and 11%, respectively), and there were no fractures in the lower limb for the RD but 10% and 9% in the NRD and LIS groups, respectively. However, the only statistically significant difference was observed in the case of the clavicle, and pairwise comparisons with corrected p values indicated that there were significantly more clavicle fractures in the RD group (24%) than in the LIS group (0%, p adjusted = .013). We observed a large difference between the upper limb (35%) and the lower limb (0%) in the RD group but pairwise comparisons with corrected p values did not reveal that it was significant (p adjusted = .055). In contrast, there was only little difference between the upper limb and the lower limb in the NRD group (24% versus 10%, respectively), and in the LIS group (13% versus 9%, respectively). More precisely, considering the distribution of fractures within each group, the LIS group was the most homogenous, with an approximate balance of traumas according to the anatomical region, while 61% of the fractures in the NRD group were found in the upper limb, which increased to 89% in the RD group (Figure 33). In addition, we observed 10 cases of polytraumatism, where different bones or groups of bones considered in the study (as presented in Table 13), were affected by a fracture. There were 2 cases in the RD group, 6 in the NRD group, and 2 in the LIS group. Only one individual, from the NRD group, showed a fracture both at the upper and lower limb, while 2 individuals, also from the NRD group, had fractures on the same bone on both sides (the radius for one, and the clavicle for the other).

Results of the osteometric analyses

Index of ovalization of the acetabulum

II.A.1. Inter-and intraobserver agreement evaluation

Inter-and intraobserver agreement tests relied on 15 pairs of coxal bones selected randomly in the collection of Sárrétudvari-Hízóföld. There was a very good concordance between the series of measurements taken by Observer A and Observer B for the horizontal and vertical diameters of the acetabulum (Table 39). The mean absolute difference was indeed close to 1 mm in each case and the concordance correlation coefficient was superior to .900, which is considered as very satisfying. Additionally, we observed an excellent concordance for both diameters between the 2 series of measurements taken by Observer A, with a mean absolute difference not higher than 0.5 mm and concordance correlation coefficients superior to .970.

The concordance was almost perfect in the case of the horizontal diameter, with a coefficient of .993.

II.A.2. Intergroup comparisons

The preservation of the coxal bones was a limiting factor in the Hungarian archaeological groups, and in the RD group, in particular. The composition of the samples of acetabula for which the index of ovalization of the acetabulum (IOA) could be calculated is presented in Table 40. The index values were compared between each group, for the left and right acetabula taken separately and combined, without considering if one or both sides were observable in an individual (Table 41 and42; Figure 34). 42)

In the entire sample, the acetabula were not circular on average, but they tended to be a bit higher than wide (IOA lightly superior to 1), which corresponds to a normal morphology [START_REF] Bräuer | Anthropologie, Handbuch der vergleichenden Biologie des Menschen[END_REF]. The RD group was characterized by higher index values, including a higher median value, and by a greater variation (especially interquartile range), compared to the NRD and LIS groups, which showed rather similar distributions (Table 41; Figure 34). The differences were statistically significant between groups when left and right indices were combined (p = .025), and pairwise comparisons with corrected p values indicated that the significant differences were found between the RD and LIS groups (p adjusted = .024), in particular (Table 42). The acetabula were significantly higher and narrower (i.e., vertically ovalized) in the RD group. There was also a borderline significant difference between the RD and NRD groups (p adjusted = .050).

II.A.3. Bilateral asymmetry

As a further step, we evaluated the bilateral asymmetry of the acetabular shape, excluding, in that case, the individuals with only one observable acetabulum. In all groups, we observed a bilateral asymmetry, although it was not significant (Table 43). This asymmetry was however inverted in the case of the RD group compared to the NRD and LIS groups (Table 43;

Figure 35). Although the median and the variation were greater on the left side concerning the RD group, the spread of the values appeared to be higher on the right side in the two other groups (median and interquartile range in particular). Thus, the acetabula tended to exhibit a more important vertical ovalization on the left side in the RD group and on the right side in the NRD and LIS groups. We also calculated the difference between the right and left index values for each pair of acetabula to compare the degree and direction of bilateral asymmetry between groups (Table 44; Figure 36). The tendencies concerning the bilateral asymmetry were confirmed, with a negative median in the RD group and a positive median in the NRD and LIS groups, respectively. The left acetabula in the RD group appeared to be higher and narrower than the right ones, but they tended to be shorter and wider than on the right side in the NRD and LIS groups. While the differences between groups were not significant (p = .276), we observed that the direction of the asymmetry differed between the RD and the other groups.

II.B.1. Intergroup comparisons

The description of the other indices that were calculated on the lower limb bones is shown in Table 14. The index values were compared between each group, for the left and right values taken separately and combined, without considering if one or both sides were observable in an individual. The summary statistics of the indices of shape and robusticity are shown in Table 45 and the results of the statistical comparison are presented in Table 46. A total of 2430 index values could be calculated in the entire sample and were included in the analysis. On a total of 14 indices that were calculated, higher values were observed for half of them in the RD compared to the NRD and LIS groups, while 4 indices showed higher values on average in the NRD group, and 3 showed higher values in the LIS group. Statistically significant differences were reached for a majority of these indices (12/14), including FEM I1, for which there was a borderline significant difference between groups (p = .050). Pairwise comparisons with corrected p values revealed significant differences between pairs of groups for the eleven other indices. For a majority of these indices (10/11), we found a significant difference between the NRD and LIS groups, in particular, while, in addition, there was also a significant difference between the RD and LIS groups for 6 of them. Two indices only indicated a significant difference between the RD and NRD groups: the index values were lower in the RD group for TIB I2 and higher for TAL I2.

II.B.2. Bilateral asymmetry

As a further step, we evaluated the bilateral asymmetry, excluding, in that case, for each index, the individuals with only one observable side. Summary statistics of the paired index values are shown in Table 47, and the results of statistical tests are presented in Table 48. For a majority of indices, there was no significant bilateral asymmetry, even if, in general, more right index values tended to be higher. Five indices only revealed a statistically significant difference between sides. FEM I2 was significantly higher on the right side in the RD and LIS groups (p = .040 and p = .014, respectively), FEM I4 was significantly higher on the left side in the LIS group (p = .002), FIB I1 was significantly higher on the right side in the NRD group (p = .042), and TAL I3 was significantly higher on the left side in the RD group (p = .027). TIB I1 was significantly asymmetrical in all groups, with a right-side dominance. We also calculated the difference between the right and left index values for each pair of values to compare the degree and direction of bilateral asymmetry between groups (Table 49).

There was no statistically significant difference in the bilateral asymmetry between groups. In general, the direction of the asymmetry was similar for each index. Only few cases of inverted direction were found between the RD group and the two others (FEM I1 and FEM I5), between the NRD group and the two others (TIB I1 and TAL I2), and between the LIS group and the two others (TAL I3). In this chapter, we will first discuss the results of each type of analysis specifically, and then present general interpretations regarding the methodological and ethnoarchaeological aspects of this research, as well as general limitations and suggestions for future research.

Entheseal changes

Young and mature adult individuals

Based on the anthropological literature on horse riding and taking into consideration the muscle functions involved during the practice of horse riding, we selected thirteen entheses of the lower limb (see Chapter 2, III.A.1; Table 9). Entheseal changes (EC) and age being closely related, two series of analyses were performed: one with young and mature adult individuals (YMA) only, and the other one with individuals in all adult age categories. When including YMA only, three entheses showed significant differences between groups, and the first element that we can highlight is that these differences occurred only between each of the Hungarian groups, with (RD) and without riding deposit (NRD), and the group from the modern documented collection from Lisbon (LIS). There was no significant difference between both Hungarian groups, which suggests that there was no major difference in their use of lower limb muscles. If only the Hungarian group with riding deposit was practicing horse riding, we would expect to observe differences with the group without riding deposit for some entheses related to muscles strongly involved in this practice. If we assume that EC are influenced, at least in part, by activity, then these first results tend to indicate that the practice of horse riding was frequent in both Hungarian groups, regardless of the goods in the grave. This point will be discussed further below (see IX below).

Concerning the three entheses that showed significant differences between groups, for the first one, EC at the tibial tuberosity (TIB E1) were significantly higher in the group from Lisbon while they were never observed in the Hungarian groups. This suggests that this enthesis is not influenced by the practice of horse riding. The tibial tuberosity is the insertion site of the quadriceps femoris, related to hip flexion and knee extension (Putz & Pabst, 2001). In riding with long stirrups, these muscles push the heel down by putting more weight through the stirrups, while with short stirrups, they contribute to stability by holding the body weight and controlling the position of the seat [START_REF] Willson | The riding muscles and their function in riding[END_REF]. We can hypothesize that the absence of changes at the tibial tuberosity might be related to the fact that the four muscles composing the quadriceps femoris insert first to the patella via the quadriceps tendon, which becomes then the patellar ligament. The effect of activity on the tibial tuberosity could therefore be diminished.

There was however no significant difference for the insertion of the quadriceps femoris on the anterosuperior part of the patella, which indicates that this group of muscles or, at least, that the insertion sites (as opposed to the origin sites) of these muscles may not represent a good indicator for the practice of horse riding.

The second enthesis was the adductor tubercle (FEM E7). Although significant differences were observed between the three groups, pairwise comparisons did not identify significant differences between paired groups. We observed, nevertheless, that EC were higher in the Hungarian groups, and especially in the RD group (38%), compared to the LIS group (5%).

The adductor tubercle is the insertion site of the adductor magnus on the distal femur. This muscle controls for hip adduction, lateral rotation, flexion (anterior part), and extension (posterior part), and is one of the main muscles used in riding (Putz & Pabst, 2001;[START_REF] Pugh | Overuse injuries in equestrian athletes[END_REF][START_REF] Djukic | Bone macromorphology at muscle attachment sites: Its relationship with the microarchitecture of the underlying bone and possible implications for the reconstruction of habitual physical activities of past populations[END_REF][START_REF] Baillif-Ducros | La pratique de la monte à cheval au haut Moyen Âge (fin Ve-VIIe siècle) dans le nord-est de la Gaule. État des connaissances archéologiques[END_REF]. With the other adductor muscles, it keeps the legs pressed against the horse's flanks while riding, and these muscles are often overworked by riders [START_REF] Willson | The riding muscles and their function in riding[END_REF]. Adductor strain is the first limiting factor in professional riders and tendinopathies can be a consequence of this overwork (Auvinet, 1980a;[START_REF] Auvinet | Quelques aspects de la pathologie chez le cavalier, prévention 6ème journée d'étude "Quoi de neuf en matière d'etudes et de recherches sur le cheval ?[END_REF]. The differences observed between groups can therefore well be explained by the practice of horse riding in the Hungarian groups. We should however remind that the adductor tubercle is a fibrous enthesis, for which the correlation with activity is more debated than for the fibrocartilaginous type of entheses (see Chapter 1, I.C, and Chapter 2, III.A.1). As the normal aspect of fibrous entheses is not fully acknowledged, the scoring of EC at this site may be more difficult and subjective, and this enthesis would require further methodological investigation.

The third enthesis showing significant differences in EC between groups in the YMA sample was the calcaneal tuberosity (CAL E1), and it is the one that presented the largest differences. EC at this site were much higher in the Hungarian groups compared to the LIS group (69% in NRD, 56% in RD, and 11% in LIS, with sides combined), even when each side was taken separately. Pairwise comparisons also revealed that the significant differences were between the RD and LIS groups, and the NRD and LIS groups. The calcaneal tuberosity is the insertion point of the calcaneal (or Achilles) tendon, which attaches the calf muscles (triceps surae: soleus, gastrocnemius; and plantaris muscle) to the calcaneus. These muscles are involved in ankle plantar flexion, talotarsal supination, as well as knee flexion (Putz & Pabst, 2001). In riders, the gastrocnemius, in particular, needs to be long, and thus regularly stretched, as the heel is pushed down below the level of the toes [START_REF] Willson | The riding muscles and their function in riding[END_REF]. With this in mind, the practice of horse riding in the Hungarians groups seems to be a very reasonable explanation for the large differences observed with the LIS group.

These results are of great interest but we must keep in mind that sample sizes were very limited including only YMA individuals, which should lead to consider these interpretations with some caution.

Individuals in all adult age categories

Analyses including individuals in all adult age categories were characterized by higher sample sizes and revealed even more significant differences between groups. Most importantly, there was still no significant difference observed between each Hungarian group, but only between the Hungarian groups and LIS group. This supports the observations made on the YMA sample, and especially the hypothesis that both Hungarian groups might have practiced horse riding in a similar way, regardless of the goods in graves. The three entheses that were previously noted (FEM E7, TIB E1, and CAL E1) were still showing identical differences between groups, and they were complemented in this analysis by six more entheses, with five of them revealing significant differences between paired groups. The anterior inferior iliac spine (COX E1), the ischial tuberosity (COX E2), the trochanteric fossa (FEM E3), the linea aspera (FEM E6), and the soleal line (TIB E2) were all showing significantly more EC in the NRD group compared to the LIS group, and, for the trochanteric fossa, the adductor tubercle, and the calcaneal tuberosity, also in the RD group compared to the LIS group. The function of the quadriceps muscles (rectus femoris, vastus medialis, vastus intermedius, and vastus lateralis, notably involved in the anterior inferior iliac spine and the linea aspera), and the adductors (linea aspera, adductor tubercle) was already discussed above. The hamstrings (involved in the ischial tuberosity) notably bend the knee and extend the hip (Putz & Pabst, 2001); they contribute to stabilizing the heel and lower leg against the horses' side, and, this way, to keep the seat deep in the saddle. Riders have very tight and stiff hamstring muscles [START_REF] Willson | The riding muscles and their function in riding[END_REF].

The internal (notably involved in the linea aspera) and external rotators of the hip (involved in the trochanteric fossa) rotate the thigh inwards and outwards, respectively, thus controlling for the direction of the toes, which should keep pointing forward in riding [START_REF] Willson | The riding muscles and their function in riding[END_REF]. The soleus muscle (involved in the soleal line and the calcaneal tuberosity), part of the triceps surae, contributes to ankle plantar flexion and talotarsal supination, as mentioned previously (see I.A above). All these entheses are origin or insertion sites of muscles that are essential in riding, and we can therefore assume that the higher frequencies of EC observed in the Hungarian groups may be related to the regular practice of horse riding.

Although the analysis includes more individuals than with the YMA sample, we must remind that the presence of old adult individuals may influence the results, the development of EC being closely related to aging. As explained previously (see Chapter 2, III.C.2), the fact that old adults are present in all groups should still, however, allow making comparisons to identify differences between groups. Due to the larger sample sizes, this second analysis provides more information than the first one. If this complementary information must be considered with caution, it confirms the observations performed with young and mature adult individuals only.

Further interpretations and considerations

In addition to the previous remarks, the absence of significant differences for other entheses also deserves a comment. Considering the function of the muscles that are attached there, we would expect some entheses to be involved in horse riding, and consequently, to show significantly more EC in the Hungarian groups. This is the case, for instance, for the gluteals.

In the analysis with all adult individuals, the anterior surface of the greater trochanter (FEM E1), insertion site of the gluteus minimus, is the only enthesis related to a gluteal muscle that presents a significant difference between groups, but pairwise comparisons did not provide more precision. For each gluteal muscle insertion site (FEM E1, as well as the superior lateral surface of the greater trochanter, FEM E2, and the gluteal tuberosity, FEM E5), frequencies of EC were higher in the NRD group, and there was no EC observed at the greater trochanter (both anterior and superior lateral surfaces) in the RD group. Gluteal muscles notably extend, abduct, and rotate the hip and control the amount of bend in the trunk (Putz & Pabst, 2001;[START_REF] Willson | The riding muscles and their function in riding[END_REF]. The lack of significant differences between the Hungarian groups and the LIS group may indicate that the individuals from Lisbon were practicing activities that also involved these muscles. Gluteals are active while walking or climbing stairs, and are notably strong running muscles [START_REF] Willson | The riding muscles and their function in riding[END_REF][START_REF] Djukic | Bone macromorphology at muscle attachment sites: Its relationship with the microarchitecture of the underlying bone and possible implications for the reconstruction of habitual physical activities of past populations[END_REF]. Riders use them in the jumping position and in the rising trot [START_REF] Willson | The riding muscles and their function in riding[END_REF], which might concern more modern riders than populations from the 10th century. Similarly, the lack of significant differences observed for the lesser trochanter (FEM E4), insertion site of the iliopsoas (iliacus, psoas major, psoas minor), may indicate that it is not a good indicator for the practice of riding. These muscles are important for standing, walking, and running, and they control for lumbar lateral flexion and extension (increasing lumbar lordosis), and for hip flexion and rotation (Putz & Pabst, 2001). It is therefore possible that other activities or working postures adopted by the individuals from Lisbon influenced the development of EC at this site. The effect of aging could also partly explain the results observed for the gluteal and iliopsoas muscles.

No enthesis revealed high frequency of bilateral asymmetry and there was no significant difference in the pattern of asymmetry between groups. This indicates that no activity or posture practiced in each group led to the asymmetrical development of EC. Riding is generally considered as involving profound symmetrical stresses between muscles, since both legs are involved [START_REF] Willson | The riding muscles and their function in riding[END_REF][START_REF] Djukic | Morphological appearance of muscle attachment sites on lower limbs: Horse riders versus agricultural population[END_REF]. The analysis of bilateral asymmetry was however performed on all individuals, including older adults, which could confound the results.

Although our results must be taken with caution, they are rather consistent with prior methodological studies which precisely investigated the relationship between EC and the practice of horse riding. Specifically, [START_REF] Tichnell | Invisible Horsewomen: Horse Riding and Social Dynamics on the Steppe[END_REF] performed multiple comparisons between Pre-versus Post-Contact Arikara populations as well as between Post-medieval British cityversus country-dwelling populations. The author observed significant correlations with horse riding for two entheses, the gluteal tuberosity and the adductor tubercle, and also observed that the greater and lesser trochanters had no predictive value for identifying horse riders. Later on, [START_REF] Djukic | Bone macromorphology at muscle attachment sites: Its relationship with the microarchitecture of the underlying bone and possible implications for the reconstruction of habitual physical activities of past populations[END_REF] observed significantly more pronounced EC at the ischial tuberosity, linea aspera, and the adductor tubercle on the femur, in horse riding populations (Avars) compared to agricultural populations from medieval Serbia. The author considered the EC at the adductor muscles attachment site, in particular, as the most reliable indicators for the identification of riders as the action of keeping the legs together is not common in other daily activities than horse riding [START_REF] Djukic | Morphological appearance of muscle attachment sites on lower limbs: Horse riders versus agricultural population[END_REF].

With the exception of the anterior inferior iliac spine (COX E1), all other EC that we analyzed were also mentioned in the literature as being associated with horse riding (see Chapter 1, II.D.1; Table 3), but it was either not in the frame of systematic methodological investigations, either the entheseal changes were simply assumed to be related to horse riding, either there was no evidence for the practice of this activity in the concerned individuals and populations, or studies relied on single individuals, which does not give credit to the reliability of the relationship between these EC and horse riding.

We will discuss the general contributions and limitations of this research in a further section (see X below), and the main limitations to be considered in the analysis of EC, in particular, were discussed previously (see Chapter 1, I.C). Among various aspects, it is clear that the main challenge that we had to take into account to be able to make interpretations in terms of physical activities in past populations was the multifactorial etiology of entheseal changes (see XI below).

Joint changes

As for the analysis of entheseal changes, the correlation between the development of joint changes and aging led us to perform two series of analyses, one including young and mature adult individuals (YMA) only, and another one, with larger sample sizes, including individuals in all adult age categories. The main articular surfaces of the lower limb bones were combined into the acetabulofemoral, patellofemoral, tibiofemoral, and talocrural joints (see Chapter 2, III.A.2; Table 10). There were almost no significant differences between groups. In the analysis with the YMA sample only, we observed only a significant difference between the three groups for the frequency of all joint changes together when both sides were combined. Pairwise comparisons did not provide more precision, even if we observed more joint changes in the group from the documented collection from Lisbon (LIS) than in the Hungarian groups, and in the group with riding deposit (RD), in particular. We observed, in fact, almost no joint changes in the RD group in the YMA sample. This may partly be related to the limited size of the sample used in this analysis. When including all individuals in a second analysis, frequencies of joint changes were much more similar between groups, and there was no significant difference. In addition, there was only light asymmetry observed in each group and for each joint, and no difference in the pattern of asymmetry between groups either.

Degenerative joint changes are commonly used to analyze variation in behavior and mobility between populations (see for instance Knüsel, 2000b;[START_REF] Jurmain | Bioarchaeology's Holy Grail: The Reconstruction of Activity[END_REF][START_REF] Schrader | Activity, Diet and Social Practice. Addressing Everyday Life in Human Skeletal Remains[END_REF], and see Chapter 1, I.B). Contrary to the analysis of entheseal changes, the results of the analysis of joint changes did not show differences that could possibly be related to the practice of horse riding in one or both Hungarian groups. As the practice of horse riding was very likely, at least for a part of the sample from the 10th century, and very unlikely in the group from Lisbon (see Chapter 2, II.C.1), we can assume that joint changes of the lower limb are not good indicators for this activity. The lack of specificity of these changes could explain these results, as various activities and postures might lead to the development of changes at those weightbearing joints. These results could also be related to the fact that we used a binary scoring method for the analysis (see Chapter 2, III.A.2), which did not allow identifying differences according to the severity of the joint changes. We can, however, highlight that joint changes were scored as present only when clearly discernible, hence discarding very light changes. In addition, during our examination of the entire sample, we observed only a few cases of severe joint changes and eburnation.

Besides the main joints of the lower limb, we also analyzed, independently, the osteophytes at the fovea capitis of the femoral head. If the analysis in the YMA sample did not reveal any difference between groups, the analysis with all individuals showed a significant difference between groups when both sides were combined. Pairwise comparisons did not provide further precision, but there were more perifoveal osteophytes in the RD (57%) and NRD groups (53%), compared to the LIS group (34%). Considering the presence of old adults in the sample and the close correlation between such osteophytes and age, we must be cautious in the interpretation of this observation.

In a methodological study of Merovingian series from northeastern Gaul, including some individuals with riding-related grave goods, Baillif-Ducros (2018) systematically scored the presence of "osteophytic hip" when there was the combined presence of perifoveal osteophytes and osteophytosis on the margin of the femoral head. The author noted that this criterion was not specific to riders but suggested that it could be a good indicator when observed in association with other changes such as Poirier's facet and the ovalization of the acetabulum, especially if it occurred in young adult individuals. This would be related to the effect of the position of the rider on the hip joint. Similarly, the author scored the presence of osteoarthritis at the femoropatellar joint and suggested that this criterion completes the previous skeletal changes for the identification of horse riding, and the use of stirrups, in particular, in young and mature adult individuals.

As mentioned above, our results did not go in this direction since there was no significant difference between groups for the acetabulofemoral (without perifoveal osteophytes) and patellofemoral joints, and especially in the sample of young and mature adult individuals. The absence of differences between groups at the knee joint is particularly noticeable since the populations from the Hungarian Conquest period were using stirrups, as demonstrated by the archaeological goods discovered in the cemeteries [START_REF] Nepper | Hajdú-Bihar megye 10-11. századi sírleletei I-II. (Magyarország honfoglalás és kora Árpád-kori sírleletei 3)[END_REF][START_REF] Révész | The cemeteries of the Conquest period[END_REF]. The analysis of joints of the upper limb (such as the shoulders) may provide more information as the upper body plays an essential in riding too [START_REF] Willson | The riding muscles and their function in riding[END_REF].

Morphological variants of the femur

Morphological variants were investigated as some of them are suspected to be influenced by mechanical aspects and were considered as being related to the practice of horse riding, in particular (see Chapter 1, II.D.1; Table 4; and Chapter 2, III.A.3). Six morphological variants of the femur were analyzed and compared between groups, in the entire sample of individuals.

Significant differences between groups were observed for three morphological variants (Table 34). Poirier's facet (FEM V1) and the third trochanter (FEM V5) were significantly more observed in the Hungarian group with riding deposit (RD) compared to the group from Lisbon (LIS). The third trochanter was also more frequent in the Hungarian group without riding deposit (NRD) compared to the LIS group, while we observed one of the rare significant differences between the RD and NRD groups for Poirier's facet (left side only). There was also only little bilateral asymmetry for each variant in each group, and no significant difference in the pattern of asymmetry between groups.

We highlight that our study is one of the few to distinguish the variations of the anterior aspect of the femoral head-neck junction, and especially Poirier's facet and the anteroiliac plaque [START_REF] Villotte | Some remarks about femoroacetabular impingement and osseous non-metric variations of the proximal femur[END_REF][START_REF] Radi | Variation of the anterior aspect of the femoral head-neck junction in a modern human identified skeletal collection[END_REF], which were often mentioned in the anthropological literature on horse riding but rarely distinguished (see Chapter 1, II.D.1). Based on this distinction and our observations, it seems that both features are influenced, at least partly, by different factors, since the anteroiliac plaque (FEM V2) was observed in high frequency in all groups. It was furthermore more present in the LIS group compared to the Hungarian groups, even if there was no significant difference. Our results suggest that the anteroiliac plaque, if related to activity, is not specific to horse riding. It could, for instance, result from repeated postures involved in various other activities that have been practiced by the individuals from Lisbon. [START_REF] Jennings | Femoral neck activity and kneeling at a Byzantine monastery[END_REF] analyzed the presence of Poirier's facet, the anteroiliac plaque, Allen's fossa, and the posterior cervical imprint in femurs from a Byzantine monastery, and observed a significant asymmetry for the anteroiliac plaque only. The authors interpreted this observation as the consequence of repeated kneeling and genuflection among monks, which was consistent with historical and liturgical accounts.

Poirier's facet seems, however, to show a more promising relationship with the practice of horse riding, as it was significantly more frequent in the RD group compared to the LIS group, but not in the NRD group compared to the LIS group. As no, or little, interpopulation variation is expected between both Hungarian groups, these observations suggest a mechanical influence on the apparition of Poirier's facet, and the practice of horse riding in the RD group and absence of practice of riding in the LIS group is a reasonable and logical explanation in this context.

Among all studies that mentioned a possible link between Poirier's facet and horse riding, rare were those which relied on a systematic methodological investigation or on a sample of confirmed riders. In her methodological study of Merovingian series from northeastern Gaul, including some individuals with riding-related grave goods, Baillif-Ducros (2018) observed a significant difference for Poirier's facet between the individuals with and without riding deposit in their grave. In association with the osteophytic hip and the ovalization of the acetabulum, the author suggested that it represents a reliable indicator for the practice of horse riding. The appearance of Poirier's facet would indeed be a consequence of the femoroacetabular impingement related to the repeated sitting position of the rider, which involves a flexion of the hip.

The contact produced between the femoral head and the rim of the acetabulum by extreme flexion and abduction of the thigh would be a cause for the appearance of Poirier's facet [START_REF] Capasso | Atlas of Occupational Markers on Human Remains[END_REF]. With medical insights, [START_REF] Villotte | Some remarks about femoroacetabular impingement and osseous non-metric variations of the proximal femur[END_REF] provided a more precise explanation. Cam impingement (by opposition to pincer impingement) is caused by the movements of a non-spherical femoral head in the acetabulum during forceful movements, such as the flexion of the hip. More specifically, it would result from a "bump", an abnormal extension onto the femoral neck and increased thickness of the neck that is composed of subchondral bone and degenerative hyaline cartilage. This ossification would be stimulated by biomechanical forces (involved during flexion especially) and the extension of the articular surface of the head onto the neck, i.e., Poirier's facet, would correspond to the medial part of the bump, after the disappearance of soft tissues [START_REF] Villotte | Some remarks about femoroacetabular impingement and osseous non-metric variations of the proximal femur[END_REF]. From their investigation, the authors suggest that the morphological variants at the femoral head-neck junction could, indeed, be considered as possible activity-related markers.

Contrary to the analysis of entheseal changes and joint changes, the significant difference observed here between the RD and NRD group tends to indicate that there was a difference in the level of horse riding practice between them, except if other factors are involved. We must, for instance, note that, despite a recent redefinition of Poirier's facet and the anteroiliac plaque [START_REF] Radi | Variation of the anterior aspect of the femoral head-neck junction in a modern human identified skeletal collection[END_REF], it may sometimes be uneasy to distinguish them, and, specifically, to identify their simultaneous presence. This difficulty, as well as the rather small sample size in the RD group, compared to the other groups, may have partly influenced our results.

Concerning the third trochanter, large and significant differences between both Hungarian groups and the LIS groups could also be explained by the practice of horse riding as the gluteus maximus muscle is considered as a primary factor governing its expression [START_REF] Lozanoff | Third trochanter incidence and metric trait covariation in the human femur[END_REF][START_REF] Bolanowski | The occurrence of the third trochanter and its correlation to certain anthropometric parameters of the human femur[END_REF][START_REF] Ghosh | Incidence of third trochanter and hypotrochanteric fossa in human femora in Indian population[END_REF]. However, we already discussed that the gluteal muscles might not, in fact, be relevant muscles for the identification of horse riding in our sample, as we observed no significant differences between groups and as their functions are involved in other activities or postures (see I.C above). The etiology of the third trochanter is still debated, and genetic and environmental factors are among the possible causes for its apparition [START_REF] Ghosh | Incidence of third trochanter and hypotrochanteric fossa in human femora in Indian population[END_REF]. It was also notably suggested that this trait can be relevant for human taxonomy studies [START_REF] Lozanoff | Third trochanter incidence and metric trait covariation in the human femur[END_REF]. The possibility that the large differences observed between both Hungarian groups and the LIS group are due to interpopulation variation is, therefore, rather important.

Finally, in addition to Poirier's facet and the third trochanter, the hypotrochanteric fossa (FEM V6) showed a significant difference between the three groups (both sides combined) but not between paired groups, even if we observed that its frequency was higher in both Hungarian groups compared to the LIS group, in particular. The etiology of this trait is even more debated than for the third trochanter, and recent investigations highlighted how obscure are the causes of its apparition [START_REF] Ghosh | Incidence of third trochanter and hypotrochanteric fossa in human femora in Indian population[END_REF]. Our results do not allow determining if mechanical factors are more likely to have influenced this factor compared to genetic factors, in particular. The quasi absence of bilateral asymmetry observed for these traits is an argument toward a genetic influence.

It should furthermore be noted that we did not find any explicit mention of the hypotrochanteric fossa as a possible indicator for horse riding in the anthropological literature, and very rare ones regarding the third trochanter (see Chapter 1, II.D.1; Table 4). These traits were investigated here in an exploratory approach.

This analysis underlined how little is known regarding the etiology of morphological variants. This is notably due to the fact that most of them are asymptomatic and non-lethal. As few clinical studies are focusing on these aspects, most of our knowledge comes therefore from anatomical and anthropological literature [START_REF] Henderson | Musculo-skeletal stress markers in bioarchaeology: indicators of activity levels or human variation? A re-analysis and interpretation[END_REF].

Vertebral changes Schmorl's nodes

Although their etiology is still debated, Schmorl's nodes are commonly interpreted as 12). Significant differences were observed between groups at all vertebral levels, with higher frequencies in the Hungarian groups, and in the NRD group compared to the LIS group, in particular. Concerning individual vertebrae, there were significant differences for the twelfth thoracic and first lumbar vertebrae specifically, with notably a higher frequency of large nodes in the NRD group compared to the LIS group. We observed no significant differences between both Hungarian groups, which supports the results of the analyses of the entheseal changes and joint changes, and suggests that there was no major difference in behavior or mobility pattern between these groups.

Even though other factors (e.g., congenital defects, spinal diseases, vertebral morphology) could influence the apparition of Schmorl's nodes, they are particularly common in individuals, young ones especially, whose high-level physical activity imposes great stress on their lower spine, such as elite athletes [START_REF] Waldron | Palaeopathology[END_REF]. They could notably result from trauma related to hard physical activities, heavy lifting, or a fall from height (Mann & Hunt, 2013). In sports medicine, it is acknowledged that significant spinal loading forces and repetitive microtrauma over the years can cause disc herniations [START_REF] Pugh | Overuse injuries in equestrian athletes[END_REF]. Depending on the riding style, horse riding can cause high stresses on the vertebral column. The repetition of microtraumas on the vertebrae could lead to a fragilization of the outer ring of fibrous cartilage (annulus fibrosus) that surrounds the nucleus pulposus, which may ultimately result in disc herniations (Baillif-Ducros, 2018).

Schmorl's nodes are typically more frequent in lower thoracic and upper lumbar vertebrae, between the seventh thoracic and first lumbar vertebra [START_REF] Hilton | Vertebral end-plate lesions (Schmorl's nodes) in the dorsolumbar spine[END_REF][START_REF] Üstündağ | Schmorl's nodes in a post-medieval skeletal sample from Klostermarienberg, Austria[END_REF][START_REF] Dar | Schmorl's nodes distribution in the human spine and its possible etiology[END_REF]. This is related to the different movements of the vertebral column, which are not equally free in all portions (Üstündağ, 2009). The lumbar vertebrae allow only minimum axial rotation compared to the thoracic vertebrae, even though their mobility is limited due to the attachment of the ribs [START_REF] Üstündağ | Schmorl's nodes in a post-medieval skeletal sample from Klostermarienberg, Austria[END_REF][START_REF] Dar | Schmorl's nodes distribution in the human spine and its possible etiology[END_REF]. The transition between the stiffer thoracic level and the more mobile lumbar level results in structural weakness for torsional stress, which makes this region more prone to injuries (Üstündağ, 2009). We can also mention that the twelfth thoracic and first lumbar vertebrae are the most frequent seat of vertebral fractures, which indicates that this region may be relatively susceptible to stress [START_REF] Hilton | Vertebral end-plate lesions (Schmorl's nodes) in the dorsolumbar spine[END_REF].

In addition, regarding the size of Schmorl's nodes, it was previously demonstrated that the formation of large nodes could result from acute traumas, while small nodes would be more likely related to repeated microtraumas [START_REF] Takahashi | A Large Painful Schmorl's Node: A Case Report[END_REF][START_REF] Üstündağ | Schmorl's nodes in a post-medieval skeletal sample from Klostermarienberg, Austria[END_REF].

Based on all these considerations, the practice of horse riding represents a possible explanation for our results and the differences observed between the Hungarian groups and the group from Lisbon, where it is very unlikely that individuals were performing this activity.

In her study of Merovingian populations, Baillif-Ducros (2018) did not observe the presence of the Scheuerman's disease (notably characterized by a cuneiformization of the vertebrae and the presence of Schmorl's nodes), while its prevalence is high in modern riders [START_REF] Auvinet | Lombalgies et équitation[END_REF][START_REF] Humbert | L'équitation et ses conséquences sur le rachis lombaire du cavalier : à propos de 123 observations[END_REF]. The presence of Schmorl's nodes alone was not however discussed. She suggested that this difference may be explained by the fact that modern riders are looking for high-level sports performance, and are thus affected differently by the practice of horse riding. Earlier, Üstündağ and Deveci (2011) attributed a case of Scheuermann's disease to a trauma or repeated trauma related to vertical forces due to riding stress. The individual was found in an Islamic cemetery (13-14th century) with a horse skeleton as a co-burial.

A study of archaeological samples of Mongolian pastoralists also revealed that populations from the Xiongnu Empire and Mongol Empire, known for their mounted warriors, showed significantly higher rates of Schmorl's nodes compared to a sample from the Bronze Age, when pastoralism emerged [START_REF] Eng | Vertebral joint disease and trauma with horse riding among ancient Mongolian pastoralists[END_REF]. The relationship between Schmorl's nodes and the practice of horse riding was also suggested for other Mongolian pastoralists [START_REF] Karstens | A palaeopathological analysis of skeletal remains from Bronze Age Mongolia[END_REF], as well as in several other studies relying on presumed riding populations, such as Post-Contact

Native Americans [START_REF] Miller | The Effect of Horseback Riding on the Omaha and Ponca: Paleopathological Indications of European Contact[END_REF][START_REF] Sandness | Vertebral Pathology in Prehistoric and Historic Skeletons from Northeastern Nebraska[END_REF][START_REF] Reinhard | Trade, contact, and female health in Northeast Nebraska[END_REF][START_REF] Reinhard | Identifying Equestrian Skeletal Markers[END_REF], or Scythian warriors [START_REF] Wentz | Life on horseback: Palaeopathology of two Scythian skeletons from Alexandropol, Ukraine[END_REF]. In addition, a relatively high frequency of Schmorl's nodes was observed in young adult individuals from the Seventh Cavalry, who fought and died at the Battle of Little Bighorn on 25, June 1876, along with Lieutenant Colonel George A. Custer, during the American Civil and Indian Wars. These lesions occurred mostly in the lower thoracic and upper lumbar vertebrae and were attributed to axial trunk loading and compressional forces that could be related to horse riding, possibly accentuated by the lifting and carrying of heavy weapons and the use of hard saddles (Willey, 1997).

Sports medicine does not demonstrate the existence of an association between Schmorl's nodes and the practice of horse riding. This is partly due to the fact that their apparition seems to be influenced by other factors than activity or posture. Although previous anthropological studies often lack direct evidence of a link between the individuals and horse riding, they suggest that this activity could lead to the apparition of Schmorl's nodes. This hypothesis seems to be supported by our results.

Spondylolysis

Although spondylolysis was often used as an indicator of stress in past populations and was previously referred to as possibly being related to the practice of horse riding (see Chapter 2, III.A.4.b), we observed only few (12) cases of vertebrae affected by spondylolysis in our sample, with an equal distribution between the NRD and LIS groups. If this trait was positively associated with horse riding, we would have expected higher rates in the Hungarian groups, and at least some cases observed in the group with riding deposit.

Spondylolysis is considered as indicative of a fatigue fracture, and in sports medicine, it is common in young athletes, and especially in those whose practice involves repetitive hyperextension of the back. As for gymnasts, this is notably the case of riders, who absorb significant forces with their lumbar spine in extension [START_REF] Pugh | Overuse injuries in equestrian athletes[END_REF]. Spondylolysis can lead to spondylolisthesis, the anterior slippage of a vertebra out of its original position onto the inferior vertebra, which is not present in higher rates in professional riders than in the general population (3-5%;[START_REF] Auvinet | Lombalgies et équitation[END_REF][START_REF] Humbert | L'équitation et ses conséquences sur le rachis lombaire du cavalier : à propos de 123 observations[END_REF].

This and our results suggest either that spondylolysis is not related to horse riding or that it is not specific to this activity. Spondylolysis is also among the numerous skeletal changes for which etiology is still debated, possibly being influenced by genetic and other factors in addition to mechanical factors (see Chapter 2, III.A.4.b). In the end, it seems not to represent a good indicator for the practice of horse riding in past populations. We can nevertheless mention the fact that healed fractures may not necessarily be visible during macromorphological examinations of skeletal remains [START_REF] Merbs | Spondylolysis: its nature and anthropological significance[END_REF]. The use of radiographic methods might contribute to a better identification of this process, and thus, to a better understanding of this condition and its possible relationship with physical activity.

Traumatic lesions

Although macrotraumas can be considered as anecdotical, reflecting accidental wounds or interpersonal injuries, they can provide information on the lifestyles and behaviors in past populations, completed by the analysis of other types of skeletal changes (see Chapter 2, III.A.5). Concerning horse riding, sports medicine reveals that fractures are the second most common type of injuries, after soft tissue injuries, and that a majority of these fractures result from a fall from the horse [START_REF] Bixby-Hammett | Common injuries in horseback riding. A review[END_REF].

Our analysis of fractures on the upper and lower body reveals that the upper limb was the most affected anatomic region in our sample and that there were generally higher rates of fractures in the Hungarian groups compared to the group from Lisbon. This difference was statistically significant only for the clavicle and concerned the RD and LIS groups, in particular (Table 38). Fractures of the clavicle mainly occurred at midshaft and were visible due to the presence of a callus, angular deformity, and diaphyseal shortening (Figure 37).

In sports medicine, the injuries related to horse riding concern mostly the upper limbs (see for instance Baillif-Ducros, 2018, and see Chapter 1, II.B). This would notably be related to the attempt of self-protection that occurs during a fall. In the anthropological literature, fractures at almost all anatomical regions were at least once described as potentially related to the practice of horse riding, with more or less valid arguments, but the clavicle is one of the most cited elements (see Chapter 1, II.D.1; Table 5). Fractures at the clavicle midshaft often occur from falls from a moderate height, such as from a bicycle or horse [START_REF] Wedel | Broken Bones: Anthropological Analysis of Blunt Force Trauma[END_REF]. It was postulated that such fractures mostly result from a fall on the outstretched hand, but it was demonstrated that they could also result, for instance, from a blow to the point of the shoulder due to a fall with landing on the shoulder, or also from a direct trauma to the clavicle [START_REF] Wedel | Broken Bones: Anthropological Analysis of Blunt Force Trauma[END_REF].

Our results and these considerations suggest that the significant difference observed between groups for clavicle fractures could be a consequence of the practice of horse riding in the Hungarian group with riding deposit, at least. Among other studies, Khudaverdyan et al.

(2016) notably described a case of oblique fracture with angular deformity on one clavicle of an individual from a Late Iron Age cemetery in Armenia. The individual showed multiple trauma, and the pattern of lesions suggested, according to the authors, the practice of horse riding. The individual was, in fact, buried together with a horse.

The higher rates of fractures in the upper limb in both Hungarian groups, compared to the thorax (ribs) and the lower limb, also coincides with the observations from sports medicine on horse riders [START_REF] Bixby-Hammett | Common injuries in horseback riding. A review[END_REF][START_REF] Baillif-Ducros | La pratique de la monte à cheval au haut Moyen Âge (fin Ve-VIIe siècle) dans le nord-est de la Gaule. État des connaissances archéologiques[END_REF], while the distribution of fractures was equivalent between these three anatomical regions in the LIS group (Table 38;

Figure 33).

With the exception of a cut wound and symbolic or surgical trepanations in the Hungarian series, which were not scored in this analysis, we did not observe traumas of the head, in any group, while it could be expected in the case of the Hungarian groups if some individuals were practicing horse riding. The head is indeed the second element the most affected by macrotraumas related to horse riding in most of the studies on modern riders, and head injuries are also the first cause of death of riders [START_REF] Bixby-Hammett | Common injuries in horseback riding. A review[END_REF][START_REF] Baillif-Ducros | La pratique de la monte à cheval au haut Moyen Âge (fin Ve-VIIe siècle) dans le nord-est de la Gaule. État des connaissances archéologiques[END_REF]. This absence could partly be related to bone preservation in the archaeological materials.

Some traumas may also have not let osseous signs. Cerebral contusions are indeed among the most frequent lesions observed in modern riders and contribute to the high rates of head traumas [START_REF] Auvinet | Quelques aspects de la pathologie chez le cavalier, prévention 6ème journée d'étude "Quoi de neuf en matière d'etudes et de recherches sur le cheval ?[END_REF], even despite the protection equipment which is very likely safer today than any kind of equipment from the Medieval period.

The decades that followed the conquest of the Carpathian Basin, at the turn of the 9th and 10th centuries, were marked by raid expeditions and conflicts, which involved the populations who settled there. This is attested, for instance, by the presence of weapons in the cemeteries from that period, found in association with the individuals in their graves, and the presence of earthen forts, built throughout the Carpathian Basin [START_REF] Visy | Hungarian Archaeology at the Turn of the Millennium[END_REF]. Compared to individuals who were mostly urban workers living in Lisbon during the first half of the 20th century, higher rates of traumatic lesions were expected. However, the differences were not significant for almost all bones or anatomical regions, and we observed, in fact, only exceptional cases of traumas likely resulting from interpersonal violence in the Hungarian series, such as a cut wound on the skull probably inflicted by a saber (individual SH9). This could partly reflect the fact that our sample from Lisbon was composed of manual workers, relatively prone to accidental injuries (Alves [START_REF] Alves Cardoso | A portrait of gender in two 19th and 20th century Portuguese populations: a palaeopathological perspective[END_REF].

The ovalization of the acetabulum

Vertical elongation of the acetabulum or anterosuperior extension of the acetabular rim are among the most discussed skeletal changes that could be related to the practice of horse riding (see Chapter 1, II.D.1; Table 4). Unlike most of them, variations of the shape of the acetabulum can be measured, and different methods have been used to investigate this aspect. We followed the same approach as Baillif-Ducros et al. ( 2012 Finally, through direct measurements and the calculation of an index vertical/horizontal diameter of the acetabulum, which is the approach that we followed in our study, one probable Merovingian horse rider revealed very elongated acetabula compared to a reference collection [START_REF] Baillif-Ducros | Approche méthodologique pour distinguer un ensemble lésionnel fiable de la pratique cavalière. Exemple du squelette de la tombe 11 du site de « La Tuilerie » à Saint-Dizier (Haute-Marne), VIe siècle[END_REF], whereas, with the same method, [START_REF] Sarry | La sépulture multiple laténienne du site de Gondole (Le Cendre, Puy-de-Dôme)[END_REF] did not observe particularly elongated acetabula in a La Tène period mass burial associating eight horses and eight human individuals, but bone preservation was a limiting factor. This approach was also recently used in a more extensive way on Merovingian series from northeastern Gaul, including individuals with riding-related grave goods (Baillif-Ducros, 2018). The author found elongated acetabula in a notable part of these populations (with a predominance in males), including in three out of seven individuals with riding deposit in their graves. Her results, and the fact that this trait can be explained by the rider's posture, led the author to suggest that the elongation of the acetabulum, associated with other traits like Poirier's facet and hip joint changes, can represent a reliable indicator for the practice of horse riding, Beside entheseal changes, no other skeletal change presumed to be related to horse riding was this precisely investigated in the frame of methodological studies. A major limitation found in most of the previous studies focusing on this aspect is, however, that the authors were only assuming the presence of the practice of horse riding in their studied populations, without direct evidence associated with the individuals, and without comparison groups of non-riders.

Furthermore, several studies relied on the comparison between female and male individuals, which should necessarily lead to caution in the interpretations of skeletal changes in terms of activity.

Our promising results support the hypothesis that the vertical ovalization of the acetabulum may represent a potential indicator for the practice of horse riding in an archaeological population.

The shape and robusticity of lower limb bones

External bone measurements have been used to infer behaviors and activities in past populations, and are considered as reliable for testing biomechanical hypotheses (e.g., [START_REF] Larsen | Bioarchaeology: Interpreting behavior from the human skeleton[END_REF][START_REF] Capasso | Atlas of Occupational Markers on Human Remains[END_REF][START_REF] Wescott | Effect of mobility on femur midshaft external shape and robusticity[END_REF][START_REF] Campbell | Shifting patterns of limb strength among plains village horticulturalists: A critical examination of the use of cross-sectional geometry to understand cultural change[END_REF]. Although cross-sectional geometry may provide more precise information, by taking into account the internal architecture of the bone, it was demonstrated that external dimensions can also reflect the results of cross-sectional geometry and can be used with validity for testing biomechanical hypotheses [START_REF] Wescott | Effect of mobility on femur midshaft external shape and robusticity[END_REF]. These methods are, however, better suited to the study of general loading patterns than the analysis of specific activities, for which entheseal changes, for instance, are more likely to be informative [START_REF] Tichnell | Invisible Horsewomen: Horse Riding and Social Dynamics on the Steppe[END_REF].

In an exploratory approach, with the aim of evaluating general differences in activity or mobility patterns between groups, we calculated fourteen indices from direct measurements taken on the major bones of the lower limb: femur, patella, tibia, fibula, talus, and calcaneus.

These indices are general descriptors of the shape and robusticity of the lower limb bones (Table 14). The values of a majority of the indices were significantly different between groups denoting variations in the shape and robusticity of the concerned bones (Table 46). Specifically, most of the indices (ten out of fourteen) revealed significant differences between the Hungarian group without riding deposit (NRD) in the graves and the comparison group from the Lisbon collection (LIS), and six indices were also significantly different between the Hungarian group with riding deposit (RD), and the LIS group. In contrast, we observed significant differences between the two Hungarian groups, RD and NRD, for only two indices.

Our results indicate a much greater variation, in general, between the Hungarian groups and the LIS group than between each Hungarian group. At this point, we wish to remind that both Hungarian groups, RD and NRD, come from the same cemetery. These results were thus expected as the Hungarian groups and the LIS group come from two very different populations, on the geographical, chronological, and cultural level. Interpopulation variation could, therefore, partly explain these differences. It is notably acknowledged that genetics are among the factors that can influence bone shape and robusticity (e.g., [START_REF] Ruff | Long bone structural analyses and the reconstruction of past mobility: A historical review[END_REF].

Since no, or much less, interpopulation variation is expected between the RD and NRD groups, the fact that there was almost no significant difference between them is of great interest.

It indicates that the series from Sárrétudvari-Hízóföld constitute, in fact, a rather homogenous population, which is supported by the majority of the previous analyses. Differences in shape and robusticity of bones can be interpreted as indicative of variation in habitual loading, and thus activity or mobility (e.g., Knüsel, 2000b;[START_REF] Mann | Relationships between lower limb cross-sectional geometry and mobility: The case of a Neolithic sample from Italy[END_REF][START_REF] Ruff | Long bone structural analyses and the reconstruction of past mobility: A historical review[END_REF][START_REF] Stock | Lower limb biomechanics and habitual mobility among mid-Holocene populations of the Cis-Baikal[END_REF], and we can therefore assume that there were no major differences in behaviors between the two Hungarian groups. Specifically, if only the individuals from the group with riding deposit were practicing horse riding, or if they were riding in a significantly more frequent or intensive way than the individuals without deposit, we would expect to observe more variations in shape and robusticity of the lower limb bones between these two groups. Thus, our results tend, once again, to suggest that the individuals without riding deposit were practicing horse riding on a similar basis as the individuals with riding deposit in their graves.

Another possible explanation for the little variation observed between both Hungarian groups could be, however, that the selected indices of shape and robusticity do not reflect the influence of the practice of horse riding on the skeleton or that horse riding has no influence on bone morphology.

As far as we know, studies establishing a relationship between shape and robusticity of lower limb bones and the practice of horse riding are very scarce and relied sometimes rather on cross-sectional geometry than external measurements. [START_REF] Ruff | Biomechanical anlaysis of northern and southern Plains femora[END_REF] compared Pre-and Posthorse Arikara populations and observed a slight trend towards femoral midshaft circularity that could be related to the use of horses, but that was not significant. The author also predicted that increased practice of horse riding might lead to increased mediolateral bending stress, and therefore to a decline in the anteroposterior-mediolateral diameter index (pilastric, at midhshaft). This aspect was observed, later on, by [START_REF] Wescott | Structural variation in the humerus and femur in the American Great Plains and adjacent regions: Differences in subsistence strategy and physical terrain[END_REF] in other equestrian nomadic populations (Sioux, Crow, Cheyenne, etc.). They showed significantly more robust long bones at the femoral midshaft and subtrochanter, and a slightly more circular femoral midshaft, compared to other hunter-gatherer and horticulturalist populations. Later on, the author gave, however, a more nuanced picture, claiming that there were only few significant differences between equestrian hunter-gatherers and other populations, and that the observed differences could result from activity, diet, genetics, or other factors [START_REF] Wescott | Biomechanical Analysis of Humeral and Femoral Structural Variation in the Great Plains[END_REF]. More recently, in two populations from Post-Contact period villages from the Great Plains, Campbell (2018) observed a reduction of bone strength variables in males, and attributed this to a reduction in mobility notably related to the introduction of the horse. By using horses for transportation, less stress is indeed expected on the lower limb, therefore leading to less bending and compression [START_REF] Campbell | Shifting patterns of limb strength among plains village horticulturalists: A critical examination of the use of cross-sectional geometry to understand cultural change[END_REF].

The indices that we used in our study were selected in an exploratory way as indicators to observe general differences in activity or mobility level between groups. In spite of this, if we attempt to focus more specifically on the index values, we observe significant differences regarding the shape of midshaft and subtrochanter of the femur: the indices (FEM I2 and FEM I3, respectively) were significantly higher in the LIS group compared to each Hungarian group. This indicates that the femoral diaphyses in the Hungarian groups tended to be wider in the mediolateral plane (or less elongated in the anteroposterior plane) compared to the LIS group. FEM I2 values were also closer to the value of 100 in the Hungarian groups compared to the LIS group, which indicates that diaphyses were more circular at midshaft in the Hungarian groups. This reminds the observations made by [START_REF] Ruff | Biomechanical anlaysis of northern and southern Plains femora[END_REF] and [START_REF] Wescott | Structural variation in the humerus and femur in the American Great Plains and adjacent regions: Differences in subsistence strategy and physical terrain[END_REF] concerning mediolateral bending stress and the circularity of femoral diaphyses (see above).

Circular femoral diaphyses, in particular, have been, in fact, linked to a decrease in mobility [START_REF] Capasso | Atlas of Occupational Markers on Human Remains[END_REF][START_REF] Stock | Lower limb biomechanics and habitual mobility among mid-Holocene populations of the Cis-Baikal[END_REF]. We could therefore assume from these results that the Hungarian groups were less bipedally mobile (i.e., walking or running), which could be explained by the daily practice of horse riding. This is supported by the fact that the populations from the Conquest period were semi-nomadic societies, where horses played an important role in daily life.

The assumption that the Hungarian groups were less bipedally mobile because of their use of horses can, however, be contradicted by other index values. We observed, indeed, a significant difference in the robusticity of femurs (FEM I1) when both sides were combined.

Pairwise comparisons did not succeed to reveal between which groups were found these significant differences, but we observed that the femurs were more robust in the Hungarian groups compared to the LIS group. In addition, low pilastric (FEM I2) and platymeric (FEM I3) index values have been linked to more mechanically stressed bones [START_REF] Larsen | Bioarchaeology: Interpreting behavior from the human skeleton[END_REF], which would thus be the case in the Hungarian groups compared to the LIS group. Finally, the platycnemic index values (TIB I2), which described the shape of the shaft of the tibia, also showed inconsistent results, as the values were higher in the NRD group, and lower in the RD and LIS groups. This index was even one of only two that showed a significant difference between both Hungarian groups. As the measurements involved in the calculation of this index are not taken at a fixed point but at the nutrient foramen, which location is variable, some have, however, questioned its reliability and value [START_REF] Andermann | The cnemic index: A critique[END_REF][START_REF] Ponce | A comparative study of activity-related skeletal changes in 3rd-2nd millennium BC coastal fishers and 1st millenium AD inland agriculturists in Chile, South America[END_REF].

As far as we know, there are only very few studies, beside ours, that analyzed indices of shape and robusticity of the lower limb on a sample of individuals associated with horse remains or riding deposit in their graves. In the medieval necropolis of Vicenne (Italy), Belcastro and Facchini (2001) compared thirteen "horsemen" with the rest of the individuals with the aim of identifying possible interpopulation variations. Among other things, the main indices of shape and robusticity of the lower limb were calculated. The authors did not observe significant differences between the samples and did not comment further those results. It is however interesting to highlight that the group of "horsemen", although of a very limited sample size, also presented lower values for the femoral pilastric and platymeric indices compared to the other male individuals, in the same way as for our Hungarian groups compared to the Lisbon group. In addition, when [START_REF] Blondiaux | Essai d'anthropologie physique et de paléopathologie des populations du nord de la Gaule au haut Moyen Age[END_REF][START_REF] Blondiaux | À propos de la dame d'Hochfelden et de la pratique cavalière : discussion autour des sites fonctionnels fémoraux[END_REF] analyzed different northern French series from the High and Late Middle Ages, he observed that the only series showing clear platymeric femurs (i.e., with low platymeric index values) was the one from a High Medieval cemetery in which were found horse burials [START_REF] Blondiaux | Essai d'anthropologie physique et de paléopathologie des populations du nord de la Gaule au haut Moyen Age[END_REF][START_REF] Blondiaux | À propos de la dame d'Hochfelden et de la pratique cavalière : discussion autour des sites fonctionnels fémoraux[END_REF].

In the end, the mixed results of our analysis make it difficult to determine if the Hungarian groups were more or less mobile than the group from Lisbon. A factor that should also be considered is that, although the semi-nomadic populations from the Conquest period were riding horses, it is difficult to evaluate it the use of stirrups and the practice of mounted archery, which requires very strong stabilization, may have had an effect on bone shape and robusticity. [START_REF] Wescott | Biomechanical Analysis of Humeral and Femoral Structural Variation in the Great Plains[END_REF] claimed, referring specifically to the studies on the Plains, that biomechanical studies of long bones have raised more questions than they have answered. With this exploratory analysis, we highlighted how little is known about the influence of the practice of horse riding on bone shape and robusticity, and how this very complex question will require further investigation. A better selection of variables, less exploratory, and more enlightened regarding biomechanical aspects, could already represent a promising further step.

The identification of reliable horse riding-related skeletal changes

Finally, many statistically significant differences were revealed from our analyses of different types of skeletal changes and comparisons between two groups of individuals from the same archaeological Hungarian collection, those with (RD) and without riding deposit (NRD) in their graves, and a group of presumed non-riders from the modern documented collection from Lisbon (LIS).

On the one hand, most of the analyses showed no significant difference between both Hungarian groups. This was the case for the entheseal changes, joint changes, and Schmorl's nodes, and for a majority of the morphological variants of the femur and indices of shape and robusticity.

On the other hand, all types of analyses and a majority of the investigated skeletal changes indicated significant differences between either the Hungarian group with riding deposit and the Lisbon group, either between the Hungarian group without riding deposit and the Lisbon group, or between both Hungarian groups and the Lisbon group.

A majority of the skeletal changes involved in this study have a multifactorial etiology, which includes genetic factors. Interpopulation could therefore explain, at least partly, the similarity observed between both Hungarian groups and the differences with the Lisbon group.

However, all types of analyses and almost all skeletal changes included here were selected because they are commonly used as general or specific indicators of activity or mobility in past populations. It was indeed demonstrated that they are, to a certain extent, influenced by mechanical factors (e.g., Knüsel, 2000b;[START_REF] Jurmain | Bioarchaeology's Holy Grail: The Reconstruction of Activity[END_REF][START_REF] Schrader | Activity, Diet and Social Practice. Addressing Everyday Life in Human Skeletal Remains[END_REF]. Since interpopulation variation alone cannot explain the differences observed between groups and considering the fact that we applied strict methodological criteria to limit the influence of other factors (e.g., sex, age, pathological conditions), we can assume that our results reflect some differences in behavior and activity between groups.

The populations from the Hungarian Conquest period were semi-nomadic societies, in which horses took an essential role. The presence of equipment related to horse riding (stirrups, girth buckles, bits) or horse bones associated with the individuals in the graves strongly suggests that the concerned individuals were riding during their life, and it confirms, in general, the presence of horse riders in the population.

Only the analysis of comparative samples of known performers and non-performers can allow distinguishing skeletal markers that are specific to an activity [START_REF] Tichnell | Invisible Horsewomen: Horse Riding and Social Dynamics on the Steppe[END_REF]. The modern documented collection from Lisbon was chosen as a comparison group because we could assume that the individuals were not practicing horse riding, or at least not in a regular and intensive way (see Chapter 2, II.C.1). In addition, the occupation of each individual was known, which allowed selecting only physically "active" workers, whose skeletal remains were prone to show some activity-related skeletal changes. A comparison between the semi-nomadic individuals from the Hungarian Conquest period and modern urban dwellers with only low level of physical activity (i.e., office workers, students) would have been, indeed, of very limited interest.

Taking into account all those considerations, it is only reasonable to suggest that the main difference in behavior or activity between the Hungarian groups and the Lisbon group was the practice of horse riding. A great majority of the skeletal changes that showed significantly higher rates or values in the Hungarian groups compared to the Lisbon group can, in fact, be explained by anatomical and functional aspects involved in the practice of horse riding. In addition, their association with this activity was previously mentioned in the anthropological literature, including sometimes on other presumed riding populations.

In the end, our results allowed identifying several promising skeletal changes for which the relationship with the practice of horse riding is probable: We must highlight that, although these skeletal changes may indeed be influenced by the practice of horse riding, they should not be considered as a set of skeletal changes that are specific for this activity. This way, the presence of some or all of these skeletal changes in particular individuals cannot be considered as evidence that they were riders during their life, but it can naturally lead bioarchaeologists and paleopathologists to regard them as potential riders.


The presence of several of these skeletal changes together can, however, contribute to identify, statistically, the practice of horse riding in a group or population. Specifically, the most adequate research approach that we recommend would be to compare the frequencies and values of those skeletal changes observed in a group of interest with populations of confirmed -or, failing that, presumed -riders and non-riders, to evaluate the possibility that horse riding was a prevailing activity in this group. In this respect, we believe that our results can represent pertinent comparative data for future research, considering the nature of the collections that we studied and the scoring methods that we used.

Following this approach, we also note that higher frequencies of fractures observed on the bones of the upper limb, and notably at the clavicle, compared to other anatomical regions, can represent a complementary indication, in addition to some of the skeletal changes previously mentioned.

The interest of researchers on horse riding-related skeletal changes followed the influential contributions of Miller and collaborators [START_REF] Miller | The Effect of Horseback Riding on the Omaha and Ponca: Paleopathological Indications of European Contact[END_REF][START_REF] Miller | The Effect of Horseback Riding on the Human Skeleton[END_REF][START_REF] Reinhard | Trade, contact, and female health in Northeast Nebraska[END_REF], and Pálfi and Dutour [START_REF] Pálfi | Traces des activités sur les squelettes des anciens Hongrois[END_REF][START_REF] Pálfi | Activity-induced skeletal markers in historical anthropological material[END_REF][START_REF] Pálfi | Maladies dans l'Antiquité et au Moyen-Âge. Paléopathologie comparée des anciens Gallo-Romains et Hongrois[END_REF], who, especially, identified the signs of a "Horse Riding Syndrome" in several individuals from the collection of Sárrétudvari-Hízóföld. This doctoral research relied on a reexamination of this series in the frame of a systematic and comparative methodological investigation of different types of skeletal changes. Our results allowed evaluating the reliability of these changes as possible indicators for the practice of horse riding, and notably confirmed the promising value of several of the traits that had originally been mentioned: the entheseal changes at the adductor tubercle and linea aspera of the femur, and at the ischial tuberosity of the coxal bone, as well as the extension of the articular surface of the femoral head onto the neck and the superior extension of the acetabulum.

The horse riders from the Hungarian Conquest period

As mentioned previously, this study relied on the comparison between two groups of individuals from the series from the Hungarian Conquest period cemetery of Sárrétudvari-Hízóföld. The distinction between the two groups of individuals was based only on one criterion, the presence or absence of any equipment related to horse riding or horse bones (or both) in their graves. The working hypothesis was that the individuals from the group with riding deposit, at least, was regularly practicing horse riding during their life and would, therefore, show skeletal changes related to this activity. Through multiple comparisons between the two Hungarian groups and an out-sample group of non-riders, we observed that the Hungarian groups showed higher rates for different skeletal changes that can be related to the practice of horse riding according to anatomical and functional aspects. Our interpretations were supported by previous observations from the anthropological literature and by sports medicine data. There was, however, no significant difference between both Hungarian groups with or without riding deposit for a large majority of the analyses that we performed. If only the individuals with riding deposit in their graves were practicing horse riding, we would expect to observe more differences for all skeletal changes between them and the group of individuals without riding deposit, and notably in the analyses of entheseal changes and Schmorl's nodes, and in the metric analyses. This led us to suggest that the individuals without riding deposit in their graves were likely practicing horse riding as well.

On the large amount of skeletal changes that were tested, significant differences between both Hungarian groups were in fact observed only for Poirier's facet, the index of ovalization of the acetabulum (with a borderline significant p value of .050), and for two indices calculated from measurements on the lower limb bones (which concerned the tibia and talus). Although it is not impossible that these observations might reflect differences in the intensity or regularity of the practice of horse riding, we consider that they are not enough to claim that only the individuals with riding deposit were riders, compared to the numerous skeletal changes that revealed no difference between both Hungarian groups. Those were all the entheseal changes that we investigated, as well as all joint changes, five out of six morphological variants of the femur, Schmorl's nodes at all vertebral levels, and twelve out of fourteen indices of shape and robusticity.

The populations from the Hungarian Conquest period were unanimously described by other cultures (e.g., Muslims, Byzantines, Western Christians) as nomadic horse riders. Around 900, the abbot Regino of Prüm wrote that "they spend all their time on horseback; they travel, rest, think, and talk on their horses" (Engel, 2001: 15). Descriptions made by the Byzantine Emperor

Leo VI also mention that the Hungarians grew up on horseback and that they were unable to fight on foot. Horses were essential during campaigns, for warfare but also as a source of food and milk, and they were very numerous [START_REF] Róna-Tas | Hungarians and Europe in the early Middle Ages: An introduction to early Hungarian history[END_REF][START_REF] Engel | The Realm of St Stephen. A History of Medieval Hungary[END_REF]. Furthermore, the importance of the horse for these populations is documented by archaeological evidence found in the cemeteries, such as symbolic horse burials, equipment related to riding, sometimes including lavishly ornated harnesses or stirrups, or also widespread artistic depictions of horse figures on braid ornaments [START_REF] Visy | Hungarian Archaeology at the Turn of the Millennium[END_REF]. Bearing this in mind, the idea that the practice of horse riding was prevailing in the population (or at least in the male population) is reasonable.

The presence or absence of archaeological grave goods may raise different hypotheses regarding funerary practices [START_REF] Härke | The nature of burial data[END_REF]. In light of our results, the possibility that riding deposits may have concerned only actual riders in the population is rather unlikely. Instead, the distinction between individuals who were associated or not with riding deposit and horse bones may have rather been based on various social, religious, or symbolic aspects (e.g., recognition of a certain status, rank, or military skills). This is supported by the fact that graves with horse riding-related deposit are relatively rare in the Carpathian Basin, representing approximately 10% of around 30 000 known graves [START_REF] Vörös | Adatok a honfoglalás kori lovastemetkezésekhez[END_REF]. In that respect, the anthropological data contribute to clarify the differences observed between the historical and archaeological sources.

We must finally also consider a more pragmatic reason for the differences in archaeological goods between the individuals: the elements originally deposited in the graves may simply not have been preserved due to various factors (e.g., taphonomic processes, disappearance of organic materials, and lootings). Thus, it must be acknowledged that some individuals without deposit in their graves may have initially received a deposit. If the presence of riding equipment or horse bones in the graves concerned only horse riders, this could have contributed to mitigating significant differences between both Hungarian groups. Although numerous studies mentioned skeletal changes as possible indicators for horse riding, most of them failed to meet several of the essential criteria presented above. Specifically, the main limits that we identified in the literature were the fact that the practice of horse riding was often only assumed without any direct evidence or the lack of a comparison sample and the lack of consideration of some methodological confounding factors. We should however underline that, beside the early contributions that initiated the interest on this topic in the 1990's [START_REF] Miller | The Effect of Horseback Riding on the Omaha and Ponca: Paleopathological Indications of European Contact[END_REF][START_REF] Miller | The Effect of Horseback Riding on the Human Skeleton[END_REF]Pálfi et al., 1992a;[START_REF] Reinhard | Trade, contact, and female health in Northeast Nebraska[END_REF][START_REF] Pálfi | Activity-induced skeletal markers in historical anthropological material[END_REF][START_REF] Pálfi | Maladies dans l'Antiquité et au Moyen-Âge. Paléopathologie comparée des anciens Gallo-Romains et Hongrois[END_REF], the methodological studies led by Belcastro and collaborators (Belcastro & Facchini, 2001;Belcastro et al., 2001;[START_REF] Belcastro | Continuity or discontinuity of the life-style in central Italy during the Roman imperial age-early middle ages transition: Diet, health, and behavior[END_REF], Djukic and collaborators (2016;[START_REF] Djukic | Morphological appearance of muscle attachment sites on lower limbs: Horse riders versus agricultural population[END_REF][START_REF] Baillif-Ducros | La pratique de la monte à cheval au haut Moyen Âge (fin Ve-VIIe siècle) dans le nord-est de la Gaule. État des connaissances archéologiques[END_REF]collaborators (Baillif-Ducros et al., 2012;[START_REF] Baillif-Ducros | La pratique de la monte à cheval au haut Moyen Âge (fin Ve-VIIe siècle) dans le nord-est de la Gaule. État des connaissances archéologiques[END_REF] particularly stand out among the rest of the anthropological literature on the topic.

Main contributions, limitations, and perspectives

On another note, we must remind that research on activity-related skeletal changes is characterized by many pitfalls (e.g., [START_REF] Dutour | Activités physiques et squelette humain : le difficile passage de l'actuel au fossile[END_REF][START_REF] Jurmain | Bioarchaeology's Holy Grail: The Reconstruction of Activity[END_REF][START_REF] Schrader | Activity, Diet and Social Practice. Addressing Everyday Life in Human Skeletal Remains[END_REF], and that, despite our efforts, this study showed also some limitations. Although several of them are specific to each type of analysis and were already addressed in the relevant parts of this discussion chapter (see above I to VII), we can mention here some of the main issues that we have been dealing with.

The first and main challenge that we faced was the multifactorial etiology of most (if not all) of the skeletal changes that are used as activity-related indicators (see Chapter 1, I.C).

Acknowledging this problem led us to include in this doctoral research only a small part of the individuals from the Hungarian series, i.e., 67 out of a total of 265 individuals that were uncovered from the 262 graves of the cemetery. The strict methodological criteria that we applied allowed limiting the influence of some confounding factors: we selected only adult individuals to limit the influence of growth and developmental changes; we focused on males to eliminate the influence of sexual dimorphism; we distinguished the young and mature adults in the analyses of entheseal and joint changes to limit the effect of aging; we excluded pathological cases (e.g., DISH, traumas, dysplasia) that could influence the development of the investigated changes. Despite genetics, body size and weight are also among the other possible factors that can influence some of the investigated skeletal changes. These are factors that can be controlled, with more or less reliable estimations based on equations, or inferred directly from bone measurements (e.g., [START_REF] Ruff | Stature and body mass estimation from skeletal remains in the European Holocene[END_REF]. Including these aspects in our study would have, however, limited too much the sample sizes and, thus, diminished the reliability and quality of the statistical analyses.

This leads to the second major challenge that we faced, and that is closely related: the rather limited sample sizes. This problem considerably limited our analyses and led us to interpret some of the results with caution. It concerned especially the group from the archaeological series with riding deposit. Even if this sample of 17 individuals represents, as mentioned above, the largest of its kind, it is still not a large size for conducting analyses, especially if we consider the fact that bone preservation and the exclusion of some data in certain analyses (e.g., old adults, pathological cases, unpaired bones in asymmetry analyses) contributed to decreasing the number of possible observations in this sample. This issue was also the main reason why we performed two series of analyses in the case of entheseal and joint changes, one on young and mature adult individuals only, and one, of a larger sample size, on all adult individuals, regardless of the age category.

Future attempts to address the different limitations mentioned above represent our main perspectives. The main one will be to collect more data from other series from the Hungarian Conquest period that also include direct archeological evidence for the practice of horse riding by individuals, such as the rich cemeteries of Karos, in northeastern Hungary (Révész, 1996b[START_REF] Révész | The cemeteries of the Conquest period[END_REF]. Larger sample sizes in the archaeological groups will allow us performing more reliable and powerful analyses, including multivariate analyses, which we chose not to perform at this stage as they generally require large sample sizes and few missing data. With more data and larger samples, we should also be able to control for additional confounding factors such as body size and weight. In addition, the sex of several adult individuals in the Hungarian series could not successfully be determined, mostly due to occasionally poor bone preservation.

Performing a secondary sexual diagnosis, based on discriminant functions elaborated with postcranial measurements that are dimorphic within the population, will allow including more individuals in the analyses [START_REF] Murail | A new approach to sexual diagnosis in past populations. Practical adjustments from Van Vark's procedure[END_REF][START_REF] Thomas | Identités funéraires, variants biologiques et facteurs chronologiques : une nouvelle perception du contexte culturel et social du Cerny (Bassin parisien[END_REF].

This leads to another important perspective that is the investigation of the activity-related skeletal changes in female samples. We expect that it will provide valuable insights into the possible participation of women in warfare, as well as the organization of the societies of the Hungarian Conquest period and the significance of some funerary practices. We notably remind that, in the cemetery of Sárrétudvari-Hízóföld, at least one of the 32 graves with riding deposit concerned a female adult individual. Genetic analyses might also help to determine the sex of the subadult individuals with riding deposit in their graves, which would also significantly contribute to improving our understanding of these societies.

Furthermore, the question of the riding style will be another point of interest as we ignore so far if the steppe nomad style of the populations from the Hungarian Conquest period (Uray- [START_REF] Uray-Kőhalmi | A steppék nomádja lóháton, fegyverben[END_REF] and other riding styles may result in similar bone modifications. Different styles may indeed involve different movements, and thus different muscular action [START_REF] Djukic | Morphological appearance of muscle attachment sites on lower limbs: Horse riders versus agricultural population[END_REF]. This analysis focused only on one semi-nomadic population. There is therefore a possibility that our interpretations regarding the association between the skeletal changes and the practice of horse riding may be valid only in the case of this population. Only a few authors mention this aspect [START_REF] Eng | Morphometric analysis of acetabular rim shape among ancient Mongolian pastoralists[END_REF][START_REF] Tichnell | Invisible Horsewomen: Horse Riding and Social Dynamics on the Steppe[END_REF][START_REF] Eng | A bioarchaeological study of osteoarthritis among populations of northern China and Mongolia during the Bronze Age to Iron Age transition to nomadic pastoralism[END_REF][START_REF] Baillif-Ducros | La pratique de la monte à cheval au haut Moyen Âge (fin Ve-VIIe siècle) dans le nord-est de la Gaule. État des connaissances archéologiques[END_REF]) (see Chapter 1, II.D.2.c), and the only study that addresses this question suggests that there may indeed not be a universal suite of features related to horse riding [START_REF] Tichnell | Invisible Horsewomen: Horse Riding and Social Dynamics on the Steppe[END_REF]. Baillif-Ducros (2018) also suggests that horse riding indicators may be specific to a chronological period. A future comparative analysis including other nomadic and semi-nomadic populations (e.g., Early-and Middle Avars, Mongols, Post-Contact Native Americans) should allow us to identify the possible existence of specific or common features according to the riding style. In that regard, a more detailed analysis of the upper body (entheseal and joint changes of the upper limbs, in particular) may contribute not only to extend our analyses and to identify possible additional skeletal changes related to horse riding, but also to give insights into this riding style question.

Some valuable information might also be provided by individuals who, nowadays, perform reconstructions of mounted archery, with the attempt to be as close as possible to the historical techniques used in various periods and cultures. Certain people became specialists in this activity and have been performing such reconstructions for decades, following an approach that could be considered, to some extent, as experimental ethnoarchaeology. This is the case, for instance, of the team from the Ópusztaszer National Heritage Park, in Hungary, whom we had the opportunity to visit during this doctoral research (Figure 39). This notably helped to visualize and understand better the actual movements involved in mounted archery in the style of the populations who conquered the Carpathian Basin. Future collaborations with experimenters would be of great interest to provide more information regarding the influence of horse riding, and mounted archery, in particular, on the skeleton and the body. While entheses and their changes have been extensively studied with clinical, radiological, histological and osteological methods at macroscopic and microscopic scales (e.g., [START_REF] Cooper | Tendon and ligament insertion. A light and electron microscopic study[END_REF][START_REF] Resnick | Entheses and enthesopathy. Anatomical, pathological, and radiological correlation[END_REF][START_REF] Olivieri | Enthesiopathy: clinical manifestations, imaging and treatment[END_REF][START_REF] Benjamin | The skeletal attachment of tendons-tendon 'entheses[END_REF][START_REF] Claudepierre | The entheses: histology, pathology, and pathophysiology[END_REF][START_REF] Maffulli | Tendon Injuries[END_REF][START_REF] Villotte | Enthésopathies et activités des hommes préhistoriques : recherche méthodologique et application aux fossiles européens du Paléolithique supérieur et du Mésolithique[END_REF][START_REF] Junno | Cross sectional properties of the human radial tuberosity[END_REF][START_REF] Schlecht | Understanding entheses: Bridging the gap between clinical and anthropological perspectives[END_REF]Henderson, 2013a;Henderson et al., 2016;[START_REF] Miszkiewicz | Ancient Human Bone Microstructure in Medieval England: Comparisons between Two Socio-Economic Groups[END_REF], the 3D approach has also begun to be used as a tool for studying EC, but these researches focus mostly on entheseal surfaces [START_REF] Pany | The scientific value of using a 3D surface scanner to quantify entheses[END_REF]Henderson, 2013b;[START_REF] Noldner | 3D representation and analysis of enthesis morphology[END_REF][START_REF] Nolte | Three-dimensional surface area of the distal biceps enthesis, relationship to body size, sex, age and secular changes in a 20th century American sample[END_REF][START_REF] Karakostis | Morphometric patterns among the 3D surface areas of human hand entheses[END_REF]. In the frame of our methodological investigation on the activities of the populations from the Hungarian Conquest period, we attempted to address the question of the cause of the EC through an exploratory and experimental approach with the complementary use of microtomodensitometry (µ-CT) and 3D imaging, which has been little applied to occupational markers so far [START_REF] Djukic | Bone microarchitecture at muscle attachment sites: The relationship between macroscopic scores of entheses and their cortical and trabecular microstructural design[END_REF][START_REF] Djukic | Bone macromorphology at muscle attachment sites: Its relationship with the microarchitecture of the underlying bone and possible implications for the reconstruction of habitual physical activities of past populations[END_REF][START_REF] Mulder | Comparing Microarchitecture with Macromorphology: Is entheseal change a marker of activity? Paper presented at the "Working your fingers to the bone[END_REF]. In their study, [START_REF] Djukic | Bone microarchitecture at muscle attachment sites: The relationship between macroscopic scores of entheses and their cortical and trabecular microstructural design[END_REF] used µ-CT for performing metric analyses of bone microarchitecture on several lower limb entheses, to study the relationship between macro-and microstructure, as well as between cortical and trabecular parameters at the entheseal level.

They showed a lack of correlation between the stages of a macroscopic scoring system and the microstructural features at the entheses.

While we did not have the intention to elaborate a complete methodology and to base our final interpretations on the preliminary results obtained from this investigation, we expected to lay the foundation for further studies on that aspect. The particular relevance of our study materials, a population from the Hungarian Conquest period, whose activities are historically and archaeologically well-documented, was a major motivation to initiate this investigation.

The aim was to determine if it could be possible, in the long run, to reliably distinguish an enthesis modified by mechanical factors from an enthesis altered by degenerative or pathological processes.

The selection of the enthesis

We decided to focus for this part on the upper limb, and thus, on archery, the other main activity that is acknowledged for the populations from the Hungarian Conquest period. The main criterion that led us to proceed in this direction was the enthesis to study. We determined that the bicipital tuberosity of the radius would be particularly pertinent for this investigation.

The tuberositas radii, which is the insertion site of biceps brachii, is one of the fibrocartilaginous entheses [START_REF] Benjamin | The histology of tendon attachments to bone in man[END_REF]. These are the most documented and relevant group of entheses (the other group being the fibrous entheses) in the attempt to reconstruct past activities [START_REF] Havelková | Enthesopathies: Test of reproducibility of the new scoring system based on current medical data[END_REF][START_REF] Villotte | Enthésopathies et activités des hommes préhistoriques : recherche méthodologique et application aux fossiles européens du Paléolithique supérieur et du Mésolithique[END_REF][START_REF] Villotte | Enthesopathies as occupational stress markers: Evidence from the upper limb[END_REF]Henderson et al., 2013;[START_REF] Villotte | Understanding entheseal changes: Definition and life course changes[END_REF][START_REF] Thomas | Bioarchaeology of the middle Neolithic: Evidence for archery among early European farmers[END_REF][START_REF] Weiss | Examining Activity Patterns and Biological Confounding Factors: Differences between Fibrocartilaginous and Fibrous Musculoskeletal Stress Markers[END_REF]Henderson et al., 2017b). Biceps brachii is one of the flexor and supinator muscles of the elbow, and changes at tuberositas radii were previously interpreted to be linked with occupation [START_REF] Dutour | Enthesopathies (lesions of muscular insertions) as indicators of the activities of Neolithic Saharan populations[END_REF][START_REF] Hawkey | Activity-induced musculoskeletal stress markers (MSM) and subsistence strategy changes among ancient Hudson Bay Eskimos[END_REF][START_REF] Pálfi | Maladies dans l'Antiquité et au Moyen-Âge. Paléopathologie comparée des anciens Gallo-Romains et Hongrois[END_REF][START_REF] Robb | The interpretation of skeletal muscle sites: a statistical approach[END_REF][START_REF] Molnar | Tracing prehistoric activities: Musculoskeletal stress marker analysis of a stone-age population on the Island of Gotland in the Baltic sea[END_REF][START_REF] Weiss | Muscle markers revisited: Activity pattern reconstruction with controls in a central California Amerind population[END_REF][START_REF] Baker | Marqueurs osseux d'activités physiques : étude du squelette appendiculaire d'une population nabatéo-romaine (Syrie du Sud)[END_REF][START_REF] Thomas | Bioarchaeology of the middle Neolithic: Evidence for archery among early European farmers[END_REF][START_REF] Tihanyi | Investigation of Hungarian Conquest Period (10th c. AD) archery on the basis of activity-induced stress markers on the skeleton -preliminary results[END_REF]. Agricultural and building activities, especially carrying heavy loads, have proved to be a potential cause for EC at this enthesis [START_REF] Commandré | Pathologie abarticulaire[END_REF][START_REF] Galera | Enthesopathies in a Spanish medieval population: anthropological, epidemiological, and ethnohistorical aspects[END_REF][START_REF] Al-Oumaoui | Markers of activity patterns in some populations of the Iberian Peninsula[END_REF][START_REF] Havelková | Enthesopathies and activity patterns in the Early Medieval Great Moravian population: Evidence of division of labour[END_REF][START_REF] Rojas-Sepúlveda | Enfermedad articular degenerativa y cambios entesiales en seis colecciones óseas prehispánicas del noroccidente de América del Sur[END_REF] Finally, another motivation for the choice of the radial tuberosity for this part was more practical. This fibrocartilaginous enthesis has quite well-defined margins, which is a particularly determinant criterion in order to perform the micro-computed tomography (µ-CT) acquisition and the 3D reconstruction of the regions of interest.

Materials

For this exploratory research, the methodology of the analysis of the microstructure of the bicipital tuberosity had already been elaborated and tested on two adult individuals from Hassiel-Abiod (northern Mali), belonging to a Neolithic population of hunters-fishermen-gatherers who lived close to lake or wetland areas about 7 000 BP. This material had been studied by Dutour in the first place, and EC observed at the bicipital tuberosity of the radius contributed to the hypothesis of the practice of archery [START_REF] Dutour | Enthesopathies (lesions of muscular insertions) as indicators of the activities of Neolithic Saharan populations[END_REF][START_REF] Dutour | Hommes fossiles du Sahara : peuplements holocènes du Mali septentrional[END_REF]. This preliminary exploration consisted in the comparison between an enthesis with EC and a normal, regular, and smooth enthesis, in order to observe a possible difference in their microstructure (Berthon et al., 2015a).

The promising results led us to go further and apply this methodology on our materials of early Hungarians from the Conquest period to investigate if the repeated movement involved in archery could result in differences in the entheseal microstructure compared to the normal and pathological aspect of the enthesis (Berthon et al., 2016a).

To that end, we relied on three pairs of radii, belonging to three adult males (Figure 40). total of 230 burials were excavated and studied [START_REF] Beurion | Rapport de diagnostic. Val-de-Reuil[END_REF]Berthon et al., 2015b). No evidence for warfare context had been uncovered. The examination of the skeletal remains of the selected individual (VDR4114), a 20-50 years old male, did not suggest any particular pathological condition or stress prone to lead to bias in the analysis of entheseal changes. Both radial tuberosities showed smooth-rounded contour and smooth and regular surface, despite slight taphonomic alterations likely due to roots in the soil.

2) The second individual is presumed to show activity-related EC at bicipital tuberosities.

This mature male comes from the main collection of this doctoral research, the Hungarian Conquest period cemetery of Sárrétudvari-Hízóföld. The selected individual (SH179) was buried with arrowheads and bow elements discovered in association with the skeleton [START_REF] Nepper | Hajdú-Bihar megye 10-11. századi sírleletei I-II. (Magyarország honfoglalás és kora Árpád-kori sírleletei 3)[END_REF]. The two radii of this "presumed archer" exhibited raised margins, bone formation, macro-porosity, and fine porosity as well as erosive areas at bicipital tuberosities.

3) The third and last individual has been selected to represent EC probably related to a metabolic condition. This mature male comes from the Hungarian Late Middle Ages -Early Modern times cemetery (16-17th centuries) of Bácsalmás-Homokbánya. This cemetery was excavated in several phases between 1993 and 2003, by Erika Wicker, Zoltán Polgár and László

Pintér, and 481 skeletons were unearthed. The archaeological and historical data suggest the presence of a population of farmers, with no evidence for warfare context [START_REF] Lovász | Skeletal manifestations of infantile scurvy in a late medieval anthropological series from Hungary[END_REF].

The selected individual (BACS173) was affected by diffuse idiopathic skeletal hyperostosis (DISH) or Forestier's disease. This metabolic disorder is particularly characterized by the calcification and ossification of soft tissues, including ligaments and entheses [START_REF] Resnick | Radiographic and pathologic features of spinal involvement in diffuse idiopathic skeletal hyperostosis (DISH)[END_REF][START_REF] Waldron | Palaeopathology[END_REF][START_REF] Holgate | Diffuse idiopathic skeletal hyperostosis: Diagnostic, clinical, and paleopathological considerations[END_REF]. The main diagnostic criteria that were observed on the skeleton for this metabolic disorder are: ossification of the right side anterior longitudinal ligament from T2 to L5 (complete and non-complete fusion), with a "candle wax" appearance; normal intervertebral disc spaces; entheseal changes at radii, claviculae, patellae, calcanei, or ilii; ossification of rib cartilage and sternocostal ligaments [START_REF] Paja | Diffuse idiopathic skeletal hyperostosis -appearance and diagnostics in Hungarian osteoarcheological materials[END_REF][START_REF] Paja | Joint fusions in paleopathology: Diagnosis and epidemiology[END_REF]. The bicipital tuberosities, in particular, were characterized by raised and irregular margins, bone formation, irregular surface, and macroporosity.

Methodology

All 6 radii were µ-CT scanned in order to investigate bone microarchitecture of the entheses. Microtomodensitometry provides, in a nondestructive way, an insight into the biomechanical properties of bone and the characteristics of bone remodeling through a threedimensional approach (e.g., [START_REF] Lespesailles | Imagerie de la microarchitecture osseuse[END_REF]Coqueugniot et al., 2010a;[START_REF] Colombo | La micro-architecture de l'os trabéculaire en croissance : variabilité tridimensionnelle normale et pathologique analysée par microtomodensitométrie[END_REF][START_REF] Rittemard | Analyse macro-et micro-morphologique de l'os cortical en croissance : physiologie versus pathologie du périoste[END_REF][START_REF] Khoury | The use of nano-computed tomography to enhance musculoskeletal research[END_REF]. We applied the µ-CT acquisitions processing chain [START_REF] Coqueugniot | Procédé de modélisation d'une pièce formée de tissu osseux[END_REF] Maximum Height) 3D algorithm, allowing the software to automatically identify the optimal limits between each material such as bone and air [START_REF] Spoor | Linear measurements of cortical bone and dental enamel by computed tomography: applications and problems[END_REF][START_REF] Dutailly | 3D surface reconstruction using HMH algorithm[END_REF]. The radii were CT scanned at PLACAMAT (UMS 3626, CNRS/University of Bordeaux), Pessac, France, on a GE® Phoenix v|tome|x s, with an isotropic resolution between 15.7 and 17.8 µm.

We focused the acquisitions on the enthesis area. The micro-CT was operated at 120 kV and 110 µA, with a 500 ms integration time per projection. The data, which are slices in the three orientations of space, were then treated with TIVMI® software to obtain 3D reconstructions from slices superposition.

Several preliminary steps were required in order to analyze the microarchitecture of the entheses. We realized a primary 3D reconstruction of the whole entheses to globally visualize the entheseal surface for selecting regions of interest (ROIs), on which observations were then performed. In each radius, three portions localized at different height levels (25, 50, and 75%) of the enthesis were selected (Figure 41). The total height was calculated as the number of horizontal slices between the level of the superior and inferior margins of the enthesis, which were visually determined. Each bounding box created in this way was 4 mm high, with the medium slice exactly located at the level of interest. The length and width of the boxes depended on the morphology of the bone itself. In general, we selected the ROIs on the medial half of the tuberosity, where biceps brachii's tendon does attach to the bone. We also ensured that these ROIs were long enough to catch a portion on the outside of the entheses, in order to investigate the transition between normal diaphyseal bone (on the medial-posterior face of the bone) and the entheseal area.

We then operated a segmentation according to the grey level values of each component. It consists of the definition of subsets or materials in order to make the software able to distinguish bone from empty canals and medullary cavities, external vacuum, and sedimentary residues such as sand. Subsequently, a binary image was obtained using a double threshold. It consists of white pixels (the elements we want to keep in the 3D reconstruction) and black pixels (the elements to exclude). Finally, using the HMH algorithm, binary slices were superposed to reconstruct the canal system of the cortical bone, to observe its three-dimensional organization.

This methodology, using µ-CT and 3D reconstructions with TIVMI® software program, has already been performed in a research focusing on trabecular bone microarchitecture during growth, with good repeatability [START_REF] Colombo | La micro-architecture de l'os trabéculaire en croissance : variabilité tridimensionnelle normale et pathologique analysée par microtomodensitométrie[END_REF].

Microstructural comparison of different types of entheseal changes

From the first observations of the final 3D reconstructions, it appeared that the most relevant level of interest for comparisons between the three groups was 50% of the enthesis height. At this medium region of the enthesis indeed, the organization of the canals of the cortical bone seemed to be less influenced by the morphology of the enthesis itself. At the upper and lower areas, a specific orientation of canals, for example, might be problematic to interpret, because they are transitional locations between a normal flat diaphysis and the most elevated part of the insertion site. Considering this, and in order to make the comparison easier, we decided to present here only the six reconstructions performed at this medium level (Figure 42). The main observations in each case are summarized in Table 50.

The 3D reconstructions of the canal system of the cortical bone, as well as the medullary cavities, concerning a presumed normal enthesis, had already been described with more details in the preliminary experimentation (Berthon et al., 2015a). The "normal" enthesis of the present study exhibited a similar type of organization regarding the canals of the cortical bone. On the medial-posterior face of the shaft, outside the enthesis, we observed a normal Haversian organization, with thin and longitudinal Havers' canals and a few transversal Volkmann's canals. On the antero-medial margin of the enthesis, the canals, which were thicker, revealed a reticulated organization with roughly oblique interconnections.

In the case of the presumed activity-related EC, observed on a probable archer, the medialposterior face of the diaphysis revealed the same longitudinal and thin organization of canals.

At the antero-medial margin, however, they appeared to be globally oriented toward the same anterior and proximal direction. The third case, with a DISH condition, showed considerable differences from the two others. Even if the longitudinal organization was preserved on the diaphysis, the canals were much larger. On the antero-medial face, the reticulation previously observed was not visible anymore. Instead, the organization appeared to be very irregular, with wide canals present in a higher density. Focusing on the organization of the canal network of the cortical bone, this preliminary exploration of the microarchitecture of an enthesis already allows the identification of variations between the normal condition and EC seemingly related to different causes. We could observe a normal pattern, already identified in a previous work (Berthon et al., 2015a), with a Haversian organization out of the enthesis and a variation at the entheseal margin. We can assume that the reticulation observed in this case may correspond to the structural adaptation of osteons to normal mechanical constraints, in accordance with Wolff's law [START_REF] Frost | Wolff's Law and bone's structural adaptations to mechanical usage: an overview for clinicians[END_REF]. Concerning the probable archer individual, there is only a slight variation from the normal organization, involving a bone remodeling with a preferential orientation of the canals. Could we consider this as the reflection of the adaptation to mechanical constraints involved in standardized gestures of specific activities like archery? In this exploratory work, and until further studies will be performed, we can at least support this hypothesis. The last case, with a metabolic disorder, is characterized by the loss of the osteonic organization inside the entheseal area. This suggests that calcification at entheses resulting from DISH condition might be related to a primary ossification process.

Finally, our preliminary results confirm that the use of µ-CT and 3D imaging can surely enhance our understanding of entheseal changes and their formation. While it is premature to give a definitive answer to the question of the distinction between mechanical and metabolic-related EC, we put forward the fact that the observations performed here are promising.

The next steps of this investigation should include larger samples in order to multiply the observations. The sampling will take into account the numerous biases inherent in studies aiming to reconstruct activities in ancient populations (e.g., [START_REF] Dutour | Activités physiques et squelette humain : le difficile passage de l'actuel au fossile[END_REF][START_REF] Dutour | Chasse et activités physiques dans la Préhistoire : les marqueurs osseux d'activités chez l'homme fossile[END_REF][START_REF] Villotte | Enthésopathies et activités des hommes préhistoriques : recherche méthodologique et application aux fossiles européens du Paléolithique supérieur et du Mésolithique[END_REF][START_REF] Meyer | Tracing patterns of activity in the human skeleton: an overview of methods, problems, and limits of interpretation[END_REF][START_REF] Jurmain | Bioarchaeology's Holy Grail: The Reconstruction of Activity[END_REF][START_REF] Milella | The effect of age, sex, and physical activity on entheseal morphology in a contemporary Italian skeletal collection[END_REF]Alves Cardoso & Henderson, 2013;[START_REF] Perréard Lopreno | Categorization of occupation in documented skeletal collections: Its relevance for the interpretation of activity-related osseous changes[END_REF][START_REF] Thomas | Bioarchaeology of the middle Neolithic: Evidence for archery among early European farmers[END_REF]. Better comparative work requires more objective criteria. We must perform a "skeletonization" method on smaller regions of the 3D reconstructions [START_REF] Blum | A transformation for extracting new descriptors of shape[END_REF][START_REF] Plougonven | Link between the microstructure of porous materials and their permeability[END_REF][START_REF] Douss | Squelettisation d'images en niveaux de gris et applications[END_REF]. It consists in creating a simplified representation of an object, in making it thinner (1 voxel wide) to keep its basic structure. It is based on the sequential 3D curve-thinning algorithm developed by [START_REF] Palágyi | A sequential 3D thinning algorithm and its medical applications[END_REF]. We obtain, in this way, a simplified modeling of the cortical microstructure allowing us to determine qualitative and quantitative parameters [START_REF] Colombo | La micro-architecture de l'os trabéculaire en croissance : variabilité tridimensionnelle normale et pathologique analysée par microtomodensitométrie[END_REF]. These parameters may be used to quantify the microarchitecture of normal and changed conditions and to test the interindividual variability. Once the methodology will be tested and validated, other susceptible etiologies for EC, such as inflammatory diseases, could be investigated, and various entheses could be analyzed. For instance, Djukic in 2016 has already been interested in the possible identification of horse riding practice in medieval series, confronting macromorphological observations and µ-CT analyses of different EC of the upper and lower limbs.

Under this framework, questions such as bilateral asymmetry or sex differentiation might be clarified in comparison with macromorphological examinations. This methodology might open up some interesting horizons for the research field on activities reconstruction, and therefore allow to build upon the knowledge regarding the lifestyles and behaviors in past populations such as those from the Hungarian Conquest period. Our observations encourage us to conduct further investigations on the microarchitecture of entheses, as well as other types of skeletal changes (e.g., Schmorl's nodes, morphological variants, spondylolysis) for which the multifactorial etiology represents an essential limit in their interpretation in terms of activity.

CONCLUSIONS

This doctoral research had two main objectives. The first one was to contribute to the research on activity reconstructions in past populations with the identification of skeletal changes that could be more reliably related to the practice of horse riding, in particular. The second objective was to use this knowledge to possibly improve our understanding of the funerary practices of the societies from the Hungarian Conquest period (10th century).

To do so, we analyzed different types of skeletal changes commonly used as indicators of activity: entheseal changes, joint changes, morphological variants, vertebral changes, traumatic lesions, as well as several indices of shape and robusticity of the lower limb bones. The comparison between two groups of individuals from a Conquest period cemetery, with and without deposit related to horse riding in their graves, and a group of modern known non-riders, from the documented collection of Lisbon, allowed identifying various skeletal changes that can be explained by the practice of horse riding. This is supported by anatomical and functional aspects, sports medicine, and previous anthropological studies led on riding populations. These skeletal changes included especially some entheseal changes of the coxal bone, femur, tibia, and calcaneus, Poirier's facet on the femoral head-neck junction, Schmorl's nodes at the thoracolumbar transition, and the vertical ovalization of the acetabulum.

Our results suggest that these skeletal changes can be used to evaluate, statistically, the possibility that a population of interest was practicing horse riding. For this purpose, the frequencies and values of these features should be compared with pertinent populations of known riders and non-riders. The data that we recorded on such collections could be used in future studies for comparative analyses.

This study took into consideration most of the pitfalls inherent to research on activityrelated skeletal changes, leading to several limitations, such as relatively limited sample sizes.

The main difficulty was the multifactorial etiology of most of the activity-related skeletal changes, such as the entheseal changes. An exploratory analysis of the microarchitecture of entheseal changes, using micro-CT acquisitions and 3D reconstructions revealed that microstructural variations could allow, with further research, distinguishing entheseal changes related to activity and those influenced by other factors.

We can consider that the two main objectives of this study were reached. It represents, indeed, a methodological contribution to the research on activity reconstructions in past populations, with the identification of skeletal changes that can probably be related to horse riding. It also revealed that, in our series from the Hungarian Conquest period, the individuals buried without a riding deposit in their graves were likely riding, in the same way as the individuals buried with a riding deposit. This funerary practice could, therefore, carry a more social or symbolic significance.

It also paved the way for future research directions, which should include the examination of larger samples with direct evidence of the practice of horse riding, from the Hungarian Conquest period but also other nomadic and semi-nomadic populations (e.g., Early-and Middle Avars, Mongols, Post-Contact Native Americans). The extension of the analyses of skeletal changes to the upper limb should also give a more complete picture of the influence of horse riding on the skeleton.

A notable conclusion that can be drawn is how essential it is to apply strict methodological criteria to avoid the major pitfalls associated with this type of research. Besides, we emphasize the fundamental importance of selecting pertinent anthropological collections, where specific activities can be assumed from direct evidence. This is one of the keys to reliably identify skeletal changes related to activity among past populations.

We consider that we have achieved most of the two objectives of this research. It represents, indeed, a methodological contribution to the research on activity reconstructions in past populations, with the identification of skeletal changes that can probably be related to the practice of horse riding. It also improved our understanding of the societies from the Hungarian Conquest period and their funerary practices, in particular.

We took into consideration most of the pitfalls inherent to research on activity-related skeletal changes, leading to several limitations, such as relatively restricted sample sizes in the archaeological groups. This represents one of the main aspects that we should improve in the future by including additional collections from the Hungarian Conquest period, but also other nomadic and semi-nomadic populations. In addition, the multifactorial etiology of the skeletal changes represented one of the main difficulties for their interpretation in terms of activity. This limitation notably concerned the entheseal changes, which can be related to mechanical factors, but also be influenced by age, sex, genetics or pathological conditions. In that regard, we performed the exploratory analysis of the microarchitecture of a well-defined and documented enthesis, the bicipital tuberosity of the radius. Using micro-CT acquisitions and 3D reconstructions of the canals of the cortical bone, we observed that some microstructural variations could allow, with further research, distinguishing entheseal changes related to activity from those related to other factors, thus contributing to improving the reconstruction of activities of past populations.

In the end, a notable conclusion that can be drawn is how essential it is to apply strict methodological criteria to avoid the major pitfalls associated with this type of research. Besides, we emphasize the fundamental importance of selecting pertinent anthropological collections, where specific activities can be assumed from direct evidence, as well as comparison groups of non-performers. These are determinant factors for the reliable identification of activity-related skeletal changes among past populations. Nous considérons que les deux objectifs de cette recherche ont été majoritairement atteints.

RÉSUMÉ

Cette étude représente, en effet, une contribution méthodologique à la recherche sur la reconstitution des activités des populations passées, avec l'identification de modifications squelettiques qui peuvent être liées de façon probable à la pratique cavalière. Notre étude a également contribué à améliorer notre compréhension des sociétés de l'époque de la Conquête

LIST OF FIGURES

(with shortened titles)

  Hélène Coqueugniot, Research Director, CNRS, UMR 5199 PACEA (Pessac, France), and, EPHE, PSL University (Paris, France) -Pr. Olivier Dutour, Professor, EPHE, PSL University (Paris, France) -Pr. Károly Gulya, Professor, University of Szeged (Szeged, Hungary) -Dr. Tamás Hajdu, Assistant Professor, Eötvös Loránd University (Budapest, Hungary) -Dr. Mónika Kiricsi, Associate Professor, University of Szeged (Szeged, Hungary) -Dr. György Pálfi, Associate Professor, University of Szeged (Szeged, Hungary) -Dr. Ildikó Pap, Emeritus Research Director, Hungarian Natural History Museum (Budapest, Hungary) -Dr. Anne-marie Tillier, Honorary Research Director, CNRS, UMR 5199 PACEA (Pessac, France) -Dr. Albert Zink, Research Director, EURAC Research, Institute for Mummy Studies (Bolzano, Italy) I am especially grateful to Dr. Ildikó Pap, Dr. Albert Zink, and Dr. Tamás Hajdu, who kindly accepted to be reviewers of this doctoral dissertation, in the French and the Hungarian doctoral process.

Anthropology

  Paul Broca of the EPHE, I started my doctoral work at the research unit PACEA (UMR 5199), in Pessac, France, attached to the CNRS, University of Bordeaux, and the French Ministry of Culture and Communication, and directed by Dr. Anne Delagnes. Most of the examination of the research materials and the writing process took place then at the Department of Biological Anthropology of the University of Szeged, in Szeged, Hungary, directed by Dr. György Pálfi. I am grateful to all academic and administrative members of the two research units who made possible my presence and the successful completion of my work, and, in particular, Régine Wortmann, Viktória Kóger, and Krisztina Mócza, for their administrative support. This research was made possible by the financial support granted by: -the Hungarian Bilateral State Scholarships of the Tempus Public Foundation (2016-2017, 2017-2018, 2018-2019); -the Grant for International Mobility of Doctoral Students from the Scientific Council of Region Ile-de-France (2015-2018); -the French-Hungarian Hubert Curien Partnership Balaton, with the projects "Anthropobiologie et archéologie des anciens peuplements de Hongrie" (2015-2016), and "Anthropologie des peuplements anciens de Hongrie (2018-2019), coordinated by Pr. Olivier Dutour and Dr. György Pálfi; -the Hungarian Institutional Doctoral Research Scholarships from the Doctoral Council of the University of Szeged (2016-2017); -and the National Research, Development and Innovation Office, Hungary (NKFIH, project K125561, dir.: Dr. György Pálfi). Furthermore, this doctoral research is associated with the project "Árpád-ház Program" of the Ministry of Human Capacities, Hungary. I express my gratitude to Dr. Sébastien Reymond, Attaché de Coopération Scientifique et Universitaire (Ambassade de France en Hongrie / Institut français de Budapest) for his interest in my French-Hungarian Cotutelle Doctorate, and to Anna Hernádi, Deputy Head (Tempus Public Foundation, Higher Education Department) for her kind assistance and contribution in the granting of scholarships during my stay in Hungary. In regards to the statistical analyses, I am greatly indebted to Frédéric Santos (PACEA) who patiently answered my numerous questions and provided insightful advice. I would like to thank Dr. Aline Thomas (National Museum of Natural History in Paris) and Dr. Stéphane Rottier (University of Bordeaux/PACEA), for their support and for showing me the way already during my MSc at the University of Bordeaux. Similarly, thanks are also due to Dr. Aminte Thomann (INRAP) for her support since my MSc, as well as for providing skeletal materials for micro-CT analyses. I am grateful to the National Museum of Natural History and Science in Lisbon (MUHNAC), University of Lisbon, and especially to Dr. Susana Garcia, Curator of the Anthropological Collection, and Dr. Judite Alves, Head of the Department of Zoology and Anthropology, for their assistance and for allowing the access to the Luís Lopes Skeletal Collection, from which a sample was used as a comparison group in this research. I also thank the members of the Archaeogenetics Laboratory, Department of Genetics of the University of Szeged, Dr. Tibor Török and Dr. Endre Neparáczki, for providing results of genetic analyses performed on some individuals from the cemetery of Sárrétudvari-Hízóföld.

  group from the documented collection of Lisbon) µ-CT micro-computed tomography (or also micro-CT) NRD no riding deposit (group of individuals from the Hungarian Conquest period) RD riding deposit (group of individuals from the Hungarian Conquest period)

Figure 1 .

 1 Figure 1. Summary of the potential risk factors for osteoarthritis (Johnson and Hunter, 2014)

Figure 2 .

 2 Figure 2. Norman horsemen depicted on the Bayeux Tapestry, ca. 1080. Embroidery, Bayeux Tapestry Museum, Bayeux, France. From http://www.hs-augsburg.de

  synthetize, those skeletal changes can be categorized in several groups: (a) spinal changes; (b) extraspinal joint changes; (c) entheseal changes; (d) morphological variants; and (e) extraspinal traumatic lesions. For clarity, we group them under the term horse riding-related skeletal changes (abbreviated as HRSC), even though their association with the practice of horse riding is, in the great majority of cases, simply assumed and not demonstrated.

Fornaciari

  et al. (2007) cite a hypertrophy of the femoral rectus muscle, femoral biceps, great adductor, small gluteus, lateral vastus, and gastrocnemius without specifying which origin or insertion sites are concerned. We assume the mention of the pectineus and soleus muscles refers to the pectineal line and soleal line, respectively. Similarly,[START_REF] Fornaciari | A great enigma of the Italian Renaissance: paleopathological study on the death of Giovanni dalle Bande Nere (1498-1526) and historical relevance of a leg amputation[END_REF] mention a strong hypertrophy of the femoral rectus muscle, femoral biceps, great adductor, small, and great gluteus without any further precision.[START_REF] Serna | Osteobiografía de dos individuos inhumados durante la Campaña del Desierto: el caso del sitio Chimpay (Argentina)[END_REF] describe in the remains of a late 19th-century individual from Argentina buried in a rich double grave the important development of the insertion zones of the adductors on both femurs -without any further detail -and put it in relation with the practice of horse riding considering the socio-historical context of the site.[START_REF] Anđelinović | Skeleton changes induced by horse riding on medieval skeletal remains from Croatia[END_REF] also mention the presence of "intertrochanteric enthesophytes"

Figure 3 .

 3 Figure 3. 3D model of an elite Hungarian mounted archer from the cemetery of Karos-Eperjesszög III (grave 11). Made by Pazirik Informatikai Kft for the exhibition "Elit alakulat" of the Herman Ottó Museum (Miskolc, Hungary). From http://elitalakulat.hu

Figure 5 .Figure 6 .Figure 7 .Figure 8 .Figure 9 .

 56789 Figure 5. Example of the grave 11 from the Hungarian Conquest period cemetery of Karos-Eperjesszög: a) picture of the grave (Révész, 1999); and b, c) reconstruction of the burial made by Pazirik Informatikai Kft for the exhibition "Elit alakulat" of the Herman Ottó Museum (Miskolc, Hungary). From http://elitalakulat.hu

Figure 10 .

 10 Figure 10. Map of the cemetery of Sárrétudvari-Hízóföld showing the distribution of graves with horse riding equipment or horse bones (Nepper, 2002, modified by Balázs Tihanyi)

Figure 11 .

 11 Figure 11. Examples of graves from the Hungarian Conquest period cemetery of Sárrétudvari-Hízóföld (10th century) with deposits of horse riding equipment (stirrups, girth buckles, and bits), sometimes associated with horse bones: a) field photographs (Nepper, 2002); and b) archaeological drawings of graves[START_REF] Nepper | Hajdú-Bihar megye 10-11. századi sírleletei I-II. (Magyarország honfoglalás és kora Árpád-kori sírleletei 3)[END_REF]

Figure 12 .

 12 Figure 12. Examples of entheseal changes that were analyzed on the coxal bone, patella, and tibia: a) anterior inferior iliac spine (COX E1); b) ischial tuberosity (COX E2); c) anterior surface of the patella (PAT E1); d) calcaneal tuberosity (CAL E1); e) soleal line (TIB E2); and f) tibial tuberosity (TIB E1). Collection of Sárrétudvari-Hízóföld (10th century)

Figure 13 .

 13 Figure 13.

Figure 14 .

 14 Figure 14. Examples of changes scored at the a) acetabular surface of the coxofemoral joint; b) femoral head of the coxofemoral joint; c) inferior and malleolar surfaces of the tibia for the ankle joint; and d) superior articular surface of the talus for the ankle joint. Collection of Sárrétudvari-Hízóföld (10th century) and documented collection of Lisbon

Figure 16 .

 16 Figure 16. Examples of coxofemoral joint changes: a) erosion of the superior part of the acetabulum; b) perifoveal osteophytosis on the femoral head, which were analyzed independently. Collection of Sárrétudvari-Hízóföld (10th century)

Figure 17 .

 17 Figure 17. Morphological variants of the femur analyzed in this study: a) Poirier's facet; b) anteroiliac plaque; c) Allen's fossa; d) posterior cervical imprint; e) third trochanter; and f) hypotrochanteric fossa. Collection of Sárrétudvari-Hízóföld (10th century)

Figure 18 .

 18 Figure 18. Examples of small and large Schmorl's nodes. Collection of Sárrétudvari-Hízóföld (10th century)

  see Chapter 1, II.B and II.D.1).

Figure 19 .

 19 Figure 19. Example of unilateral spondylolysis (or partially healed spondylolysis) on a 5th lumbar vertebra. Collection of Sárrétudvari-Hízóföld (10th century)

Figure 20 .

 20 Figure 20. Examples of healed fractures on the lower limb, at the: a) tibia, and b) comparison with the healthy bone on the right; and at the: c) fibula, and d) comparison with the healthy bone on the right. Collection of Sárrétudvari-Hízóföld (10th century)

Figure 21

 21 Figure 21. a) Measurements of the maximum vertical and horizontal diameters of the acetabulum, and examples of b) an acetabulum with a shape intermediate between circular and a horizontal ovalization (index = 0.971), and c) an acetabulum exhibiting a strong vertical ovalization (index = 1.082). The discontinuous lines represent exact circles for reference

  -width index M2/M1 Talar width/Talar length TAL I2 Length-height index M3/M1 Talar height/Talar length TAL I3 Trochlear index M5/M4 Transverse trochlear breadth/Trochlear length Calcaneus CAL I1 Length-width index M2/M1 Breadth across the sustentaculum/Maximum length CAL I2 Length-height index M4/M1a Height of body/Total length

Figure 22 .

 22 Figure 22. Case of slipped capital femoral epiphysis in an individual from Sárrétudvari-Hízóföld

Figure 23 .

 23 Figure 23. Case of DISH, with ossification of the right side anterior longitudinal ligament on vertebrae from an individual from the collection of Lisbon

Figure 24 .

 24 Figure24. Frequency of entheseal changes observed for young and mature adult individuals (YMA) from the Hungarian groups with (RD) and without riding deposit (NRD) and the comparison group from Lisbon (LIS). See Table9for the entheses' codes; * indicates statistically significant differences between groups (see Table17)

Figure 25 .

 25 Figure 25. Frequency of entheseal changes observed in individuals in all adult age categories from the Hungarian groups with (RD) and without riding deposit (NRD) and the comparison group from Lisbon (LIS). See Table9for the entheses' codes; * indicates statistically significant differences between groups (see Table20)

  Figure 26. Frequency of joint changes observed for young and mature adult individuals (YMA) from the Hungarian groups with (RD) and without riding deposit (NRD) and the comparison group from Lisbon (LIS)

Figure 28 .

 28 Figure 28. Frequency of morphological variants of the femur in the Hungarian groups with (RD) and without riding deposit (NRD) and the comparison group from Lisbon (LIS).* indicates statistically significant differences between groups (see Table34)

Figure 29 .Figure 30 .

 2930 Figure 29. Frequency of Schmorl's nodes by size on the thoracic (T), lumbar (L), and the first sacral (S) vertebrae in the Hungarian groups with (RD) and without riding deposit (NRD), and the comparison group from Lisbon (LIS)

Figure 33 .

 33 Figure 33. Distribution of fractures by anatomic region in the Hungarian groups with (RD) and without riding deposit (NRD), and the comparison group from Lisbon (LIS). No fracture was recorded on the head

Figure 34 .

 34 Figure 34. Index of ovalization of the acetabulum (vertical/horizontal diameter), by side and combined, on unpaired coxae in the Hungarian groups with (RD) and without riding deposit (NRD) and in the comparison group from Lisbon (LIS). * indicates statistically significant differences between groups (see Table 42)

Figure 35 .

 35 Figure 35. Asymmetry of the index of ovalization of the acetabulum on paired coxae in the Hungarian groups with (RD) and without riding deposit (NRD), and the comparison group from Lisbon (LIS)

Figure 36 .

 36 Figure 36. Difference between the right and left indices of ovalization of the acetabulum (IOA) on paired coxae in the Hungarian groups with (RD) and without riding deposit (NRD), and the comparison group from Lisbon (LIS)

  indicators of physical stress in past populations (see Chapter 2, III.A.4.a). We analyzed the presence of Schmorl's nodes for each vertebra and different groups of vertebrae (upper thoracic, lower thoracic, lumbar levels), taking into account the size of nodes (small and large; see Chapter 2, III.A.4.a; Table

Figure 37 .

 37 Figure 37. Oblique fracture of a left clavicle that might be related to a fall from a height. Collection of Sáarrétudvari-Hízóföld (10th century)

  ),[START_REF] Sarry | La sépulture multiple laténienne du site de Gondole (Le Cendre, Puy-de-Dôme)[END_REF][START_REF] Baillif-Ducros | La pratique de la monte à cheval au haut Moyen Âge (fin Ve-VIIe siècle) dans le nord-est de la Gaule. État des connaissances archéologiques[END_REF], which is the calculation of a vertical/horizontal diameter index, or, index of ovalization of the acetabulum (IOA). Our results revealed that the individuals from burials with archaeological items related to horse riding showed an increased overall acetabular vertical ovalization compared with the ones from the graves with no riding-related goods in the Hungarian series, as well as with individuals from a modern population from Lisbon. The individuals from this comparison group almost certainly did not practice horse riding, intensively or regularly.

Figure 38 .

 38 Figure 38. Reconstruction illustrating the possible contact between the femoral head and the superior part of the acetabulum (white arrow) in the riding position, with the pelvis in retroversion. Drawing by Luca Kis

  The entheseal changes at the ischial tuberosity and anterior inferior iliac spine of the coxal bone, the adductor tubercle, trochanteric fossa, and linea aspera of the femur, the soleal line of the tibia, and the calcaneal tuberosity. Since only entheseal changes at the adductor tubercle of the distal femur and the calcaneal tuberosity showed significant differences between groups on a sample that strictly excluded old adult individuals, and thus, limited the influence of aging, these two entheses are considered as the most promising ones;  Poirier's facet on the femoral neck, which should be distinguished from other modifications of the femoral head-neck junction;  Schmorl's nodes, especially at the thoracolumbar transition, and including large nodes; A vertical ovalization of the acetabulum.

  One of the main objectives of this study was to represent a methodological contribution to the bioanthropological research on activity-related skeletal changes, by investigating the possible influence of the practice of horse riding on the skeletal specifically. In the end, we can claim that this study represents the first methodological contribution to the research on horse riding-related skeletal changes to meet all the following criteria:  It relies on an anthropological collection of confirmed horse riders, with a direct association between particular individuals and the activity provided by archaeological evidence;  It includes a comparison group from a population in which the practice of horse riding was very unlikely;  It is based on a systematic analysis of different types of skeletal changes commonly used as indicators of activity and behaviors in past populations;  It relies on samples large enough to allow statistical analyses (unlike several studies based on single cases);  It takes into account multiple methodological bias factors such as sex, age, and pathological conditions, and attempts to limit their influence using strict analytical criteria;  It discusses the observed skeletal changes and their possible relationship with the practice of horse riding in light of anatomical and functional aspects, with the support of sports medicine literature.Specifically, we must highlight the pertinence of the archaeological collection that was used, and which represents an essential strength of this study. The series from the 10th-century cemetery of Sárrétudvari-Hizóföld included, indeed, 32 graves with either a deposit of equipment related to horse riding, either horse bones, or both, in association with the individuals. The strict methodological criteria used in this investigation led us to include 17 of these individuals, which represents, to the best of our knowledge, the largest homogeneous anthropological sample investigated for horse riding-related skeletal changes for which archaeological evidence provides a direct link between each individual and this activity.

Figure 39 .

 39 Figure 39. Reconstruction of mounted archery in the style of the populations from the Hungarian Conquest period, from the Ópusztaszer National Heritage Park, in Hungary. Photo by Luca Kis, edited by Fara MuciFinally, the multifactorial etiology of the entheseal changes was the reason that led us to perform an exploratory analysis of the microstructure of an enthesis, using µ-CT acquisitions and 3D reconstructions (see XI below). The objective was to determine if "mechanical" entheseal changes, related to activity, could be distinguished from changes related to other causes (see II.D.2.c). This preliminary investigation paved the way for further research (see XI below).

  . In 1986, Dutour investigated the skeletal remains of Neolithic Saharan populations of hunters-fishermen-gatherers from Mali and Niger and identified the presence of EC on the upper limbs of several individuals. The changes observed at the bicipital tuberosity of the radius, associated with asymmetrical changes at other insertion sites (for triceps brachii and teres minor especially), led to the hypothesis of the habitual practice of archery. In 2014, Thomas investigated the frequency of EC in a Neolithic population from the Cerny culture (Paris Basin, France). Among 36 identified adult males, 13 were buried in association with arrowheads. Her results reveal a higher frequency of EC at several insertion sites among the group of individuals buried with arrowheads, the difference with the other group being significant for the radial tuberosity in particular. Those are examples of studies suggesting archery as an activity prone to lead to EC at this specific insertion site.

1)

  The first individual is presumed to represent the normal aspect of the enthesis. He comes from the Merovingian-Carolingian (7-10th centuries) cemetery of Val-de-Reuil "Le Chemin aux Errants", in Normandy, France. The excavation was led by the French National Institute for Preventive Archaeology (INRAP), under the supervision of Yves-Marie Adrian, in 2012. A

Figure 40 .

 40 Figure 40. Three pairs of analyzed radii for normal condition (VDR4114), "mechanical" entheseal changes (EC) (SH179), and "metabolic" entheseal changes (BACS173). Photos by William Berthon & Olivier Dutour

Figure 41 .

 41 Figure 41. Example of a 3D reconstruction of the enthesis showing the selection of the regions of interest at different height levels. SH179, "presumed archer", left radius; reconstructions by William Berthon

Figure 42 .

 42 Figure 42. 3D reconstruction of the canals of the cortical bone for each enthesis, at 50% of the enthesis height. The normal aspect (VDR4114) shows, in particular, a reticulated organization at the medial margin; the "mechanical" EC (SH179) are characterized by a preferential orientation of the canals, while the "metabolic" EC (BACS173) exhibit an irregular, large and dense organization; reconstructions by William Berthon

  hongroise et de leurs pratiques funéraires, en particulier.Nous avons tenu compte de la plupart des écueils inhérents à la recherche sur les marqueurs osseux liés aux activités, ce qui a entraîné plusieurs limitations, comme la taille relativement restreinte des échantillons au sein des groupes archéologiques. C'est l'un des principaux aspects que nous devrons améliorer à l'avenir en incluant des collections supplémentaires de la période de la Conquête hongroise, mais aussi issues d'autres populations nomades et semi-nomades. De plus, l'étiologie multifactorielle des modifications squelettiques représente l'une des principales difficultés pour leur interprétation en termes d'activité. Cette limitation concerne notamment les modifications des enthèses, qui peuvent être liées à des facteurs mécaniques, mais aussi être influencées par l'âge, le sexe, des facteurs génétiques ou certaines pathologies. À cet égard, nous avons effectué l'analyse exploratoire de la microarchitecture d'une enthèse bien définie et documentée, la tubérosité bicipitale du radius. À l'aide d'acquisitions micro-CT et de reconstructions 3D des canaux de l'os cortical, nous avons observé que certaines variations microstructurales pourraient permettre de distinguer les modifications des enthèses liées aux activités de celles liées à d'autres facteurs, contribuant ainsi à améliorer les reconstructions des activités des populations passées. Cela encourage donc à mener des recherches plus approfondies sur le sujet.Au final, une conclusion notable qui peut être tirée de cette recherche doctorale est qu'il est essentiel d'appliquer des critères méthodologiques stricts pour éviter les principaux écueils associés à ce type de recherche. En outre, nous tenons à souligner l'importance fondamentale de sélectionner des collections anthropologiques pertinentes, pour lesquelles la pratique d'activités spécifiques peut être assumée à partir de preuves directes, ainsi que des groupes de comparaison de non-pratiquants. Il s'agit là de facteurs déterminants pour l'identification fiable de modifications squelettiques liées aux activités au sein des populations du passé.ÖSSZEFOGLALÓBizonyos, az emberi csontokon megfigyelhető patológiás és nem patológiás elváltozások összefüggésbe hozhatók az egyén által rendszeresen végzett fizikai aktivitásokkal. Ez annak köszönhető, hogy a csontok -mind formájukban, mind szerkezetükben -képesek adaptálódni az őket érő mechanikai behatásokhoz. Az egykor élt népességek körében végzett fizikai aktivitások csontelváltozásokon alapuló rekonstrukcióját a történeti embertani iskolák a "Bioarcheológia Szent Gráljának" tekintik; ez a terület tulajdonképpen egyfajta végső célt reprezentál, ami csak nagy nehézségek árán érhető el, mivel számos metodológiai buktatót kell számításba venni a vizsgálatok során. Az elmúlt évtizedekben a fizikai aktivitások közül elsősorban a lovaglás vonta magára a történeti embertannal és paleopatológiával foglalkozó kutatók figyelmét, mivel annak elterjedése mélyreható és hosszútávú változásokat hozott az emberiség kulturális evolúciójába, olyan meghatározó elemeket érintve, mint a kereskedelem, a letelepedés, a hadászat, a létfenntartás, a társadalmi szerveződés vagy a politikai ideológia. A szakirodalomban számos léziót írtak le az úgynevezett "lovagló szindrómával", azaz a rendszeres vagy intenzív lovaglással összefüggésben, azonban az erre a kutatási területre fókuszáló vizsgálatokat többek közt a csontelváltozások specifikusságának hiánya és multifaktoriális etiológiája is nehezíti. Az említett tényezők mellett az is problémát jelent, hogy a legtöbb tanulmányban hiányzik az egyént az adott fizikai aktivitáshoz kapcsoló bizonyíték és az összehasonlítási csoport. A fentiek együttesen gyakran ahhoz vezetnek, hogy a léziók csak limitáltan vagy megbízhatatlanul interpretálhatók egy specifikus fizikai aktivitás, például a lovaglás szempontjából.Régészeti és történeti források tanúsága szerint a 9. és 10. század fordulóján erős, lovasíjász hadsereggel rendelkező, nagyállattartásra berendezkedett törzsek hódították meg a Kárpátmedencét, ami egy évszázaddal később a Magyar Királyság megalapításához vezetett. Az erre a korszakra keltezhető temetőkben feltárt sírokból gyakran kerülnek elő íjászatra és/vagy lovaglásra utaló mellékletek, valamint lócsontok. Az említett mellékletek és az embertani leletek közti szoros kapcsolatot, valamint a jól ismert történeti hátteret figyelembe véve feltételezhetjük, hogy az ezekben a sírokban nyugvó egyének rendszeresen lovagoltak életük során. Ennek fényében a fent említett populációk a legmegfelelőbbek közé tartoznak abból a szempontból, hogy metodológiai vizsgálatokat végezzünk rajtuk az aktivitással, különösen a rendszeres lovaglással összefüggésbe hozható csontelváltozásokra vonatkozóan. Doktori kutatási projektemnek két fő célkitűzése volt. Az első célom az volt, hogy hozzájáruljak az egykor élt népességek fizikai aktivitásainak rekonstrukcióját célzó kutatások fejlődéséhez olyan csontelváltozások azonosításával, amik megbízhatóbban összefüggésbe hozhatók a rendszeresen végzett lovaglással. A második célom az volt, hogy a magyar honfoglalás kori társadalom temetkezési szokásaival kapcsolatos ismereteink bővítése révén új társadalomrégészeti adatokat szolgáltassak. Vizsgálataimba csak a felnőtt férfiakat vontam be, hogy ezzel minimalizáljam az életkor és a nemiség csontelváltozások kialakulására gyakorolt zavaró hatását. Ennek megfelelően Sárrétudvari-Hízóföld 10. századi temetőjéből 67 egyén embertani leletei képezték a vizsgálati anyagot, amit két csoportra osztottam aszerint, hogy a temetkezés tartalmazott-e lovaglásra utaló sírmellékletet (17 "lovas" és 50 "nem lovas" egyént különítettem el). Ezen felül egy modern (19-20. századi) összehasonlító csoportot is kiválasztottam, amit a lisszaboni dokumentált embertani gyűjteményből származó 47 olyan egyén alkotott, akiknél előzetesen ki lehetett zárni a lovas életmódot. Bizonyos elemzések során a fiatal és érett felnőtt korú egyéneket is elkülönítettem egymástól, hogy ezzel minimalizáljam az öregedéssel járó csonttani folyamatok zavaró hatását. Doktori kutatási projektem keretein belül olyan léziótípusokat vizsgáltam, amelyeket a vonatkozó szakirodalomban a történeti népességek életmódjának és rendszeresen végzett fizikai aktivitásainak az indikátoraiként tartanak számon. Ezek a következők: enthesealis elváltozások (az izmok kapcsolódási területeinél), ízületi elváltozások, morfológiai variációk, csigolyaléziók és traumás eredetű elváltozások. Az egyes csontok alakját és robuszticitását leíró indexek meghatározásához további direkt méréseket is végeztem az alsó végtag csontjain. A megfelelő léziók kiválasztásánál anatómiai és funkcionális szempontokat is figyelembe vettem, és a lovaglással kapcsolatos bioantropológiai és sportorvosi szakirodalomi adatokat is felhasználtam. A statisztikai vizsgálatok többnyire szignifikáns különbséget mutattak ki a magyar honfoglalás kori vizsgálati csoportok (lovaglásra utaló sírmellékletekkel vagy anélkül) és a lisszaboni széria között. Ezek a különbségek leginkább olyan csontelváltozások esetében jelentkeztek, amelyek kialakulását a rendszeres lovaglással lehet magyarázni. Ilyenek például a medencecsonton, a combcsonton, a sípcsonton és a sarokcsonton megfigyelhető bizonyos enthesealis elváltozások, a combcsont nyakának morfológiai adaptációja, a gerinc alsó háti és ágyéki szakaszán jelentkező porckorongsérv, illetve a csípőízületi vápa ovalizációja. Eredményeim azt mutatják, hogy ezek a léziók alkalmasak lehetnek arra, hogy statisztikai alapon nagy bizonyossággal megítélhessük, hogy egy adott populáció rendszeresen végzett-e lovas tevékenységet. Ennek eldöntéséhez a fent említett csontelváltozások gyakoriságait és értékeit kell összehasonlítani a releváns "lovas" és "nem lovas" populációkban. Eredményeim e tekintetben fontos összehasonlítási alapként szolgálhatnak a jövőbeni kutatások számára is. Továbbá úgy vélem, hogy a fent említett léziók mellett a felső végtagot, különös tekintettel a kulcscsontot érintő akut traumás eredetű töréseknek a csontváz más régióit érintő törésekhez képesti nagyobb előfordulási gyakoriságát is érdemes lehet indikátorként figyelembe venni az összehasonlítások során. Másfelől, az általam vizsgált csoportok összehasonlító elemzése arra is rámutatott, hogy a Sárrétudvari-Hízóföld 10. századi temetőből előkerült, lovaglásra utaló mellékletek nélküli sírokban nyugvó egyének a lovaglásra utaló sírmellékletekkel eltemetett egyénekhez hasonlóan életük során valószínűleg rendszeresen lovagoltak. Ez a megállapítás magyarázattal szolgálhat arra az ellentmondásra vonatkozóan, hogy míg az írott források nagyszámú lovast említenek a honfoglalás kori populációkban, addig a honfoglalás kori Kárpát-medence területén feltárt sírok csak kis része tartalmazott lovaglásra utaló sírmellékleteket. A fentiek következményeként a vonatkozó mellékletek elhelyezése a sírokban vélhetően sokkal inkább valamifajta társadalmi vagy egyéb szimbolikus jelentéstartalommal bírhatott. Doktori kutatási projektem két fő célkitűzését teljesítettem. Vizsgálataim során olyan csontelváltozásokat azonosítottam, amelyek a rendszeres lovaglás következményeként alakulhattak ki, így kutatási projektem egy metodológiai hozzájárulásnak tekinthető az egykor élt népességek fizikai aktivitásainak rekonstruálására irányuló vizsgálatok szempontjából. Kutatási eredményeim révén a magyar honfoglalás kori társadalommal, különösen a temetkezési szokásokkal kapcsolatos ismereteink is bővültek. Vizsgálataim során arra törekedtem, hogy az aktivitással kapcsolatos csontelváltozások kutatásával együtt járó nehézségek, buktatók többségét figyelembe vegyem. Ez bizonyos limitációkat vont maga után, így például viszonylag kis mintaszámot eredményezett a honfoglalás kori vizsgálati csoportokban. Doktori kutatási projektemen belül az alacsony mintaszám jelenti az egyik olyan fő területet, ami a jövőben fejlesztésre szorul, amit további magyar honfoglalás kori anyagok, illetve egyéb nomád és félnomád populációk bevonása révén érhetek majd el. A fentiek mellett a csontelváltozások multifaktoriális etiológiája jelentette az egyik fő nehézséget a léziók fizikai aktivitás szempontjából történő interpretációja során. Ez a nehézség az enthesealis elváltozások értékelése során különösen megmutatkozott, mivel azok kialakulását a mechanikai tényezők mellett az egyén életkora, neme, genetikai háttere és különböző kórképek is befolyásolhatják. Mindezek tudatában doktori kutatási projektem keretében egy jól definiált és jól dokumentált enthesis -a kétfejű karizom (musculus biceps brachii) tapadási felületéül szolgáló orsócsonti érdesség (tuberositas radii)mikroszerkezetének a felderítését szolgáló vizsgálatot is elvégeztem. A tömör csontállomány csatornáiról készült micro-CT felvételek és 3D rekonstrukció révén azt a megfigyelést tettem, hogy néhány mikroszerkezetbeli variáció -további kutatások elvégzését követően -lehetővé teheti majd az aktivitással összefüggésben létrejövő enthesealis csontelváltozások elkülönítését a más tényezők miatt kialakulóaktól, így elősegítve az egykor élt népességek körében végzett fizikai aktivitások rekonstrukciójának a fejlődését. Végezetül fontos megjegyezni, hogy a szigorú metodológiai kritériumok alkalmazása nélkülözhetetlen az ezzel a típusú kutatással együtt járó fő nehézségek, buktatók elkerülése végett. Mindemellett, a vizsgálati anyagul szolgáló megfelelő antropológiai gyűjtemények kiválasztásának az alapvető jelentőségét is fontos kihangsúlyozni. Nemcsak azoknak az anyagoknak a körültekintő kiválasztása fontos, ahol a specifikus fizikai aktivitás végzésére közvetlen bizonyítékok utalnak, hanem azoknak az összehasonlító gyűjteményeknek a kiválasztása is, ahol nem végezték az adott fizikai aktivitást. A fentiek kulcsfontosságúak ahhoz, hogy az egykor élt népességekben megbízhatóan tudjuk azonosítani az aktivitással összefüggésbe hozható csontelváltozásokat.

Figure 1 .Figure 2 .Figure 3 .Figure 4 .Figure 5 .Figure 6 .Figure 7 .Figure 8 .Figure 9 .Figure 10 .Figure 11 .Figure 12 .Figure 13 .Figure 14 .Figure 15 .Figure 16 . 76 Figure 17 .Figure 18 .Figure 19 .Figure 20 .Figure 22 .Figure 23 .Figure 24 .Figure 25 .Figure 26 .Figure 27 .Figure 28 .Figure 29 .Figure 30 .Figure 31 .Figure 32 .Figure 33 .Figure 34 .Figure 35 .Figure 36 .Figure 37 .Figure 38 .Figure 39 .Figure 40 .Figure 41 .Figure 42 .

 123456789101112131415167617181920222324252627282930313233343536373839404142 Figure 1. Summary of the potential risk factors for osteoarthritis .......................................... 20

the

  Hungarian groups with (RD) and without riding deposit (NRD) and the comparison group from Lisbon (LIS), and statistical comparison ....................................................................... 116 Table 37. Frequency of Schmorl's nodes by size on the thoracic (T), lumbar (L), and the first sacral (S) vertebrae in the Hungarian groups with (RD) and without riding deposit (NRD) and the comparison group from Lisbon (LIS), and statistical comparison taking size into account ................................................................................................................................................ 118 Table 38. Frequency and distribution of fractures in the Hungarian groups with (RD) and without riding deposit (NRD) and the comparison group from Lisbon (LIS), and statistical comparison ............................................................................................................................. 123 Table 39. Interobserver (A-B) and intraobserver (A1-A2) agreement in the measurement of the maximum diameters of the acetabulum ............................................................................ 125 Table 40. Composition of the samples of observable acetabula in the Hungarian groups with (RD) and without riding deposit (NRD) and in the comparison group from Lisbon (LIS) ... 125 Table 41. Summary statistics of the index of ovalization of the acetabulum in the Hungarian groups with (RD) and without riding deposit (NRD) and in the comparison groups from Lisbon (LIS) ....................................................................................................................................... 125 Table 42. Statistical comparison for the index of ovalization of the acetabulum (IOA) between the Hungarian groups with (RD) and without riding deposit (NRD) and the comparison group from Lisbon (LIS) .................................................................................................................. 126 Table 43. Summary statistics for the asymmetry of the index of ovalization of the acetabulum measured on paired coxae in the Hungarian groups with (RD) and without riding deposit (NRD) and in the comparison group from Lisbon (LIS), and statistical comparison ........................ 127 Table 44. Evaluation of the asymmetry (right minus left value) of the index of ovalization of the acetabulum on paired coxae in the Hungarian groups with (RD) and without riding deposit (NRD) and in the comparison group from Lisbon (LIS), and statistical comparison between groups ..................................................................................................................................... 128 Table 45. Summary statistics of the indices of shape and robusticity in the Hungarian groups with (RD) and without riding deposit (NRD) and in the comparison groups from Lisbon (LIS) ................................................................................................................................................ 130 Table 46. Statistical comparison for the indices of shape and robusticity in the Hungarian groups with (RD) and without riding deposit (NRD) and in the comparison groups from Lisbon (LIS) ....................................................................................................................................... 131 Table 47. Summary statistics for the asymmetry of indices of shape and robusticity calculated from paired bones in the Hungarian groups with (RD) and without riding deposit (NRD) and in the comparison group from Lisbon (LIS) .............................................................................. 132 Table 48. Statistical evaluation of the asymmetry of indices of shape and robusticity calculated from paired bones in the Hungarian groups with (RD) and without riding deposit (NRD) and in the comparison group from Lisbon (LIS) .............................................................................. 133 Table 49. Evaluation of the asymmetry (right minus left value) of the indices of shape and robusticity calculated from paired bones in the Hungarian groups with (RD) and without riding deposit (NRD) and in the comparison group from Lisbon (LIS), and statistical comparison between the three groups ........................................................................................................ 134

Table 1 . Summary of the spinal skeletal changes associated with horse riding in the anthropological literature

 1

Table 2 . Summary of the extraspinal joint changes associated with horse riding in the anthropological literature Anatomical region Localization of observed extraspinal joint changes References

 2

	Pelvis	Sacroiliac joint	Bradtmiller, 1983; Üstündağ & Deveci, 2011

Table 3 . Summary of the entheseal changes associated with horse riding in the anthropological literature (1/2) Bone Site of the observed entheseal changes Muscles attached to the site (o. = origin site; i. = insertion site) References

 3

		Ilium posterior (superior and posterior	Gluteus maximus (o.); Gluteus medius (o.); Gluteus minimus	Miller, 1992; Pálfi, 1992; Anđelinović et al., 2015;
		to the inferior gluteal line)	(o.)	Ciurletti, 2017
		Pubic body	Adductor brevis (o.)	Miller, 1992
	Coxal
	bone	Ischial tuberosity	Semimembranosus (o.); Semitendinosus (o.); Biceps femoris	Pálfi, 1992; Molleson & Hodgson, 1993; Ciurletti,
			(o., long head)	2017; Djukic et al., 2018
		Inferior pubic ramus and ramus of
		ischium (medial border)

Table 3 . Summary of the entheseal changes associated with horse riding in the anthropological literature (2/2) Bone Site of the observed entheseal changes Muscles attached to the site (o. = origin site; i. = insertion site) References Femur

 3

Middle medial lip of linea aspera

Adductor magnus (i.); Adductor longus (i.); Adductor brevis (i.); Vastus medialis (o.)

Table 4 . Summary of the morphological variants associated with horse riding in the anthropological literature

 4

Table 5 . Summary of extraspinal traumatic lesions associated with horse riding in the anthropological literature Anatomical region Traumas observed References

 5

		Nasal bone, frontal bone fracture	Khudaverdyan et al., 2016; Karstens et al.,
			2018 (nasal)
	Head	Mastoid process (unilateral thickening and	Panzarino & Sublimi Saponetti, 2017
		volume increase due to a trauma)
		Unspecified skull fracture	Anđelinović et al., 2015
		Ribs fracture	Pálfi, 1992; Willey, 1997; Aguayo, 2012;
	Trunk		Khudaverdyan et al., 2016; Karstens et al.,
			2018
		Clavicle fracture	Pálfi, 1992; Willey, 1997; Wentz & de
			Grummond, 2009; Khudaverdyan et al., 2016
		Humerus fracture	Wentz & de Grummond, 2009; Dutour &
			Buzhilova, 2014
		Shoulder fracture/dislocation	Panzarino & Sublimi Saponetti, 2017
	Upper limb	Forearm fracture (radius, ulna)	Pálfi, 1992; Willey, 1997 (radius); Karstens et
			al., 2018 (ulna)
		Wrist fracture	Pálfi, 1992 (bilateral distal radiuses)
		Finger bones	Willey, 1997 (2nd); Dutour & Buzhilova, 2014
			(5th)
		Unspecified upper extremities fractures	Reinhard & Wall, 2002 (from abstract only)
		Avulsion of lesser trochanter of femur	Pulcini, 2014
		Cutting wound on femur inflicted with an	Pulcini, 2014
		upward movement (i.e., by an opponent on
		foot)
		Knee sprain	Langlois & Gallien, 2006
		Tibia fracture	Pálfi, 1992; Langlois & Gallien, 2006; Karstens
			et al., 2018
		Stress fractures (via radiographic assessment) Reinhard & Wall, 2002
		Oblique fracture tibia-fibula	Pap, 1985
	Lower limb	Proximal tibiofibular synostosis	Khudaverdyan et al., 2016
		Fibula fracture	Pálfi, 1992; Langlois & Gallien, 2006; Bagagli et
			al., 2012; Karstens et al., 2018
		Ankle sprain (calcification of the interosseous	Pálfi, 1992; Langlois & Gallien, 2006
		ligament tibia-fibula)
		Calcaneal fracture	Angel, 1982
		Other tarsal bones fracture	Willey, 1997 (lateral cuneiform)
		Metatarsal fracture	Willey, 1997 (5th); Aguayo, 2012
		Foot phalange fracture	Aguayo, 2012
		Foot fractures	Pálfi, 1992

Table 6 (

 6 for details on the results, see Appendix 8). A separate analysis of the entheseal changes and joint changes will include only the young adults, and young or mature adults (see III.C.2 below).

Table 6 . Summary of the results of the age estimation in the Hungarian archaeological groups with (RD) and without riding deposit (NRD), based on the changes at the sacropelvic surface of the ilium (Schmitt, 2005) Categories based on the age estimation [age interval] Number of individuals in the RD group Number of individuals in the NRD group

 6

	Young Adults [20-29]	3	3
	Young or Mature Adults [20-49]	4	27
	Mature Adults [30-49]	0	0
	Mature or Old Adults [≥ 30]	6	13
	Old Adults [≥ 50]	0	2
	Indeterminate Adults [≥ 20]	4	5
	Total	17	50

Table 7 . Summary of the results of the age estimation in the comparison group from Lisbon (LIS), based on the changes at the sacropelvic surface of the ilium (Schmitt, 2005) Categories based on the age estimation [age interval]

 7

	Number of individuals
	in the LIS group

Table 8 . Comparison between the estimated age based on the changes at the sacropelvic surface of the ilium (Schmitt, 2005) and the known age in the documented collection of Lisbon Estimated age Known age Estimated age Known age

 8

	20-29	20	30-59	46
	20-49	20	30-59	47
	20-29	21	30-59	47
	20-29	27	30-59	47
	20-39	28	30-59	47
	20-29*	30	20-59	48
	20-49	30	>40	48
	20-49	31	30-59	49
	20-39	31	>50	50
	20-39	32	>40	50
	30-59	33	30-59	50
	>40*	35	20-49*	50
	20-49	37	20-59	51
	30-59	37	30-59	51
	30-59	38	30-59	52
	20-59	38	30-59	52
	30-59	39	>40	53
	20-49	39	30-59	53
	20-49	40	30-59	53
	30-59	40	30-59	53
	30-59	43	>50	54
	>40	43	30-59	54
	30-59	45	30-59	56
	30-59	45

* indicates that the known age is not included within the estimated age interval

Table 9 . Entheses investigated in the analysis of entheseal changes Bone Enthesis study code Site of the observed changes Muscles attached to the site (o. = origin site; i. = insertion site)

 9

	Type of enthesis
	(F = fibrous; FC =
	fibrocartilaginous)

Medial lip: Adductor magnus (i.); Adductor longus (i.); Adductor brevis (i.); Vastus medialis (o.) Lateral lip: Vastus lateralis (o.); Biceps femoris (o., short head) FC Most of these entheses and their type were reviewed by

[START_REF] Villotte | Enthésopathies et activités des hommes préhistoriques. Recherche méthodologique et application aux fossiles européens du Paléolithique supérieur et du Mésolithique[END_REF]

; see Appendix 4 for muscles functions

Table 10 . Joints included in the analysis of joint changes

 10

	Joint region	Joint	Bone involved in the joint	Articular surface scored
	Hip	Acetabulofemoral	Coxal bone Femur	Acetabulum Femoral head
	Knee	Patellofemoral Tibiofemoral	Femur Patella Femur Tibia	Patellar surface Medial and lateral articular facets Medial and lateral condyles Medial and lateral condyles
			Tibia	Inferior and malleolar articular surfaces
	Ankle	Talocrural	Fibula	Malleolar articular surface
			Talus	Superior, medial and lateral articular surfaces

Table 11 . Morphological variants of the femur investigated in the study

 11

	Morphological variant code	Morphological variant	Location on the femur
	FEM V1	Poirier's facet	Anterior femoral head-neck junction
	FEM V2	Anteroiliac plaque	Anterior femoral head-neck junction
	FEM V3	Allen's fossa	Anterior femoral head-neck junction
	FEM V4	Posterior cervical imprint	Posterior femoral head-neck junction
	FEM V5	Third trochanter	Gluteal tuberosity
	FEM V6	Hypotrochanteric fossa	Lateral to gluteal tuberosity

Table 12 . Scoring criteria for Schmorl's nodes, from Üstündağ (2009), after Knüsel et al. (1997)

 12

	Score	Description of the lesions
	Small Schmorl's nodes (1)

Table 13 . Bones and anatomical regions examined for fractures Region Bones

 13

	Head	Skull Mandible
		Scapula
		Clavicle
	Upper limb	Humerus Radius, Ulna
		Carpal bones
		Metacarpals, Hand phalanges
	Thorax	Ribs
		Sacrum
		Coxal bone
		Femur
	Lower limb	Patella
		Tibia, Fibula
		Tarsal bones
		Metatarsals, Foot phalanges

Table 14 . Indices of shape and robusticity calculated from direct measurements on the lower limb bones and used for intergroup comparisons Bone Index code Index name Formula and definition (x 100; in mm) Measurement codes from Martin (re-edited by Bräuer, 1988)

 14

		FEM I1	Length-thickness (robusticity) index	M8/M2	Circumference of midshaft/ Physiological (bicondylar) length
		FEM I2 Pilastric index	M6/M7	Anteroposterior diameter of midshaft/ Mediolateral diameter of midshaft
	Femur	FEM I3 Platymeric index	M10/M9	Subtrochanteric anteroposterior diameter/ Subtrochanteric mediolateral diameter
		FEM I4	Epicondylar width-transverse shaft diameter index	M7/M21	Mediolateral diameter of midshaft/ Epicondylar width
		FEM I5	Head robusticity index	(M18+M19)/M2	(Vertical head diameter+Transverse head diameter)/ Physiological length
	Patella PAT I1 Height-width index M1/M2	Maximum height/Maximum width
	Tibia	TIB I1 TIB I2 Platycnemic index M9a/M8a Length-thickness (robusticity) index M10b/M2	Minimum circumference of shaft/ Physiological length Mediolateral diameter at nutrient foramen/ Anteroposterior diameter at nutrient foramen

Table 15 . Frequency of all entheseal changes observed in the young and mature adult individuals (YMA) from the Hungarian groups with (RD) and without riding deposit (NRD) and the comparison group from Lisbon (LIS), and statistical comparison

 15

		RD YMA	NRD YMA	LIS YMA	p	p exact adjusted
		N	n n/N	N	n n/N	N	n n/N	exact	RD-NRD RD-LIS NRD-LIS
	Left	70 10 14% 249	52 21% 336 38 11%	.007	.474	.541	.005
	Right	64	9 14% 288	51 18% 350 36 10%	.025	.766	.766	.023
	Left+Right	134 19 14% 537 103 19% 686 74 11% < .001	1	1	< .001

Fisher's exact test, two-tailed; p values were adjusted using the Holm-Bonferroni correction for pairwise comparisons; p values in bold indicate a statistical significance at the .05 level; N, observable entheses; n, affected entheses

Table 16 . Frequency of young and mature adult individuals (YMA) with at least one enthesis affected by changes in the Hungarian groups with (RD) and without riding deposit (NRD) and the comparison group from Lisbon (LIS), and statistical comparison

 16

		RD YMA	NRD YMA			LIS YMA		p
		N n	n/N	N	n	n/N	N	n	n/N	exact
	Left	7 5	71% 23 19	83% 29 15	52%	.053
	Right	7 6	86% 27 18	67% 29 14	48%	.141
	Left+Right	7 6	86% 25 21	84% 28 18	64%	.211

Fisher's exact test, two-tailed; N, number of observable individuals; n, number of individuals with at least one enthesis affected by changes

Table 17 . Frequency of entheseal changes observed in young and mature adult individuals (YMA) from the Hungarian groups with (RD) and without riding deposit (NRD) and the comparison group from Lisbon (LIS), and statistical comparison

 17

	Enthesis	RD YMA N n n/N	NRD YMA N n n/N	LIS YMA N n n/N	p exact	p exact adjusted RD-NRD RD-LIS NRD-LIS
	COX E1 L	6	3 50%	21	5 24%	24	3 13%	.101	-	-	-
	COX E1 R	5	1 20%	22	4 18%	27	3 11%	.627	-	-	-
	COX E1 L+R	11	4 36%	43	9 21%	51	6 12%	.125	-	-	-
	COX E2 L	6	1 17%	20	5 25%	27	4 15%	.776	-	-	-
	COX E2 R	5	1 20%	22	5 23%	27	6 22%	1	-	-	-
	COX E2 L+R	11	2 18%	42	10 24%	54	10 19%	.882	-	-	-
	FEM E1 L	4	0 0%	17	1 6%	28	1 4%	1	-	-	-
	FEM E1 R	4	0 0%	21	1 5%	26	0 0%	.490	-	-	-
	FEM E1 L+R	8	0 0%	38	2 5%	54	1 2%	.664	-	-	-
	FEM E2 L	4	0 0%	15	1 7%	26	3 12%	1	-	-	-
	FEM E2 R	4	0 0%	18	1 6%	27	1 4%	1	-	-	-
	FEM E2 L+R	8	0 0%	33	2 6%	53	4 8%	1	-	-	-
	FEM E3 L	5	1 20%	22	8 36%	29	7 24%	.555	-	-	-
	FEM E3 R	7	2 29%	21	8 38%	29	5 17%	.280	-	-	-
	FEM E3 L+R	12	3 25%	43	16 37%	58	12 21%	.166	-	-	-
	FEM E4 L	5	0 0%	16	2 13%	29	4 14%	1	-	-	-
	FEM E4 R	6	0 0%	25	2 8%	29	2 7%	1	-	-	-
	FEM E4 L+R	11	0 0%	41	4 10%	58	6 10%	.790	-	-	-
	FEM E5 L	5	0 0%	21	4 19%	27	2 7%	.435	-	-	-
	FEM E5 R	5	1 20%	26	5 19%	28	3 11%	.552	-	-	-
	FEM E5 L+R	10	1 10%	47	9 19%	55	5 9%	.317	-	-	-
	FEM E6 L	6	0 0%	24	4 17%	28	2 7%	.449	-	-	-
	FEM E6 R	5	0 0%	25	2 8%	28	2 7%	1	-	-	-
	FEM E6 L+R	11	0 0%	49	6 12%	56	4 7%	.542	-	-	-
	FEM E7 L	5	2 40%	17	2 12%	26	2 8%	.198	-	-	-
	FEM E7 R	3	1 33%	22	3 14%	29	1 3%	.138	-	-	-
	FEM E7 L+R	8	3 38%	39	5 13%	55	3 5%	.027	.245	.070	.269
	PAT E1 L	5	0 0%	13	3 23%	19	3 16%	.707	-	-	-
	PAT E1 R	4	1 25%	15	4 27%	21	2 10%	.312	-	-	-
	PAT E1 L+R	9	1 11%	28	7 25%	40	5 13%	.392	-	-	-
	TIB E1 L	7	0 0%	21	0 0%	23	3 13%	.351	-	-	-
	TIB E1 R	6	0 0%	24	0 0%	26	5 19%	.070	-	-	-
	TIB E1 L+R	13	0 0%	45	0 0%	49	8 16%	.004	1	.372	.018
	TIB E2 L	7	0 0%	24	3 13%	28	2 7%	.819	-	-	-
	TIB E2 R	6	0 0%	26	3 12%	28	3 11%	1	-	-	-
	TIB E2 L+R	13	0 0%	50	6 12%	56	5 9%	.606	-	-	-
	CAL E1 L	5	3 60%	18	14 78%	22	2 9% < .001	.576	.060 < .001
	CAL E1 R	4	2 50%	21	13 62%	25	3 12%	.001	1	.253	.002
	CAL E1 L+R	9	5 56%	39	27 69%	47	5 11% < .001	.457	.012 < .001

Fisher's exact test, two-tailed; p values were adjusted using the Holm-Bonferroni correction for pairwise comparisons; p values in bold indicate a statistical significance at the .05 level; N, number of observable entheses; n, number of affected entheses; see Table

9

for the entheses' codes

Table 18 . Frequency of all entheseal changes observed in individuals in all adult age categories from the Hungarian groups with (RD) and without riding deposit (NRD) and the comparison group from Lisbon (LIS), and statistical comparison

 18

			RD all		NRD all		LIS all	p	p exact adjusted
		N	n n/N	N	n n/N	N	n n/N	exact	RD-NRD RD-LIS NRD-LIS
	Left	168 48 29% 449 165 37% 489	91 19% < .001	.058	.017	< .001
	Right	158 43 27% 490 158 32% 487	74 15% < .001	.277	.002	< .001
	Left+Right	326 91 28% 939 323 34% 976 165 17% < .001	.034	< .001	< .001

Fisher's exact test, two-tailed; p values were adjusted using the Holm-Bonferroni correction for pairwise comparisons; p values in bold indicate a statistical significance at the .05 level; N, number of observable entheses; n, number of entheses affected

Table 19 . Frequency of individuals in all adult age categories with at least one enthesis affected by changes in the Hungarian groups with (RD) and without riding deposit (NRD) and the comparison group from Lisbon (LIS), and statistical comparison

 19 Pairwise comparisons with corrected p values revealed that there were significantly more individuals affected by EC in the NRD group (90%) compared to the LIS group (64%) considering only EC on the left side (p adjusted = .024), and more in the RD group (94%)

			RD all		NRD all		LIS all	p	p exact adjusted
		N	n n/N	N	n n/N	N	n n/N	exact	RD-NRD	RD-LIS	NRD-LIS
	Left	17 14 82% 41 37 90% 42 27 64%	.012	.444	.444	.024
	Right	17 16 94% 45 36 80% 40 24 60%	.016	.260	.034	.115
	Left+Right	17 16 94% 44 40 91% 41 30 73%	.043	1	.177	.137

Fisher's exact test, two-tailed; p values were adjusted using the Holm-Bonferroni correction for pairwise comparisons; p values in bold indicate a statistical significance at the .05 level; N, number of observable individuals; n, number of individuals with at least one enthesis affected by changes

Table 20 . Frequency of entheseal changes observed in individuals in all adult age categories from the Hungarian groups with (RD) and without riding deposit (NRD) and the comparison group from Lisbon (LIS), and statistical comparison

 20

	Enthesis	N	RD all n n/N	NRD all N n n/N	N	LIS all n n/N	p exact	p exact adjusted RD-NRD RD-LIS NRD-LIS
	COX E1 L	14	7 50%	38	17 45%	36	8 22%	.062	-	-	-
	COX E1 R	13	3 23%	38	13 34%	37	7 19%	.345	-	-	-
	COX E1 L+R	27	10 37%	76	30 39%	73	15 21%	.033	1	.238	.039
	COX E2 L	15	6 40%	36	20 56%	40	13 33%	.131	-	-	-
	COX E2 R	13	5 38%	39	21 54%	38	13 34%	.208	-	-	-
	COX E2 L+R	28	11 39%	75	41 55%	78	26 33%	.025	.378	.646	.028
	FEM E1 L	11	0 0%	30	6 20%	40	4 10%	.225	-	-	-
	FEM E1 R	10	0 0%	37	5 14%	37	1 3%	.211	-	-	-
	FEM E1 L+R	21	0 0%	67	11 16%	77	5 6%	.047	.179	.582	.179
	FEM E2 L	6	0 0%	29	6 21%	38	8 21%	.739	-	-	-
	FEM E2 R	8	0 0%	31	5 16%	37	3 8%	.470	-	-	-
	FEM E2 L+R	14	0 0%	60	11 18%	75	11 15%	.233	-	-	-
	FEM E3 L	13	6 46%	39	18 46%	41	12 29%	.263	-	-	-
	FEM E3 R	13	8 62%	38	18 47%	40	9 23%	.014	.523	.047	.063
	FEM E3 L+R	26	14 54%	77	36 47%	81	21 26%	.006	.651	.030	.024
	FEM E4 L	12	4 33%	32	11 34%	41	9 22%	.428	-	-	-
	FEM E4 R	15	3 20%	40	10 25%	40	5 13%	.411	-	-	-
	FEM E4 L+R	27	7 26%	72	21 29%	81	14 17%	.201	-	-	-
	FEM E5 L	15	3 20%	37	15 41%	38	7 18%	.094	-	-	-
	FEM E5 R	11	3 27%	42	13 31%	39	10 26%	.897	-	-	-
	FEM E5 L+R	26	6 23%	79	28 35%	77	17 22%	.150	-	-	-
	FEM E6 L	16	3 19%	40	12 30%	38	5 13%	.197	-	-	-
	FEM E6 R	14	3 21%	42	11 26%	39	4 10%	.179	-	-	-
	FEM E6 L+R	30	6 20%	82	23 28%	77	9 12%	.034	.704	.704	.032
	FEM E7 L	10	3 30%	30	6 20%	38	2 5%	.061	-	-	-
	FEM E7 R	10	4 40%	34	8 24%	40	1 3%	.002	.422	.012	.019
	FEM E7 L+R	20	7 35%	64	14 22%	78	3 4% < .001	.250	.001	.003
	PAT E1 L	10	3 30%	23	8 35%	30	9 30%	.934	-	-	-
	PAT E1 R	10	3 30%	28	10 36%	32	5 16%	.216	-	-	-
	PAT E1 L+R	20	6 30%	51	18 35%	62	14 23%	.312	-	-	-
	TIB E1 L	15	0 0%	38	3 8%	35	5 14%	.328	-	-	-
	TIB E1 R	14	0 0%	40	5 13%	36	8 22%	.137	-	-	-
	TIB E1 L+R	29	0 0%	78	8 10%	71	13 18%	.021	.209	.053	.238
	TIB E2 L	17	3 18%	42	12 29%	40	4 10%	.105	-	-	-
	TIB E2 R	16	2 13%	44	10 23%	38	3 8%	.187	-	-	-
	TIB E2 L+R	33	5 15%	86	22 26%	78	7 9%	.018	.656	.656	.021
	CAL E1 L	14	10 71%	35	31 89%	34	5 15% < .001	.202	.001 < .001
	CAL E1 R	11	9 82%	37	29 78%	34	5 15% < .001	1 < .001 < .001
	CAL E1 L+R	25	19 76%	72	60 83%	68	10 15% < .001	.551 < .001 < .001

Fisher's exact test, two-tailed; p values were adjusted using the Holm-Bonferroni correction for pairwise comparisons; p values in bold indicate a statistical significance at the .05 level; N, number of observable entheses; n, number of affected entheses; see Table

9

for the entheses' codes

Table 21 . Bilateral asymmetry for the entheseal changes observed on paired bones in individuals in all adult age categories from the Hungarian groups with (RD) and without riding deposit (NRD) and the comparison group from Lisbon (LIS), and statistical comparison

 21

	Enthesis	Asymmetry	n	RD	n/N	NRD n	n/N	n	LIS	n/N	p exact
		R = L	9		90%	30	94%	29		91%
	COX E1	R > L L > R	0 1		0% 10%	0 2	0% 6%	2 1		6% 3%	.634
		N pairs	10			32		32
		R = L	11		92%	31	94%	27		77%
	COX E2	R > L L > R	1 0		8% 0%	1 1	3% 3%	5 3		14% 9%	.349
		N pairs	12			33		35
		R = L	6		100%	26	93%	34		97%
	FEM E1	R > L L > R	0 0		0% 0%	0 2	0% 7%	0 1		0% 3%	.682
		N pairs	6			28		35
		R = L	3		100%	21	91%	32		94%
	FEM E2	R > L L > R	0 0		0% 0%	2 0	9% 0%	0 2		0% 6%	.305
		N pairs	3			23		34
		R = L	8		80%	24	73%	31		82%
	FEM E3	R > L L > R	2 0		20% 0%	5 4	15% 12%	3 4		8% 11%	.680
		N pairs	10			33		38

Table 22 . Frequency of all joint changes observed in the young and mature adult individuals (YMA) from the Hungarian groups with (RD) and without riding deposit (NRD) and the comparison group from Lisbon (LIS), and statistical comparison

 22

		RD YMA	NRD YMA	LIS YMA	p	p exact adjusted
		N n n/N	N	n n/N	N	n n/N	exact	RD-NRD RD-LIS NRD-LIS
	Left	24 1 4%	87 11 13% 118 19 16%	.316	-	-	-
	Right	21 1 5%	93	9 10% 120 21 18%	.165	-	-	-
	Left+Right	45 2 4% 180 20 11% 238 40 17%	.044	.263	.113	.242

Fisher's exact test, two-tailed; p values were adjusted using the Holm-Bonferroni correction for pairwise comparisons; p values in bold indicate a statistical significance at the .05 level; N, number of observable joints; n, number of affected joints

Table 23 . Frequency of young and mature adult individuals (YMA) with at least one joint affected by changes in the Hungarian groups with (RD) and without riding deposit (NRD) and the comparison group from Lisbon (LIS), and statistical comparison

 23

		RD YMA	NRD YMA		LIS YMA		p
		N n	n/N	N n	n/N	N	n	n/N	exact
	Left	7 1	14% 24 6	25% 30 11	37%	.447
	Right	6 1	17% 26 6	23% 30 12	40%	.335
	Left+Right	7 2	29% 24 9	38% 29 15	52%	.493
	Fisher's exact test, two-tailed; N, number of observable individuals; n, number of individuals
	with at least one joint affected by changes

Table 24 . Frequency of joint changes observed in young and mature adult individuals (YMA) from the Hungarian groups with (RD) and without riding deposit (NRD) and the comparison group from Lisbon (LIS), and statistical comparison

 24

	Joint	RD YMA N n n/N	NRD YMA N n n/N	LIS YMA N n n/N	p exact
	Acetabulofemoral L	7	1 14%	24	5 21%	30	7 23%	1
	Acetabulofemoral R	6	1 17%	24	4 17%	31	8 26%	.807
	Acetabulofemoral L+R	13	2 15%	48	9 19%	61	15 25%	.729
	Patellofemoral L	5	0 0%	20	1 5%	30	5 17%	.528
	Patellofemoral R	5	0 0%	19	1 5%	30	5 17%	.532
	Patellofemoral L+R	10	0 0%	39	2 5%	60	10 17%	.151
	Tibiofemoral L	5	0 0%	20	4 20%	30	4 13%	.627
	Tibiofemoral R	4	0 0%	24	3 13%	30	5 17%	.848
	Tibiofemoral L+R	9	0 0%	44	7 16%	60	9 15%	.603
	Talocrural L	7	0 0%	23	1 4%	28	3 11%	.775
	Talocrural R	6	0 0%	26	1 4%	29	3 10%	.747
	Talocrural L+R	13	0 0%	49	2 4%	57	6 11%	.419

Fisher's exact test, two-tailed; N, number of observable joints; n, number of affected joints

Table 25 . Frequency of perifoveal osteophytes (femoral head) observed in young and mature adult individuals (YMA) from the Hungarian groups with (RD) and without riding deposit (NRD) and the comparison group from Lisbon (LIS), and statistical comparison

 25

	Site	RD YMA N n n/N	NRD YMA N n n/N	LIS YMA N n n/N	p exact
	Fovea capitis L	6	1 17%	19	7 37%	30	8 27%	.687
	Fovea capitis R	3	1 33%	20	8 40%	30	7 23%	.438
	Fovea capitis L+R	9	2 22%	39	15 38%	60	15 25%	.322

Fisher's exact test, two-tailed; N, number of observable joints; n, number of affected joints

I.B.1.b.Individuals in all adult age categories

A total of 774 joints (as presented in Chapter 2, and apart from the fovea capitis case) could be observed in individuals in all adult age categories, and 193 (25%) showed changes. There was no significant difference between sides and the frequency of joint changes was approximately equivalent between groups (Table

26

).

Table 26 . Frequency of joint changes observed in individuals in all adult age categories from the Hungarian groups with (RD) and without riding deposit (NRD) and the comparison group from Lisbon (LIS), and statistical comparison

 26

			RD all	NRD all		LIS all	p
		N	n n/N	N	n n/N	N	n n/N	exact
	Left	57 14 25% 150 37 25% 178 44 25%	1
	Right	58 15 26% 159 44 28% 172 39 23%	.576
	Left+Right	115 29 25% 309 81 26% 350 83 24%	.760

Fisher's exact test, two-tailed; N, number of observable joints; n, number of affected joints Those joint changes concerned a total of 65 individuals in all adult age categories (63%)

Table 27 . Frequency of individuals in all adult age categories with at least one joint affected by changes in the Hungarian groups with (RD) and without riding deposit (NRD) and the comparison group from Lisbon (LIS), and statistical comparison

 27

		N	RD all n n/N	N	NRD all n n/N	N	LIS all n n/N	p exact
	Left	16	9 56% 42 21 50% 45 22 49%	.930
	Right	16	8 50% 45 25 56% 43 22 51%	.897
	Left+Right	16 10 63% 43 28 65% 44 27 61%	.961
	Fisher's exact test, two-tailed; N, number of observable individuals; n, number of individuals
	with at least one joint affected by changes

Table 28 . Frequency of joint changes observed in individuals in all adult age categories from the Hungarian groups with (RD) and without riding deposit (NRD) and the comparison group from Lisbon (LIS), and statistical comparison

 28

	Joint	N	RD all n n/N	NRD all N n n/N	N	LIS all n n/N	p exact
	Acetabulofemoral L	15	6 40%	42	18 43%	45	16 36%	.762
	Acetabulofemoral R	15	5 33%	43	20 47%	44	13 30%	.245
	Acetabulofemoral L+R	30	11 37%	85	38 45%	89	29 33%	.260
	Patellofemoral L	13	2 15%	34	6 18%	45	12 27%	.574
	Patellofemoral R	14	3 21%	34	7 21%	43	11 26%	.943
	Patellofemoral L+R	27	5 19%	68	13 19%	88	23 26%	.529
	Tibiofemoral L	12	5 42%	34	10 29%	45	9 20%	.241
	Tibiofemoral R	14	6 43%	39	13 33%	43	10 23%	.290
	Tibiofemoral L+R	26	11 42%	73	23 32%	88	19 22%	.088
	Talocrural L	17	1 6%	40	3 8%	43	7 16%	.396
	Talocrural R	15	1 7%	43	4 9%	42	5 12%	.907
	Talocrural L+R	32	2 6%	83	7 8%	85	12 14%	.429

Fisher's exact test, two-tailed; N, number of observable joints; n, number of affected joints

Table 29 . Frequency of perifoveal osteophytes (femoral head) observed in individuals in all adult age categories from the Hungarian groups with (RD) and without riding deposit (NRD) and the comparison group from Lisbon (LIS), and statistical comparison

 29

	Joint	N	RD all n n/N	NRD all N n n/N	N	LIS all n n/N	p exact	p exact adjusted RD-NRD RD-LIS NRD-LIS
	Fovea L	12	6 50%	32	15 47%	44	15 34%	.418	-	-	-
	Fovea R	9	6 67%	34	20 59%	43	15 35%	.056	-	-	-
	Fovea L+R	21	12 57%	66	35 53%	87	30 34%	.032	.805	.160	.094

Fisher's exact test, two-tailed; p values were adjusted using the Holm-Bonferroni correction for pairwise comparisons; p values in bold indicate a statistical significance at the .05 level; N, observable joints; n, affected joints

Frequency of joint changes observed in individuals in all adult age categories from the Hungarian groups with (RD) and without (NRD) riding deposit and the comparison group from Lisbon (LIS)

	50%
	45%
	40%
	35%
	30%
	25%
	20%
	15%
	10%
	5%
	0%
	RD NRD LIS
	Figure 27.

Table 30 . Bilateral asymmetry for the joint changes observed in individuals in all adult age categories from the Hungarian groups with (RD) and without riding deposit (NRD) and the comparison group from Lisbon (LIS), and statistical comparison

 30

	Joint	Bilateral asymmetry	RD all n	n/N	NRD all n	n/N	LIS all n	n/N	p exact
		R = L	11		79%	34	85%	36	84%
	Acetabulofemoral	R > L L > R	1 2		7% 14%	4 2	10% 5%	3 4	7% 9%	.797
		N pairs	14			40		43
		R = L	11		92%	26	90%	37	88%
	Patellofemoral	R > L L > R	1 0		8% 0%	2 1	7% 3%	3 2	7% 5%	1
		N pairs	12			29		42
		R = L	11	100%	26	84%	35	83%
	Tibiofemoral	R > L L > R	0 0		0% 0%	4 1	13% 3%	5 2	12% 5%	.853
		N pairs	11			31		42
		R = L	15	100%	35	92%	37	93%
	Talocrural	R > L L > R	0 0		0% 0%	2 1	5% 3%	1 2	3% 5%	.949
		N pairs	15			38		40

Fisher's exact test, two-sided; L, left side; R, right side; Asymmetry calculated as right side minus left side; R = L, equal scores; R > L, right score higher; L > R, left score higher

Table 31 . Bilateral asymmetry for the perifoveal osteophytes (femoral head) observed in individuals in all adult age categories from the Hungarian groups with (RD) and without riding deposit (NRD) and the comparison group from Lisbon (LIS), and statistical comparison

 31

	Site	Bilateral asymmetry	RD all n	n/N	NRD all n	n/N	LIS all n	n/N	p exact
		R = L	8	89%	24	89%	36	88%
	Fovea capitis	R > L L > R	1 0	11% 0%	3 0	11% 0%	3 2	7% 5%	.782
		N pairs	9		27		41

Fisher's exact test, two-sided; L, left side; R, right side; Asymmetry calculated as right side minus left side; R = L, equal scores; R > L, right score higher; L > R, left score higher

Table 32 . Frequency of all morphological variants of the femur in the Hungarian groups with (RD) and without riding deposit (NRD) and the comparison group from Lisbon (LIS), and statistical comparison

 32

			RD		NRD		LIS	p	p exact adjusted
		N	n n/N	N	n n/N	N	n n/N	exact	RD-NRD RD-LIS NRD-LIS
	Left	77 31 40% 203	59 29% 251	57 23%	.010	.172	.010	.172
	Right	65 21 32% 238	76 32% 241	51 21%	.017	1	.140	.029
	Left+Right	142 52 37% 441 135 31% 492 108 22% < .001	.215	.002	.006

Fisher's exact test, two-tailed; p values were adjusted using the Holm-Bonferroni correction for pairwise comparisons; p values in bold indicate a statistical significance at the .05 level; N, number of observable sites; n, number of bone sites with a morphological variant

Table 33 . Frequency of individuals with at least one morphological variant on the femur in the Hungarian groups with (RD) and without riding deposit (NRD) and the comparison group from Lisbon (LIS), and statistical comparison

 33

		N	RD n	n/N	N	NRD n n/N N	LIS n n/N	p exact
	Left	15 15 100% 39 34 87% 44 41 93%	.315
	Right	13 11	85% 43 40 93% 42 39 93%	.681
	Left+Right	15 15 100% 46 43 93% 46 43 93%	.739

Fisher's exact test, two-tailed; N, number of observable individuals; n, number of individuals with at least one morphological variant

Table 34 . Frequency of morphological variants of the femur in the Hungarian groups with (RD) and without riding deposit (NRD) and the comparison group from Lisbon (LIS), and statistical comparison

 34

	Morphological		RD		NRD		LIS	p	p exact adjusted
	variant	N	n n/N	N	n n/N	N	n n/N	exact	RD-NRD RD-LIS NRD-LIS
	FEM V1 L	11	6 55%	34	5 15%	43	7 16%	.022	.043	.043	1
	FEM V1 R	9	3 33%	39	11 28%	42	6 14%	.202	-	-	-
	FEM V1 L+R	20	9 45%	73	16 22%	85	13 15%	.018	.309	.019	.099
	FEM V2 L	13	7 54%	36	27 75%	43	36 84%	.098	-	-	-
	FEM V2 R	9	8 89%	41	27 66%	42	33 79%	.266	-	-	-
	FEM V2 L+R	22	15 68%	77	54 70%	85	69 81%	.203	-	-	-
	FEM V3 L	13	2 15%	33	3 9%	34	3 9%	.777	-	-	-
	FEM V3 R	9	0 0%	39	5 13%	31	2 6%	.527	-	-	-
	FEM V3 L+R	22	2 9%	72	8 11%	65	5 8%	.869	-	-	-
	FEM V4 L	10	2 20%	26	2 8%	44	4 9%	.510	-	-	-
	FEM V4 R	13	1 8%	37	8 22%	43	3 7%	.162	-	-	-
	FEM V4 L+R	23	3 13%	63	10 16%	87	7 8%	.315	-	-	-
	FEM V5 L	15	10 67%	33	16 48%	44	5 11% < .001	.351 < .001	.001
	FEM V5 R	12	8 67%	39	19 49%	41	5 12% < .001	.335	.001	.001
	FEM V5 L+R	27	18 67%	72	35 49%	85	10 12% < .001	.120 < .001 < .001
	FEM V6 L	15	4 27%	41	6 15%	43	2 5%	.052	-	-	-
	FEM V6 R	13	1 8%	43	6 14%	42	2 5%	.390	-	-	-
	FEM V6 L+R	28	5 18%	84	12 14%	85	4 5%	.034	.762	.115	.115

Fisher's exact test, two-tailed; p values were adjusted using the Holm-Bonferroni correction for pairwise comparisons; p values in bold indicate a statistical significance at the .05 level; see Table

11

for the variants' codes; N, number of observable sites; n, number of sites with a morphological variant

Table 35 . Bilateral asymmetry for the morphological variants of the femur in the Hungarian groups with (RD) and without riding deposit (NRD) and the comparison group from Lisbon (LIS), and statistical comparison

 35

	Morphological	Bilateral	RD		NRD		LIS		p
	variant	asymmetry	n	n/N	n	n/N	n	n/N	exact
		R = L	7 100%	29	91%		97%
	FEM V1	R > L L > R	0 0	0% 0%	3 0	9% 0%		0% 3%	.272
		N pairs	7		32

Table 36 . Frequency of individuals with at least one vertebra affected by a Schmorl's node in the Hungarian groups with (RD) and without riding deposit (NRD) and the comparison group from Lisbon (LIS), and statistical comparison

 36

Table 37 . Frequency of Schmorl's nodes by size on the thoracic (T), lumbar (L), and the first sacral (S) vertebrae in the Hungarian groups with (RD) and without riding deposit (NRD) and the comparison group from Lisbon (LIS), and statistical comparison taking size into account

 37

	Vertebrae	N RD NRD LIS	RD n n/N	Small nodes NRD n n/N	LIS n n/N	RD n n/N	Large nodes NRD n n/N	LIS n n/N	RD n n/N	All nodes NRD n n/N	LIS n n/N	p exact	p exact adjusted RD-NRD RD-LIS NRD-LIS
	T1	11	37	44	0	0%	0	0%	0	0%	0	0%	0	0%	0	0%	0	0%	0	0%	0%	-	-	-	-
	T2	10	36	45	0	0%	1	3%	0	0%	0	0%	0	0%	0	0%	0	0%	1	3%	0%	.505	-	-	-
	T3	8	35	43	0	0%	1	3%	0	0%	0	0%	0	0%	0	0%	0	0%	1	3%	0%	.500	-	-	-
	T4	8	34	44	0	0%	4 12%	1	2%	0	0%	1	3%	0	0%	0	0%	5 15%	2%	.250	-	-	-
	T5	9	33	44	1 11%	8 24%	5 11%	0	0%	1	3%	0	0%	1 11%	9 27%	11%	.282	-	-	-
	T6	10	34	44	3 30%	9 26%	6 14%	1 10%	4 12%	2	5%	4 40% 13 38%	18%	.234	-	-	-
	T7	11	35	43	3 27%	11 31%	17 40%	1	9%	6 17%	2	5%	4 36% 17 49% 44%	.441	-	-	-
	T8	11	33	45	6 55%	18 55%	23 51%	1	9%	5 15%	3	7%	7 64% 23 70% 58%	.701	-	-	-
	T9	11	34	45	5 45%	16 47%	21 47%	1	9%	6 18%	3	7%	6 55% 22 65% 53%	.592	-	-	-
	T10	11	35	45	4 36%	15 43%	16 36%	3 27%	7 20%	4	9%	7 64% 22 63% 44%	.291	-	-	-
	T11	11	33	45	5 45%	10 30%	19 42%	2 18%	10 30%	3	7%	7 64% 20 61% 49%	.080	-	-	-
	T12	9	32	45	4 44%	12 38%	15 33%	1 11%	7 22%	1	2%	5 56% 19 59% 36%	.040	.893	.481	.032
	L1	10	32	43	6 60%	10 31%	9 21%	0	0%	6 19%	1	2%	6 60% 16 50% 23%	.009	.170	.077	.053
	L2	12	32	43	3 25%	11 34%	11 26%	1	8%	2	6%	0	0%	4 33% 13 41% 26%	.287	-	-	-
	L3	12	34	44	2 17%	11 32%	7 16%	1	8%	3	9%	1	2%	3 25% 14 41%	18%	.178	-	-	-
	L4	10	34	46	1 10%	8 24%	4	9%	0	0%	1	3%	0	0%	1 10%	9 26%	9%	.179	-	-	-
	L5	9	31	46	0	0%	3 10%	3	7%	0	0%	0	0%	0	0%	0	0%	3 10%	7%	.839	-	-	-
	S1	14	34	43	0	0%	2	6%	0	0%	0	0%	0	0%	0	0%	0	0%	2	6%	0%	.275	-	-	-
	Total T1-T6	56 209 264	4	7%	23 11%	12	5%	1	2%	6	3%	2	1%	5	9% 29 14%	5%	.022	.709	.709	.014
	Total T7-T12 64 202 268	27 42%	82 41% 111 41%	9 14%	41 20%	16	6% 36 56% 123 61% 47% < .001	.555	.152 < .001
	Total T	120 411 532	31 26% 105 26% 123 23%	10	8%	47 11%	18	3% 41 34% 152 37% 27% < .001	.654	.082 < .001
	Total L+S1	67 197 265	12 18%	45 23%	34 13%	2	3%	12	6%	2	1% 14 21% 57 29% 14% < .001	.421	.227 < .001
	Total All	187 608 797	43 23% 150 25% 157 20%	12	6%	59 10%	20	3% 55 29% 209 34% 22% < .001	.312	.031 < .001
	Fisher's exact test, two-tailed; p values were adjusted using the Holm-Bonferroni correction for pairwise comparisons; p values in bold indicate a statistical significance at the .05 level;
	comparisons were performed including the differences of size of Schmorl's nodes (absence, small SN, large SN); N, number of observable vertebrae; n, number of vertebrae affected by SN

Table 37 )

 37

								All nodes
	80%
	70%
	60%
	50%
	40%
	30%
	20%
	10%
	0%
	T1	T2	T3	T4	T5	T6	T7	T8	T9 T10 T11 T12 L1	L2	L3	L4	L5	S1
								RD	NRD	LIS

Table 37 )

 37

			All nodes
	70%
	60%
	50%
	40%
	30%
	20%
	10%
	0%
	Total T1-T6	Total T7-T12	Total T	Total L+S1	Total All
			RD NRD LIS

Table 38 . Frequency and distribution of fractures in the Hungarian groups with (RD) and without riding deposit (NRD) and the comparison group from Lisbon (LIS), and statistical comparison

 38

	Bone(s)/region	N	RD	n n/N	N	NRD n n/N	N	LIS	n n/N	p exact	p exact adjusted RD-NRD RD-LIS NRD-LIS
	Head	15		0 0%	43	0 0%	46		0 0%	-	-	-	-
	Clavicle	17		4 24%	49	3 6%	45		0 0%	.003	.133	.013	.243
	Scapula	15		1 7%	44	1 2%	46		0 0%	.140	-	-	-
	Humerus	17		1 6%	48	0 0%	47		1 2%	.150	-	-	-
	Radius, Ulna	17		1 6%	49	2 4%	46		1 2%	.804	-	-	-
	Carpal bones	5		0 0%	20	0 0%	21		1 5%	1	-	-	-
	Metacarpals, HPH 16		1 6%	46	7 15%	41		3 7%	.519	-	-	-
	Upper limb	17		6 35%	50	12 24%	45		6 13%	.131	-	-	-
	Thorax (ribs)	11		1 9%	35	3 9%	44		5 11%	1	-	-	-
	Sacrum	14		0 0%	40	0 0%	46		0 0%	-	-	-	-
	Coxal bone	17		0 0%	49	0 0%	47		1 2%	.566	-	-	-
	Femur	17		0 0%	50	2 4%	47		1 2%	1	-	-	-
	Patella	15		0 0%	41	0 0%	39		0 0%	-	-	-	-
	Tibia, Fibula	17		0 0%	49	3 6%	47		2 4%	.846	-	-	-
	Tarsal bones	14		0 0%	37	0 0%	44		0 0%	-	-	-	-
	Metatarsals, FPH	13		0 0%	42	1 2%	43		1 2%	1	-	-	-
	Lower limb	17		0 0%	50	5 10%	47		4 9%	.572	-	-	-
	All	17		7 41%	50	17 34%	47	14 30%	.716	-	-	-

Fisher's exact test, two-tailed; p values were adjusted using the Holm-Bonferroni correction for pairwise comparisons; p values in bold indicate a statistical significance at the .05 level; N, number of observable individuals; n, number of individuals affected by at least one fracture; HPH, hand phalanges; FPH, foot phalanges Figure 32. Distribution of fractures in the Hungarian groups with (RD) and without riding deposit (NRD), and the comparison group from Lisbon (LIS). * indicates statistically significant differences between groups (see Table 38

)

*

Table 39 . Interobserver (A-B) and intraobserver (A1-A2) agreement in the measurement of the maximum diameters of the acetabulum (n = 30) Observer A -Observer B Observer A1 -Observer A2 Vertical diameter Horizontal diameter Vertical diameter Horizontal diameter Mean of each series (mm

 39

	)	57.5 (A) 57.8 (B)	56.1 (A) 55.0 (B)	57.6 (A1) 57.5 (A2)	56.1 (A1) 56.1 (A2)
	Mean difference (mm)	-0.3	1.1	0.2	-0.1
	Mean absolute difference (mm)	0.8	1.1	0.5	0.3
	Concordance correlation coefficient	.949	.911	.979	.993
	A concordance correlation coefficient close to 1 indicates a strong concordance between two series of values

Table 40 . Composition of the samples of observable acetabula in the Hungarian groups with (RD) and without riding deposit (NRD) and in the comparison group from Lisbon (LIS) Group N individuals Individuals with at least one observable acetabulum

 40

	Observable acetabula	Pairs of
	Left	Right	Total	observable acetabula

Table 41 . Summary statistics of the index of ovalization of the acetabulum in the Hungarian groups with (RD) and without riding deposit (NRD) and in the comparison groups from Lisbon (LIS)

 41

	Group	n L R L+R	L	Minimum R	L+R	L	Maximum R	L+R	L	Mean R	L+R	Standard deviation L R L+R
	RD	7 9 16 0.972 0.994 0.972 1.112 1.101 1.112 1.040 1.045 1.043 0.051 0.039 0.043
	NRD 24 28 52 0.951 0.974 0.951 1.071 1.065 1.071 1.011 1.020 1.016 0.031 0.027 0.029
	LIS	41 39 80 0.942 0.938 0.938 1.080 1.058 1.080 1.007 1.014 1.011 0.034 0.034 0.034
	n, number of coxal bones that could be measured; L, left side; R, right side

Table 42 . Statistical comparison for the index of ovalization of the acetabulum (IOA) between the Hungarian groups with (RD) and without riding deposit (NRD) and the comparison group from Lisbon (LIS) Index H (df = 2)

 42

			p value	RD-NRD	RD-LIS	NRD-LIS
			Monte Carlo	U	p exact adjusted	U	p exact adjusted	U	p exact adjusted
	IOA L	2.752	.257	-	-	-	-	-	-
	IOA R	4.183	.129	-	-	-	-	-	-
	IOA L+R	7.313	.025	262	.050	374	.024	1907.5	.424

Kruskal-Wallis H test with Monte Carlo estimate for an exact test based on 10000 sampled tables; Mann-Whitney U test, two-tailed; p values were adjusted using the Holm-Bonferroni correction for pairwise comparisons; p values in bold indicate a statistical significance at the .05 level; L, left side; R, right side

Table 43 . Summary statistics for the asymmetry of the index of ovalization of the acetabulum measured on paired coxae in the Hungarian groups with (RD) and without riding deposit (NRD) and in the comparison group from Lisbon (LIS), and statistical comparison

 43

	Group	n pairs	Minimum L R	Maximum L R	L	Mean	R	Standard deviation L R	Z	p exact
	RD	5 0.989 1.002 1.112 1.101 1.047 1.037 0.050 0.040	-.813	.500
	NRD	21 0.951 0.986 1.071 1.065 1.012 1.021 0.033 0.025 -1.704	.090
	LIS	35 0.942 0.938 1.066 1.058 1.005 1.014 0.034 0.033 -1.352	.180

Table 44 . Evaluation of the asymmetry (right minus left value) of the index of ovalization of the acetabulum on paired coxae in the Hungarian groups with (RD) and without riding deposit (NRD) and in the comparison group from Lisbon (LIS), and statistical comparison between groups

 44

	Group	n pairs	Minimum Maximum	Mean	Standard deviation	H (df = 2)	p value Monte Carlo
	RD	5	-0.039	0.013	-0.010	0.022
	NRD	21	-0.048	0.047	0.009	0.024	2.614	.276
	LIS	35	-0.044	0.086	0.009	0.031
	Kruskal-Wallis H test with Monte Carlo estimate for an exact test based on 10000 sampled tables

Table 45 . Summary statistics of the indices of shape and robusticity in the Hungarian groups with (RD) and without riding deposit (NRD) and in the comparison groups from Lisbon (LIS)

 45

	Index	n Min	RD Max	Mean SD n Min	NRD Max	Mean SD n Min	LIS Max	Mean SD
		L	12 18.60 22.05 20.34 0.90 36 17.81 21.95 20.23 1.07 43 17.18 22.88 19.75 1.18
	FEM I1	R	12 19.01 21.67 20.16 0.80 37 17.75 21.95 20.19 0.99 43 17.84 25.29 20.04 1.32
		L+R 24 18.60 22.05 20.25 0.84 73 17.75 21.95 20.21 1.02 86 17.18 25.29 19.89 1.25
		L	15 89.83 111.72 98.71 7.05 43 88.38 122.42 101.44 8.83 43 84.97 122.35 104.01 7.95
	FEM I2	R	14 88.41 115.86 101.93 7.93 44 87.16 121.94 102.41 7.92 43 89.04 117.15 105.72 6.25
		L+R 29 88.41 115.86 100.26 7.53 87 87.16 122.42 101.93 8.35 86 84.97 122.35 104.86 7.16
		L	15 74.02 101.89 87.41 7.06 42 73.63 107.48 86.78 7.18 43 76.22 100.78 91.67 6.00
	FEM I3	R	14 75.92 106.52 90.00 8.23 42 70.95 108.96 87.07 8.34 43 80.61 105.78 91.97 6.41
		L+R 29 74.02 106.52 88.66 7.62 84 70.95 108.96 86.92 7.73 86 76.22 105.78 91.82 6.17
		L	10 32.73 40.37 35.95 2.49 30 31.93 39.13 35.24 1.60 40 29.52 39.21 34.23 2.35
	FEM I4	R	9 31.03 41.00 35.61 2.69 34 30.22 39.02 34.70 1.96 42 28.93 38.13 33.72 2.14
		L+R 19 31.03 41.00 35.79 2.52 64 30.22 39.13 34.95 1.80 82 28.93 39.21 33.97 2.25
		L	8 21.11 24.47 22.24 1.21 34 20.07 23.65 21.69 0.91 43 18.50 23.78 20.47 1.17
	FEM I5	R	10 20.85 24.65 22.16 1.19 33 19.94 23.30 21.69 0.94 42 18.27 23.92 20.77 1.21
		L+R 18 20.85 24.65 22.20 1.16 67 19.94 23.65 21.69 0.92 85 18.27 23.92 20.62 1.19
		L	8 84.89 101.12 94.13 5.40 24 81.19 112.50 93.94 6.43 28 88.46 113.16 98.44 6.15
	PAT I1	R	8 81.19 102.27 93.09 6.58 28 82.68 102.13 92.73 5.32 32 88.25 109.73 96.94 6.13
		L+R 16 81.19 102.27 93.61 5.84 52 81.19 112.50 93.29 5.83 60 88.25 113.16 97.64 6.13
		L	16 20.06 24.42 21.62 1.16 39 19.77 24.70 21.71 1.29 43 18.83 25.15 21.43 1.52
	TIB I1	R	16 20.67 25.41 21.85 1.34 43 19.36 24.78 21.86 1.32 41 18.47 25.08 21.64 1.46
		L+R 32 20.06 25.41 21.74 1.24 82 19.36 24.78 21.79 1.30 84 18.47 25.15 21.53 1.49
		L	16 54.65 74.24 66.73 5.18 44 59.53 87.38 70.34 5.42 43 56.32 90.26 68.56 6.35
	TIB I2	R	16 57.88 72.46 65.71 4.04 45 58.55 88.13 69.66 5.59 42 56.20 80.89 67.35 5.30
		L+R 32 54.65 74.24 66.22 4.60 89 58.55 88.13 70.00 5.49 85 56.20 90.26 67.96 5.86
		L	8 8.56 11.56 10.37 1.00 18 7.63 12.73 10.20 1.37 29 7.71 11.96	9.90 1.20
	FIB I1	R	7 9.49 12.89 10.80 1.07 20 7.65 12.18 10.35 1.41 28 8.38 12.23 10.26 0.97
		L+R 15 8.56 12.89 10.57 1.02 38 7.63 12.73 10.28 1.38 57 7.71 12.23 10.08 1.09
		L	13 75.30 84.29 79.73 2.71 31 70.13 86.10 78.00 3.51 39 67.78 82.23 74.41 3.43
	TAL I1	R	13 75.63 83.23 79.61 2.35 36 71.67 86.89 77.93 3.56 41 69.57 84.39 74.98 3.94
		L+R 26 75.30 84.29 79.67 2.48 67 70.13 86.89 77.96 3.51 80 67.78 84.39 74.70 3.69
		L	14 56.94 69.08 60.86 3.47 34 54.30 62.73 58.70 2.37 39 52.93 76.34 57.65 3.77
	TAL I2	R	14 57.49 65.38 60.48 2.64 37 52.91 63.85 58.43 2.46 41 52.83 75.76 57.51 3.60
		L+R 28 56.94 69.08 60.67 3.03 71 52.91 63.85 58.56 2.40 80 52.83 76.34 57.58 3.66
		L	12 77.58 93.71 85.03 5.73 32 74.24 93.39 84.95 4.78 39 70.66 93.31 82.09 5.59
	TAL I3	R	15 74.12 91.72 82.30 4.63 38 74.37 94.03 83.30 4.77 41 75.14 93.00 81.96 4.86
		L+R 27 74.12 93.71 83.52 5.23 70 74.24 94.03 84.05 4.81 80 70.66 93.31 82.03 5.19
		L	12 48.80 60.27 52.47 2.88 32 47.41 56.55 52.83 2.21 39 45.85 56.99 51.18 2.95
	CAL I1	R	10 49.41 56.08 52.50 2.16 32 48.75 57.92 52.78 2.44 38 45.49 58.11 51.56 3.13
		L+R 22 48.80 60.27 52.48 2.52 64 47.41 57.92 52.80 2.31 77 45.49 58.11 51.37 3.03
		L	14 46.91 63.24 52.97 4.07 36 45.35 58.11 51.86 3.00 40 42.11 57.75 48.76 3.79
	CAL I2	R	11 47.56 58.23 52.70 3.12 36 45.35 57.75 51.77 3.10 40 42.35 57.97 48.77 3.83
		L+R 25 46.91 63.24 52.85 3.61 72 45.35 58.11 51.82 3.03 80 42.11 57.97 48.76 3.79
	n, number of calculated index values; Min, minimum; Max, maximum; SD, standard deviation; L, left side; R, right side

Table 46 . Statistical comparison for the indices of shape and robusticity in the Hungarian groups with (RD) and without riding deposit (NRD) and in the comparison groups from Lisbon (LIS)

 46

	Index		H (df = 2)	p value Monte Carlo	U	RD-NRD p exact adjusted	U	RD-LIS p exact adjusted	U	NRD-LIS p exact adjusted
		L	5.533	.057		-	-		-	-	-	-
	FEM I1	R	0.982	.615		-	-		-	-	-	-
		L+R	5.846	.050	874.0	.988	804.0	.199	2502.5	.083
		L	4.541	.100		-	-		-	-	-	-
	FEM I2	R	6.064	.047	304.0	.950	215.0	.227	673.5	.061
		L+R	9.849	.006	1118.0	.364	817.5	.016	2945.5	.031
		L	11.580	.003	285.5	.599	206.0	.077	534.5	.003
	FEM I3	R	8.165	.015	235.0	.543	246.5	.543	581.5	.013
		L+R	20.440	< .001	1054.5	.285	890.5	.042	2192.5	< .001
		L	6.358	.041	124.5	.436	126.0	.149	418.5	.092
	FEM I4	R	6.856	.029	121.0	.349	99.0	.075	527.5	.103
		L+R	13.771	.001	488.0	.196	446.5	.008	1870.5	.008
		L	25.076	< .001	101.0	.272	47.0	.001	294.5	< .001
	FEM I5	R	16.082	< .001	136.0	.416	83.0	.005	372.0	.001
		L+R	41.337	< .001	475.5	.173	255.0	< .001	1326.0	< .001
		L	7.272	.024	85.0	.648	73.0	.287	195.0	.027
	PAT I1	R	5.928	.049	99.0	.641	93.0	.493	288.0	.051
		L+R	12.702	.001	375.5	.564	330.5	.113	970.5	.001
		L	0.569	.756		-	-		-	-	-	-
	TIB I1	R	0.251	.888		-	-		-	-	-	-
		L+R	0.739	.694		-	-		-	-	-	-
		L	3.878	.145		-	-		-	-	-	-
	TIB I2	R	5.950	.050	216.0	.052	279.5	.331	760.0	.234
		L+R	9.684	.006	920.5	.008	1149.0	.199	3099.0	.079
		L	0.899	.647		-	-		-	-	-	-
	FIB I1	R	1.060	.600		-	-		-	-	-	-
		L+R	1.930	.378		-	-		-	-	-	-
		L	24.810	< .001	134.0	.085	55.0	< .001	284.0	< .001
	TAL I1	R	17.911	< .001	152.0	.064	95.0	.001	423.0	.002
		L+R	42.805	< .001	582.0	.013	287.5	< .001	1408.0	< .001
		L	13.973	.001	161.5	.084	101.0	.001	444.5	.030
	TAL I2	R	15.499	< .001	145.5	.031	92.0	< .001	548.5	.035
		L+R	29.315	< .001	617.5	.003	394.0	< .001	1969.5	.002
		L	5.366	.064		-	-		-	-	-	-
	TAL I3	R	1.648	.454		-	-		-	-	-	-
		L+R	6.298	.044	874.5	.574	898.5	.390	2149.5	.042
		L	5.920	.052		-	-		-	-	-	-
	CAL I1	R	3.212	.204		-	-		-	-	-	-
		L+R	8.663	.012	621.0	.415	680.5	.326	1771.5	.012
		L	17.043	< .001	217.0	.457	113.5	.001	386.5	.001
	CAL I2	R	16.836	< .001	170.0	.491	89.0	.004	375.5	.001
		L+R	33.513	< .001	771.5	.292	411.0	< .001	1534.5	< .001
	Kruskal-Wallis H test with Monte Carlo estimate for an exact test based on 10000 sampled tables; Mann-Whitney U test,

two-tailed; p values were adjusted using the Holm-Bonferroni correction for pairwise comparisons; p values in bold indicate a statistical significance at the .05 level; L, left side; R, right side

Table 47 . Summary statistics for the asymmetry of indices of shape and robusticity calculated from paired bones in the Hungarian groups with (RD) and without riding deposit (NRD) and in the comparison group from Lisbon (LIS)

 47

	Index		n Min	RD Max	Mean SD n Min	NRD Max	Mean	SD	n Min	LIS Max	Mean SD
	FEM I1	L R	10	18.60 22.05 20.26 0.96 19.01 21.67 20.21 0.88	30	17.81 21.95 20.20 1.13 17.75 21.95 20.24 1.06	40	17.18 22.88 19.81 1.19 17.84 22.20 19.89 1.06
	FEM I2	L R	13	89.83 111.72 99.31 7.15 88.41 115.86 102.81 7.51	40	88.38 122.42 101.83 8.97 87.16 121.94 102.86 8.09	40	84.97 122.35 103.70 8.03 89.04 117.15 105.94 6.42
	FEM I3	L R	12	74.02 101.89 87.67 7.92 75.92 106.52 90.45 8.79	37	73.63 107.48 86.83 7.01 70.95 108.96 87.29 8.48	40	76.22 100.69 91.61 5.97 80.61 105.78 91.94 6.42
	FEM I4	L R	7	32.73 40.37 36.40 2.57 31.03 41.00 35.84 3.06	24	31.93 38.47 35.24 1.53 31.69 39.02 34.92 1.88	38	29.52 39.21 34.29 2.39 28.93 38.13 33.54 2.06
	FEM I5	L R	6	21.11 24.47 22.28 1.34 20.85 24.65 22.23 1.47	27	20.07 23.57 21.67 0.91 20.00 23.26 21.71 0.91	39	18.50 23.78 20.52 1.17 18.27 23.92 20.64 1.13
	PAT I1	L R	5	84.89 98.77 93.06 5.99 81.19 102.27 92.35 8.26	16	81.19 98.01 91.62 5.19 82.68 98.14 91.31 5.03	26	88.46 113.16 98.76 6.15 88.25 109.73 97.78 6.30
	TIB I1	L R	15	20.06 24.42 21.62 1.20 20.67 25.41 21.92 1.36	36	19.77 24.70 21.74 1.34 20.00 24.78 22.03 1.30	38	18.83 25.15 21.46 1.41 18.47 25.08 21.61 1.35
	TIB I2	L R	15	54.65 74.24 67.11 5.13 57.88 72.46 65.57 4.14	42	59.53 87.38 70.32 5.47 58.55 88.13 69.74 5.67	39	56.32 80.33 68.11 5.57 56.20 80.89 67.67 5.20
	FIB I1	L R	3	9.88 10.63 10.15 0.41 10.14 11.20 10.63 0.53	11	7.63 11.63 10.18 1.43 7.65 12.10 10.38 1.39	20	7.86 11.96 10.01 1.19 8.38 12.23 10.23 0.99
	TAL I1	L R	12	75.30 84.29 79.52 2.72 77.08 83.23 79.94 2.11	27	70.13 86.10 78.05 3.68 71.67 86.89 78.08 3.44	36	67.78 82.23 74.36 3.41 69.57 83.27 74.98 3.61
	TAL I2	L R	13	56.94 65.52 60.23 2.64 57.49 65.38 60.25 2.60	29	54.30 62.73 58.69 2.50 52.91 63.85 58.31 2.47	36	52.93 76.34 57.52 3.89 52.83 75.76 57.57 3.63
	TAL I3	L R	12	77.58 93.71 85.03 5.73 74.12 91.72 82.77 5.08	28	74.24 93.39 85.04 4.82 75.75 94.03 84.38 4.65	36	70.66 93.31 81.80 5.53 75.14 93.00 81.93 4.85
	CAL I1	L R	8	50.25 54.21 52.13 1.42 49.41 56.08 52.59 2.14	22	47.41 56.25 52.51 2.18 49.40 56.51 52.69 2.09	35	46.00 56.99 51.26 2.96 45.49 58.11 51.49 3.26
	CAL I2	L R	9	46.91 57.69 52.41 3.25 47.56 58.23 52.80 3.38	29	45.35 58.11 51.63 3.09 45.35 57.75 51.78 3.11	37	42.11 57.75 48.70 3.89 42.35 57.97 48.73 3.92

n = number of paired index values calculated; Min, minimum; Max, maximum; SD, standard deviation L, left side; R, right side; See Table

14

for the codes of the indices

Table 48 . Statistical evaluation of the asymmetry of indices of shape and robusticity calculated from paired bones in the Hungarian groups with (RD) and without riding deposit (NRD) and in the comparison group from Lisbon (LIS)

 48

	Index	n pairs	Z	RD p exact Asym. n pairs	Z	NRD p exact Asym. n pairs	Z	LIS p exact Asym.
	FEM I1	10 -0.153	.902	-	30 -0.227	.827	-	40 -1.068	.291	-
	FEM I2	13 -2.062	.040	R>L	40 -1.405	.163	-	40 -2.446	.014	R>L
	FEM I3	12 -1.490	.151	-	37 -1.124	.268	-	40 -0.746	.462	-
	FEM I4	7 -1.483	.188	-	24 -1.872	.061	-	38 -3.075	.002	L>R
	FEM I5	6 -0.524	.688	-	27 -0.408	.692	-	39 -1.429	.156	-
	PAT I1	5 -0.944	.438	-	16 -0.362	.744	-	26 -1.867	.062	-
	TIB I1	15 -2.103	.035	R>L	36 -3.243	.001	R>L	38 -2.248	.024	R>L
	TIB I2	15 -1.533	.135	-	42 -1.482	.140	-	39 -0.471	.646	-
	FIB I1	3	-	-	-	11 -2.045	.042	R>L	20 -1.736	.084	-
	TAL I1	12 -0.628	.569	-	27 -0.264	.804	-	36 -1.838	.066	-
	TAL I2	13 -0.314	.787	-	29 -1.139	.262	-	36 -0.470	.645	-
	TAL I3	12 -2.197	.027	L>R	28 -0.900	.377	-	36	0	1	-
	CAL I1	8 -1.014	.375	-	22 -0.503	.633	-	35 -0.453	.658	-
	CAL I2	9 -1.014	.375	-	29 -0.875	.392	-	37 -0.020	.988	-

Wilcoxon signed-rank test, two-tailed; p values in bold indicate a statistical significance at the .05 level; the asymmetry for FIB I1 was not tested in the RD group regarding the low sample size; Asym, asymmetry (side dominance); see Table

14

for the codes of the indices

Table 49 . Evaluation of the asymmetry (right minus left value) of the indices of shape and robusticity calculated from paired bones in the Hungarian groups with (RD) and without riding deposit (NRD) and in the comparison group from Lisbon (LIS), and statistical comparison between the three groups

 49

	Index	RD n Min Max Mean SD	n	NRD Min Max Mean SD	n	LIS Min Max Mean SD	H (df = 2)	p value Monte Carlo
	FEM I1 10 -0.88 0.55 -0.05 0.44 30 -0.94 0.97 0.04 0.43 40 -1.00 0.87 0.07 0.47 0.848	.663
	FEM I2 13 -4.55 12.06 3.50 5.31 40 -14.63 10.93 1.03 4.83 40 -13.60 14.06 2.24 6.30 3.174	.210
	FEM I3 12 -6.74 17.18 2.78 6.24 37 -7.71 9.09 0.46 3.60 40 -8.27 7.09 0.32 3.79 1.448	.491
	FEM I4	7 -2.02 0.63 -0.56 0.97 24 -1.63 1.83 -0.32 0.87 38 -3.77 2.74 -0.75 1.38 2.150	.358
	FEM I5	6 -0.69 0.60 -0.05 0.43 27 -0.82 1.16 0.05 0.50 39 -0.60 1.27 0.12 0.42 0.727	.709
	PAT I1	5 -3.69 3.51 -0.71 2.64 16 -4.58 3.92 -0.31 2.50 26 -6.87 2.90 -0.98 2.14 1.075	.596
	TIB I1	15 -0.52 1.06 0.29 0.46 36 -0.75 1.19 0.29 0.45 38 -0.38 0.86 0.15 0.34 3.849	.148
	TIB I2	15 -9.09 3.22 -1.54 3.48 42 -5.75 7.36 -0.59 3.12 39 -8.62 5.81 -0.44 3.52 1.186	.555
	FIB I1	3 0.26 0.60 0.48 0.19 11 -0.49 0.75 0.20 0.31 20 -1.13 1.70 0.22 0.60 1.928	.404
	TAL I1 12 -2.75 3.93 0.42 2.12 27 -3.48 5.78 0.03 2.00 36 -3.03 5.42 0.62 1.82 2.161	.338
	TAL I2 13 -1.68 1.88 0.02 1.03 29 -4.47 1.87 -0.38 1.47 36 -2.83 3.66 0.04 1.46 0.891	.643
	TAL I3 12 -6.81 2.73 -2.27 2.95 28 -6.09 7.01 -0.66 3.46 36 -5.91 8.48 0.12 3.53 3.617	.162
	CAL I1	8 -1.18 1.87 0.46 1.12 22 -2.06 3.57 0.19 1.49 35 -2.45 4.41 0.23 1.57 0.569	.764
	CAL I2	9 -1.95 2.32 0.39 1.28 29 -2.05 2.67 0.15 1.07 37 -2.61 4.41 0.03 1.32 0.920	.641

Kruskal-Wallis H test with Monte Carlo estimate for an exact test based on 10000 sampled tables; n, number of calculated index values; Min, minimum; Max, maximum; SD, standard deviation

  developed in research unit PACEA (UMR 5199, CNRS/University of Bordeaux, Pessac, France), including image processing with TIVMI® (Treatment and Increased Vision for Medical Imaging) software. It is based on the HMH (Half

Table 50 . Summary of the cortical bone canal organization differences observed between the three groups of entheses Medial-posterior diaphysis Antero-medial entheseal margin "Normal" entheses

 50

		Longitudinal; thin	Reticulated; rough
	"Mechanical" entheses	Longitudinal; thin	Preferentially oriented
	"Metabolic" entheses	Longitudinal; large	Loss of reticulation; irregular; wide; dense

Could µ-CT and 3D reconstructions help to identify activity-related entheseal changes?

  Certaines modifications pathologiques ou non-pathologiques observées sur les os humains peuvent être liées à des activités pratiquées au cours de la vie. Ceci résulte de la capacité des os à adapter leur forme et leur structure en réponse à des charges mécaniques. Les chercheurs ont considéré la reconstruction des activités des populations passées à partir des modifications squelettiques comme le « Saint Graal de la bioarchéologie », représentant en effet une sorte de but ultime difficilement accessible en raison de nombreux écueils méthodologiques qui doivent être pris en compte. Parmi toutes les activités, la pratique cavalière, en particulier, intéresse les bioarchéologues et les paléopathologistes depuis plusieurs décennies car elle a apporté des changements profonds et durables dans l'histoire de l'évolution culturelle humaine concernant des aspects majeurs tels que les échanges, les peuplements, la guerre, la subsistance, l'organisation sociale et les idéologies politiques. À cet égard, de nombreux types de modifications squelettiques ont été décrits comme faisant partie d'un "syndrome du cavalier", e et 10 e siècles, conduisant ainsi à la fondation du Royaume de Hongrie un siècle plus tard. Les cimetières de cette période fournissent souvent des cas de dépôts de matériel d'archerie et d'équitation ainsi que des ossements de chevaux associés aux individus dans les tombes. L'association étroite entre ces objets et les restes osseux, ainsi que le contexte historique bien connu, permettent de postuler que les individus concernés ont pratiqué l'équitation au cours de leur vie. Ces populations figurent donc parmi les plus pertinentes pour mener des études méthodologiques sur les modifications squelettiques liées aux activités et, en particulier, à la pratique cavalière. Cette recherche doctorale a deux objectifs principaux. Le premier est de contribuer à la recherche sur la reconstitution des activités des populations passées en identifiant des modifications squelettiques qui pourraient être associées plus fiablement à la pratique cavalière, en particulier. Le deuxième objectif est d'apporter une contribution ethnoarchéologique en améliorant éventuellement notre compréhension des pratiques funéraires des sociétés de la période de la Conquête hongroise. Nous avons limité l'influence du sexe et de l'âge sur le développement des modifications squelettiques en n'incluant que des individus adultes masculins au sein de notre matériel d'étude. Nous avons ainsi sélectionné un échantillon de 67 individus issus du cimetière hongrois de Sárrétutudvari-Hízóföld, datant du 10 e siècle, qui a été divisé en deux groupes d'individus, selon la présence ou l'absence de dépôt lié à la pratique cavalière dans leur tombe (17 et 50 individus, respectivement). Nous avons également sélectionné un groupe de comparaison moderne (19-20 e siècle) de 47 individus présumés non-cavaliers, au sein de la collection documentée de Lisbonne. De plus, les individus adultes jeunes et matures ont été distingués des adultes plus âgés pour certaines analyses de façon à limiter l'influence du vieillissement. En sus de ces modifications squelettiques, nous proposons également de considérer la fréquence plus élevée de fractures du membre supérieur -notamment de la clavicule -, par rapport aux fractures d'autres os ou régions, comme un indicateur complémentaire. Par ailleurs, les comparaisons entre groupes pour ces modifications squelettiques ont révélé que les individus du cimetière hongrois qui n'avaient pas de dépôt lié à la pratique cavalière dans leur tombe montaient aussi probablement à cheval malgré tout. Cela expliquerait pourquoi les sources historiques mentionnent des cavaliers en très grand nombre parmi les populations de l'époque de la Conquête alors qu'une minorité seulement des tombes du bassin des Carpates contiennent des dépôts liés à la pratique cavalière. Cette pratique funéraire pourrait, par conséquent, plutôt revêtir une signification sociale ou symbolique.

	Les analyses statistiques ont principalement révélé des différences significatives entre les
	groupes hongrois avec ou sans dépôt lié à la pratique cavalière et le groupe de comparaison de
	Lisbonne. Ces différences concernaient surtout diverses modifications squelettiques qui
	peuvent s'expliquer par la pratique de l'équitation, telles que certaines modifications des
	enthèses au niveau de l'os coxal, du fémur, du tibia et du calcanéum, une adaptation
	morphologique sur le col fémoral, la présence de hernies discales à la jonction thoraco-
	lombaire, ou l'ovalisation de l'acétabulum sur l'os coxal. Nos résultats suggèrent que ces
	modifications squelettiques peuvent être utilisées avec confiance pour évaluer, statistiquement,
	la possibilité qu'une population d'intérêt pratiquait l'équitation. Pour ce faire, il convient de

c'est-à-dire comme étant liés à la pratique régulière ou intense de l'équitation. Cependant, différents facteurs de biais caractérisent ce champ de recherche, dont le manque de spécificité des modifications et leur étiologie multifactorielle. Cette situation, conjuguée à l'absence, dans la plupart des études, de preuves contextuelles reliant les individus à une activité, ainsi qu'à l'absence de groupes de comparaison, donne souvent lieu à des interprétations limitées ou peu fiables des modifications squelettiques en termes d'activités spécifiques, comme la pratique cavalière. Les sources archéologiques et historiques attestent que des tribus de populations seminomades ont conquis le bassin des Carpates à l'aide de puissantes armées d'archers montés au tournant des 9 Nous avons analysé différents types de modifications squelettiques couramment utilisées comme indicateurs d'activité et de comportement dans les populations passées : les modifications des enthèses (aux sites d'insertion des muscles), modifications articulaires, variations anatomiques, modifications vertébrales et les lésions traumatiques. Diverses mesures directes des os des membres inférieurs ont également été utilisées pour calculer des indices de forme et de robustesse. Nous avons sélectionné ces modifications squelettiques en considérant les aspects anatomique et fonctionnel, et en tenant compte des précédentes recherches en bioanthropologie et des données de la médecine sportive sur l'équitation. comparer les fréquences et les valeurs de ces traits avec des populations pertinentes de cavaliers et de non-cavaliers connus. À cet égard, les données que nous avons enregistrées pourraient être utilisées dans le cadre de futures analyses comparatives.

Table 14 .

 14 Indices of shape and robusticity calculated from direct measurements on the lower limb bones and used for intergroup comparisons ..................................................................... 89

Table 15 .

 15 Frequency of all entheseal changes observed in the young and mature adult individuals (YMA) from the Hungarian groups with (RD) and without riding deposit (NRD) and the comparison group from Lisbon (LIS), and statistical comparison .............................. 98

Table 16 .

 16 Frequency of young and mature adult individuals (YMA) with at least one enthesis affected by changes in the Hungarian groups with (RD) and without riding deposit (NRD) and the comparison group from Lisbon (LIS), and statistical comparison ..................................... 98

Table 17 .

 17 Frequency of entheseal changes observed in young and mature adult individuals (YMA) from the Hungarian groups with (RD) and without riding deposit (NRD) and the comparison group from Lisbon (LIS), and statistical comparison ......................................... 100

Table 18 .

 18 Frequency of all entheseal changes observed in individuals in all adult age categories from the Hungarian groups with (RD) and without riding deposit (NRD) and the comparison group from Lisbon (LIS), and statistical comparison ............................................................ 101

Table 19 .

 19 Frequency of individuals in all adult age categories with at least one enthesis affected by changes in the Hungarian groups with (RD) and without riding deposit (NRD) and the comparison group from Lisbon (LIS), and statistical comparison ......................................... 101

Table 20 .

 20 Frequency of entheseal changes observed in individuals in all adult age categories from the Hungarian groups with (RD) and without riding deposit (NRD) and the comparison group from Lisbon (LIS), and statistical comparison ............................................................ 103

Table 21 .

 21 Bilateral asymmetry for the entheseal changes observed on paired bones in individuals in all adult age categories from the Hungarian groups with (RD) and without riding deposit (NRD) and the comparison group from Lisbon (LIS), and statistical comparison ... 105

Table 22 .

 22 Frequency of all joint changes observed in the young and mature adult individuals (YMA) from the Hungarian groups with (RD) and without riding deposit (NRD) and the comparison group from Lisbon (LIS), and statistical comparison ......................................... 106

Table 23 .

 23 Frequency of young and mature adult individuals (YMA) with at least one joint affected by changes in the Hungarian groups with (RD) and without riding deposit (NRD) and the comparison group from Lisbon (LIS), and statistical comparison ................................... 106

Table 24 .

 24 Frequency of joint changes observed in young and mature adult individuals (YMA) from the Hungarian groups with (RD) and without riding deposit (NRD) and the comparison group from Lisbon (LIS), and statistical comparison ............................................................ 107

Table 25 .

 25 Frequency of perifoveal osteophytes (femoral head) observed in young and mature adult individuals (YMA) from the Hungarian groups with (RD) and without riding deposit (NRD) and the comparison group from Lisbon (LIS), and statistical comparison ................ 108

Table 26 .

 26 Frequency of joint changes observed in individuals in all adult age categories from the Hungarian groups with (RD) and without riding deposit (NRD) and the comparison group from Lisbon (LIS), and statistical comparison ....................................................................... 108

Table 27 .

 27 Frequency of individuals in all adult age categories with at least one joint affected by changes in the Hungarian groups with (RD) and without riding deposit (NRD) and the comparison group from Lisbon (LIS), and statistical comparison ......................................... 109

Table 28 .

 28 Frequency of joint changes observed in individuals in all adult age categories from the Hungarian groups with (RD) and without riding deposit (NRD) and the comparison group from Lisbon (LIS), and statistical comparison ....................................................................... 109

Table 29 .

 29 Frequency of perifoveal osteophytes (femoral head) observed in individuals in all adult age categories from the Hungarian groups with (RD) and without riding deposit (NRD) and the comparison group from Lisbon (LIS), and statistical comparison ............................ 110

Table 30 .

 30 Bilateral asymmetry for the joint changes observed in individuals in all adult age categories from the Hungarian groups with (RD) and without riding deposit (NRD) and the comparison group from Lisbon (LIS), and statistical comparison ......................................... 111

Table 31 .

 31 Bilateral asymmetry for the perifoveal osteophytes (femoral head) observed in individuals in all adult age categories from the Hungarian groups with (RD) and without riding deposit (NRD) and the comparison group from Lisbon (LIS), and statistical comparison ... 111

Table 32 .

 32 Frequency of all morphological variants of the femur in the Hungarian groups with (RD) and without riding deposit (NRD) and the comparison group from Lisbon (LIS), and statistical comparison ............................................................................................................. 112

Table 33 .

 33 Frequency of individuals with at least one morphological variant on the femur in the Hungarian groups with (RD) and without riding deposit (NRD) and the comparison group from Lisbon (LIS), and statistical comparison ....................................................................... 112

Table 34 .

 34 Frequency of morphological variants of the femur in the Hungarian groups with (RD) and without riding deposit (NRD) and the comparison group from Lisbon (LIS), and statistical comparison ............................................................................................................................. 113

Table 35 .

 35 Bilateral asymmetry for the morphological variants of the femur in the Hungarian groups with (RD) and without riding deposit (NRD) and the comparison group from Lisbon (LIS), and statistical comparison ............................................................................................ 115

Table 36 .

 36 Frequency of individuals with at least one vertebra affected by a Schmorl's node in

Table 50 .

 50 Summary of the cortical bone canal organization differences observed between the three groups of entheses ......................................................................................................... 174

Wilcoxon signed-rank test, two-tailed; L, left side; R, right side

L, left; RD, riding deposit; NRD, no riding deposit; the probability of being a male is calculated with a minimum of 4 measurements; values in bold indicate that the sex can be assessed at the threshold of 0.95

R, right; RD, riding deposit; NRD, no riding deposit; the probability of being a male is calculated with a minimum of 4 measurements; values in bold indicate that the sex can be assessed at the threshold of 0.95

Sex DSP Sex MorphoSex DNA Sex Final study

M, male; I, indeterminate; NO, not observable; NP, not performed (the morphological visual method was not systematically performed when the DSP already allowed a successful sex diagnosis)

CHAPTER 4. DISCUSSION

The position that is privileged by riders is characterized by a pelvis in retroversion (tilted backward) and a diminished lumbar lordosis that allows a better absorption of vertical stresses [START_REF] Auvinet | Lombalgies et équitation[END_REF][START_REF] Humbert | L'équitation et ses conséquences sur le rachis lombaire du cavalier : à propos de 123 observations[END_REF]. When the hip is placed in that position, pressure is applied by the femoral heads on the superior and anterosuperior parts of the acetabula [START_REF] Baillif-Ducros | La pratique de la monte à cheval au haut Moyen Âge (fin Ve-VIIe siècle) dans le nord-est de la Gaule. État des connaissances archéologiques[END_REF][START_REF] Baillif-Ducros | Approche méthodologique pour distinguer un ensemble lésionnel fiable de la pratique cavalière. Exemple du squelette de la tombe 11 du site de « La Tuilerie » à Saint-Dizier (Haute-Marne), VIe siècle[END_REF]Figure 38). Although the possibility that this skeletal modification could also result from other postures cannot be excluded, the vertical ovalization of the acetabulum can clearly be explained by the practice of horse riding.

Methodological research on the shape of the acetabulum as a possible indicator of the practice of horse riding was initiated by [START_REF] Erickson | Fourier analysis of acetabular shape in Native American Arikara populations before and after acquisition of horses[END_REF], who performed a Fourier analysis of the shape of the acetabulum on adult males from two Native American Arikara populations, respectively presumed riders and non-riders. They observed significant differences (set level of α = .1) between both groups, with expanded anterosuperior acetabular rims in the presumed rider group. Inspired by this study, [START_REF] Garofalo | The osteologic markers of horseback riding: An examination of two medieval English populations[END_REF], with linear measurements taken at intervals of ten degrees from the midpoint of the acetabular notch to the acetabular rim, obtained significant differences between two British medieval series and individuals from the Robert J. Terry Anatomical Skeletal Collection. These differences were, however, not correlated with other presumed horse riding-related skeletal changes, and the author could not positively associate the elongation of the anterosuperior margin of the acetabulum with the practice of horse riding within those groups, mentioning individual skeletal variation as a possible causal factor. Later on, a morphometric analysis of the acetabular rim shape performed with the use of 3D scans on samples of ancient Mongolian pastoralists revealed significant differences between the Scythians and other Mongolian samples, but not with a reference collection [START_REF] Eng | Morphometric analysis of acetabular rim shape among ancient Mongolian pastoralists[END_REF]. According to the authors, these results could be related to the riding style or sample and methodological limitations. More recently, [START_REF] Ciurletti | Analisi biomeccanica del femore e del coxale per comprendere l'economia di sussistenza e il comportamento occupazionale legato all'uso del cavallo nella populazione della necropoli di Olmo di Nogara (Bronzo medio, Verona)[END_REF] studied individuals from the Bronze Age necropolis of Olmo di Nogara, in Veneto, Italy, and analyzed the shape of the acetabulum (Feret's analysis, shape descriptors) with variables obtained using photographs. However, the limited sample size, and especially, the lack of comparison groups with the confirmed presence of horse riders and nonriders, limited the interpretations. Despite this, high frequencies of the extension of the superior rim of the acetabulum, visually scored, were noted, especially in males (95%) compared to females (58%). This, and the presence of other morphological variants and entheseal changes on the femur and the coxal bone led the author to confirm the hypothesis of the practice of horse riding in the population.

SUMMARY

Some pathological or nonpathological changes observed on human bones can be related to activities practiced during life. This results from bones' ability to adapt their shape and structure in response to mechanical loading. Scholars have considered the reconstruction of activities from skeletal changes in past populations as "Bioarchaeology's Holy Grail", representing, in fact, a sort of ultimate goal which is hardly accessible due to many methodological pitfalls that must be acknowledged. Among all activities, horse riding, in particular, has interested bioarchaeologists and paleopathologists for several decades as it brought profound and lasting changes in the history of human cultural evolution concerning major aspects such as trade, settlement, warfare, subsistence, social organization, and political ideology. In that regard, many types of skeletal changes have been described as part of a "horse riding syndrome", i.e., as being related to the regular or intense practice of horse riding. The lack of specificity of changes and their multifactorial etiology are, however, among the various confounding factors that characterize this field of research. This, together with the absence, in most of studies, of contextual evidence connecting the individuals with an activity and the lack of comparison groups, often result in limited or unreliable interpretations of skeletal changes in terms of specific activities, such as riding.

Archaeological and historical sources attest that tribes of semi-nomadic populations conquered the Carpathian Basin with powerful armies of mounted archers at the turn of the 9th and 10th centuries, which led to the foundation of the Kingdom of Hungary a hundred years later. Cemeteries from that period often provide cases of deposits of archery and horse riding equipment as well as horse bones associated with the individuals in the graves. The close association between these items and the skeletons, together with the well-known historical context, allows postulating that the concerned individuals practiced horse riding during their life. Those populations are, thus, among the most pertinent to be used to perform methodological investigations on activity-related skeletal changes, and, on horse riding, in particular.

This doctoral research has two main objectives. The first one is to contribute to the research on activity reconstructions in past populations with the identification of skeletal changes that could more reliably be associated with the practice of horse riding, in particular. The second objective is to bring an ethnoarchaeological contribution by possibly improving our understanding of the funerary practices of the societies from the Hungarian Conquest period.

We limited the effect of sex and age on the development of skeletal changes by including only adult males in our materials. This way, we selected a sample of 67 individuals from the 10th-century Hungarian cemetery of Sárrétudvari-Hízóföld, which was divided into two groups of individuals, according to the presence or absence of riding deposit in their grave (17 and 50 individuals, respectively). We also selected a modern (19-20th century) comparison group of 47 presumed non-rider individuals from the documented collection of Lisbon. Moreover, the young and mature adult individuals were distinguished for certain analyses to limit the influence of aging.

We analyzed different types of skeletal changes commonly used as indicators of activity and behavior in past populations: entheseal changes (at the muscles attachment sites), joint changes, morphological variants, vertebral changes, and traumatic lesions. Various direct measurements of the lower limb bones were also used to calculate indices of shape and robusticity. We selected these skeletal changes considering anatomical and functional aspects, and taking into account the bioanthropological and sports medicine literature on horse riding.

Statistical analyses mostly revealed significant differences between the Hungarian groups with or without riding deposit and the comparison group from Lisbon. These differences concerned especially various skeletal changes that can be explained by the practice of horse riding, such as some entheseal changes at the coxal bone, femur, tibia, and calcaneus, a morphological adaptation on the femoral neck, intervertebral disc herniations at the thoracolumbar junction, or the ovalization of the acetabulum on the coxal bone. Our results suggest that these skeletal changes can be used with confidence to evaluate, statistically, the possibility that a population of interest was practicing horse riding. For this purpose, one should compare the frequencies and values of these features with pertinent populations of known riders and non-riders. In this respect, future comparative analyses could use the data that we have recorded. Along with these skeletal changes, we also propose to consider the higher frequency of fractures of the upper limb -notably the clavicle -, relatively to other bones' fractures, as a complementary indicator.

On another note, comparisons between groups for these skeletal changes revealed that the individuals from the Hungarian cemetery without riding-related deposits in their grave were likely riding horses as well. This would explain why historical sources mention great numbers of riders in the populations from the Conquest period while only a minority of the graves in the Carpathian basin contain riding deposits. This funerary practice could, as a consequence, carry a more social or symbolic significance.

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ABSTRACT

Some changes observed on human bones can help to reconstruct past populations' activities, such as horse riding. To identify reliable skeletal indicators for this practice, we relied on populations from the Hungarian Conquest period (10th century), who were known for their powerful mounted archers. In many cemeteries from that period, horse riding equipment and horse bones associated with the individuals in the graves confirm the presence of riders. We analyzed morphological and pathological differences between the individuals with and without riding deposit, and with modern presumed non-riders, and we identified several types of skeletal changes on the hip bone, femur, vertebrae, or the foot that could be related to horse riding. We also observed that the use of modern methods like microtomography and 3D reconstructions could help with the identification of some activities. Our research sheds new light on the reconstruction of the lifestyles of past populations.

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