ADT Androgen deprivation therapy BMAD

ACKNOWLEDGEMENT

This thesis would not have been accomplished without the encouragement and support of many incredible people. My appreciations and thankfulness to all of them for being part of this journey and making this thesis possible. Without their enthusiasm, encouragement, support and continuous optimism this thesis would hardly have been completed.

First of all, I would especially like to thank my thesis director at the University of Balamand, Pr. Rawad El Hage, for the trust he placed in me throughout my work, for all his expertise, patience and professionalism, teaching me rigorous work and scientific thinking. It has been a pleasure and a great honour to work under your leadership.

Furthermore, I want to thank Dr Hervé Devanne for helping me conducting this PhD thesis.

Moreover, I would like also to thank Dr Gauter Zunquin for his support in the various stages of the development of this project, and for guiding me effectively.

I also want to thank all the individuals who have agreed to participate in these different research protocols especially the recreational football players. You became my best friends.

Thanks to all the members of the jury and the reporters for agreeing to participate in the evaluation of this thesis.

Finally, my sincere and deep appreciation to my family for their persistent and limitless love and help. I am thankful to my sisters, Nathalie and Marie Therese for continually being there for me. I am always grateful to my parents, my Father GL Dr Pascal Finianos and my mother Salma for giving me the opportunities and chances that have made me who I am. They always unselfishly motivated me to discover new directions in life and seek my own destiny. This journey would not have been accomplished without them, and I devote this achievement to them. I likewise need to thank every one of my friends and particularly Mariette Mouawad for her persistent help and support. [START_REF] Seeman | Pathogenesis of bone fragility in women and men[END_REF]. ..... Figure 4: Distribution of osteoporosis cases in major European countries (2010) [START_REF] Hernlund | Osteoporosis in the European Union: medical management, epidemiology and economic burden[END_REF]

LIST OF FIGURES

Figure 9:

The effect of an increase in cortex diameter on bone compression and bending strength with no change in areal density [START_REF] Bouxsein | Determinants of skeletal fragility[END_REF] [START_REF] René | Maximizing bone mineral mass gain during growth for the prevention of fractures in the adolescents and the elderly[END_REF]. Figure 12: Bone mineral content gain in relation to age and sex [START_REF] Bailey | A Six-Year Longitudinal Study of the Relationship of Physical Activity to Bone Mineral Accrual in Growing Children: The University of Saskatchewan Bone Mineral Accrual Study[END_REF]........... [START_REF] Beck | Predicting femoral neck strength from bone mineral data. A structural approach[END_REF] and their clinical importance. .......... Table 4: [START_REF] Karlamangla | Hip fracture risk assessment using composite indices of femoral neck strength: the Rancho Bernardo study[END_REF] bone resistance indices and their clin ical importance. .......... Table 5: The major modifiable and non-modifiable risk factors of osteoporosis. .................. Table 6: 19: Clinical characteristics and bone variables of the study population at baseline. .. Table 20: Physical performance variables of the study population before the intervention. Table 21: Clinical characteristics and bone variables of the Former football group and the inactive controls (C,RF30 and RF60 combined) 37: Differences in the percentages of variation related to clinical and bone parameters among control, recreational football 30 and recreational football 60 groups. ....................... Table 38: Differences in the percentages of variation related to physical performance parameters among control, recreational football 30 and recreational football 60 groups. .... Table 39: 45: Differences in players' attendance to game between both recreational groups. ... Table 46: Correlations between the percentage of variation of the clinical and bone performance variables and percentage of attendance of the study population. ..................... Table 47: Correlations between the percentage of variation of the physical performance variables and percentage of attendance of the recreational groups........................................ Table 48: Correlations between the percentage of variation of the physical performance variables and the percentage of variation of bone variables in RF60 and RF30. ..................

LIST OF TABLES

INTRODUCTION

Osteoporosis is "the most common bone disease in humans and it is characterized by low bone mineral density (BMD) and deterioration of bone microarchitecture leading to increased risk of fracture" (WHO, 1994). It is a major public health problem which not only affects women as it is traditionally believed but affects men as well. Hip and vertebral fractures are the most common fractures associated with osteoporosis [START_REF] Warriner | Which Fractures Are Most Attributable to Osteoporosis[END_REF]. Hip fractures are considered to be the most serious of these fractures because they are correlated to a high rate of morbidity and mortality [START_REF] Zaheer | Osteoporosis: Prevention and Treatment[END_REF]. An increased risk of death during the first year after hip fracture is found in both sexes but at a higher rate in men compared to women [START_REF] Chrischilles | A model of lifetime osteoporosis impact[END_REF][START_REF] Magaziner | Excess mortality attributable to hip fracture in white women aged 70 years and older[END_REF][START_REF] Melton | Fractures attributable to osteoporosis: report from the National Osteoporosis Foundation[END_REF]. Currently, the diagnosis of osteoporosis is based on measuring BMD by Dual-energy X-ray absorptiometry (DXA) (a T-score ≤ -2.5 means the existence of osteoporosis).

In 2001, a group of experts defined osteoporosis as "a skeletal disorder characterized by low bone strength which increases the risk of fractures" (NIH, 2001). According to these experts, bone strength is influenced by three major factors which are the total bone mass, the geometric distribution of the mass, and the material properties (NIH, 2001). BMD measurements by DXA reflect some of the components of bone strength, including bone mass. BMD, which is influenced by several factors such as genetic factors, ethnicity, gender, nutrition and mechanical factors (such as body weight and physical activity), is one of the best determinants of fracture risk [START_REF] Jean-Philippe | The importance and relevance of peak bone mass in the prevalence of osteoporosis[END_REF]Compston, 2002;[START_REF] El Hage Rawad | Daily calcium intake and body mass index in a group of Lebanese adolescents[END_REF][START_REF] Eisman | Genetics of osteoporosis[END_REF][START_REF] Pouresmaeili | A comprehensive overview on osteoporosis and its risk factors[END_REF]. BMD values of Lebanese people are generally lower than US and European values [START_REF] Maalouf | Bone mineral density of the Lebanese reference population[END_REF][START_REF] El Hage Rawad | Bone mass in a group of Lebanese girls from Beirut and French girls from Orleans[END_REF]. This may be due to the deficiency in vitamin D levels and low calcium consumption that is commonly found in this population [START_REF] El Hage Rawad | Daily calcium intake and body mass index in a group of Lebanese adolescents[END_REF][START_REF] Chakhtoura | Vitamin D in the Middle East and North Africa[END_REF][START_REF] Salamoun | Low calcium and vitamin D intake in healthy children and adolescents and their correlates[END_REF][START_REF] Alwan | Vitamin D and Trabecular Bone Score in a Group of Young Lebanese Adults[END_REF]. Moreover, the majority of Lebanese children and youth are inactive and do not follow the physical activity guideline recommendations [START_REF] Nader | First Physical Activity Report Card for Children and Youth in Lebanon[END_REF][START_REF] Fazah | Activity, inactivity and quality of life among Lebanese adolescents[END_REF].

However, in clinical practice, it is very common to notice fractures in subjects with normal BMD or low BMD values but above the threshold for densitometric osteoporosis [START_REF] Roux | The predictive value of trabecular bone score (TBS) on whole lumbar vertebrae mechanics: an ex vivo study[END_REF][START_REF] Briot | Added value of trabecular bone score to bone mineral density for prediction of osteoporotic fractures in postmenopausal women: the OPUS study[END_REF][START_REF] Kanis | Assessment of fracture risk and its application to screening for postmenopausal osteoporosis: synopsis of a WHO report. WHO Study Group[END_REF]. Poor bone geometry and deteriorated bone quality are the reason of these fractures [START_REF] Bouxsein | Determinants of skeletal fragility[END_REF]. Subjects with same BMD can present different levels of bending and compression mechanical resistance depending on their bone dimensions and geometry [START_REF] Bouxsein | Determinants of skeletal fragility[END_REF]. In addition, subjects with normal BMD but deteriorated microarchitecture (bad material properties) may be prone to fractures (Dalle [START_REF] Carbonare | Bone microarchitecture as an important determinant of bone strength[END_REF]. In addition to BMD, other densitometric variables also predict osteoporotic fracture such as Beck's geometric indices and femoral neck bone resistance indices established by Karlamangla (Bousson et al., 2015;[START_REF] Beck | Predicting femoral neck strength from bone mineral data. A structural approach[END_REF][START_REF] Karlamangla | Hip fracture risk assessment using composite indices of femoral neck strength: the Rancho Bernardo study[END_REF][START_REF] Ayoub | DXA-based variables and osteoporotic fractures in Lebanese postmenopausal women[END_REF]. In order to reduce the risk of fractures, it is important to increase peak bone mass (normally established around the age of 25) and to reduce the risk factors for osteoporosis (smoking, sedentary lifestyle, absence of physical activity, alcoholism, weight loss, intake of certain drugs) throughout life [START_REF] Jean-Philippe | The importance and relevance of peak bone mass in the prevalence of osteoporosis[END_REF][START_REF] Hage | Geometric indices of hip bone strength in young female football players[END_REF]. Increasing physical activity levels through any period over lifespan could help to decrease the risk of bone loss and osteoporotic fractures [START_REF] Carter | Physical Activity and Bone Health[END_REF]. There are types of physical activity that are superior to others in affecting bone health.

It has been shown that individuals who participated in high impact sport (for example: volleyball and gymnastics) had significantly higher BMD compared to those who participated in low-impact sports (such as cycling and swimming). Furthermore, there is compelling data that shows that a consistent physical activity practice, especially weight bearing and impact activities, helps to prevent bone loss that is associated with aging. Previous reports have shown that exercise before puberty may confer residual benefits in BMD in adulthood [START_REF] Eser | Skeletal benefits after long-term retirement in former elite female gymnasts[END_REF][START_REF] Bass | Exercise before puberty may confer residual benefits in bone density in adulthood: studies in active prepubertal and retired female gymnasts[END_REF].

Soccer is considered a high impact weight-bearing sport [START_REF] Kohrt | Physical Activity and Bone Health[END_REF]. Practicing soccer during adolescence and young adulthood has a positive osteogenic effect on bone health parameters. However, longitudinal studies that aim to investigate the effects of football practice on bone health parameters in middle-aged men are rare. Moreover, the best frequency of training to stimulate osteogenic adaptation needs to be defined in this age group.

The first objective of this PhD thesis was to explore the relationships between several physical performance variables and bone parameters in a group of middle-aged men.

The second objective was to compare composite indices of femoral neck strength ((compression strength index (CSI), bending strength index (BSI) and impact strength index (ISI)) in inactive middle-aged men and aged matched former football players.

Finally, the third objective was to compare the effects of two recreational football protocols (RF30: 2x30min vs RF60: 2x60min for 1 year) on bone health and physical performance parameters in a group of healthy middle-aged men. This thesis is based on three hypotheses. First maximal oxygen consumption and lower body maximal strength are positively correlated to BMD in middle-aged men.

Second, long term former football practice is associated with higher composite indices of femoral neck strength in healthy middle-aged men.

Third, both recreational football protocols (2x30min and 2x60min per week) improve bone health and physical performance variables in healthy middle-aged men.

FIRST PART: LITERATURE REVIEW 1. Osteoporosis

Definition of osteoporosis

According to the world health organization in 1994, "Osteoporosis is a worldwide disease characterized by reduction of bone mass and alteration of bone architecture resulting in increased bone fragility and increased fracture risk" (Kanis,1994). The definition of osteoporosis is thus based on the quantity reduction of bone mass and the quality deterioration of bone tissue. Osteoporosis increases the risk of bone fracture that mainly occurs with minor shock like falling from a vertical position [START_REF] Akkawi | Osteoporosis: Current Concepts[END_REF].

In 2001, this definition was simplified to become as "a skeletal disorder characterized by compromised bone strength leading to an increased risk of fracture" (NIH, 2001).

In most cases, patients do not know if they are vulnerable to bone fractures since their deterioration happens quietly, gradually and without any signs or symptoms until the fracture occurs [START_REF] Van Oostwaard | Osteoporosis and the Nature of Fragility Fracture: An Overview[END_REF]. Therefore, it is very essential to have an early diagnosis for osteoporosis. This can be done by performing a dual energy X-ray absorptiometry (DXA) examination [START_REF] Kuo | Bone biomarker for the clinical assessment of osteoporosis: recent developments and future perspectives[END_REF]. [START_REF] Kanis | Assessment of fracture risk and its application to screening for postmenopausal osteoporosis: synopsis of a WHO report. WHO Study Group[END_REF]. By knowing the value of the T-score of each site, osteoporosis could be diagnosed when the T-value is lower than -2.5 SD of the mean value of a population that is young and healthy [START_REF] Cosman | Clinician's Guide to Prevention and Treatment of Osteoporosis[END_REF]. Moreover, the WHO (1994) categorised the diagnostics of osteoporosis as follows:

Normal

T-score > -1

Osteopenia T-score is between -1 and -2.5

Osteoporosis T-score is strictly less than -2.5

Severe osteoporosis T-score <-2.5 with the presence of one or more fractures

According to International Society for Clinical Densitometry (ISCD), the diagnostic standards of the WHO mentioned above should be applied only to postmenopausal women and to men over the age of 50 [START_REF] Shuhart | Executive Summary of the 2019 ISCD Position Development Conference on Monitoring Treatment, DXA Cross-calibration and Least Significant Change, Spinal Cord Injury, Peri-prosthetic and Orthopedic Bone Health, Transgender Medicine, and Pediatrics[END_REF]. On the other hand, children and adults that are under the age of 50 must use the Z-scores rather than the T-scores. A Z-score of -2.0 or lower is defined as "below the expected range for age," and a Z-score above -2.0 is "within the expected range for age" [START_REF] Shuhart | Executive Summary of the 2019 ISCD Position Development Conference on Monitoring Treatment, DXA Cross-calibration and Least Significant Change, Spinal Cord Injury, Peri-prosthetic and Orthopedic Bone Health, Transgender Medicine, and Pediatrics[END_REF].

The T-score is defined as "the difference between a patient's BMD and that of a young normal population divided by the standard deviation of the young normal population" as follows [START_REF] Cummings | Clinical use of bone densitometry: scientific review[END_REF]:

T˗score = 𝑃𝑎𝑡𝑖𝑒𝑛𝑡 𝐵𝑀𝐷 -𝑌𝑜𝑢𝑛𝑔 𝑛𝑜𝑟𝑚𝑎𝑙 𝑚𝑒𝑎𝑛 𝐵𝑀𝐷 𝑆𝑡𝑎𝑛𝑑𝑎𝑟𝑑 𝑑𝑒𝑣𝑖𝑎𝑡𝑖𝑜𝑛 𝑜𝑓 𝑦𝑜𝑢𝑛𝑔 𝑛𝑜𝑟𝑚𝑎𝑙 𝑝𝑜𝑝𝑢𝑙𝑎𝑡𝑖𝑜𝑛
In addition to the T-score, the Z-score is calculated similarly to the T-score but instead of using a young BMD as a reference, similar age, race, and sex of the patient must be used [START_REF] Zhou | Normative Bone Mineral Density Z-Scores for Canadians Aged 16 to 24 Years: The Canadian Multicenter Osteoporosis Study[END_REF].

Reference data

On most densitometers to this day, reference data for males were young males, and for females were young females; for example, T-scores in men are the result of the comparison with a normal young male population [START_REF] Binkley | Osteoporosis Diagnosis in Men: The Tscore Controversy Revisited[END_REF]. Since the average BMD of the normal young population is greater in males than in females, using the male reference database will produce a lower T-score compared to when female database is used. However, we know that the risk of bone fracture in men is similar to women at the same BMD, so using sex-specific database (for males) is inappropriate and affects the diagnosis of osteoporosis [START_REF] Binkley | What are the criteria by which a densitometric diagnosis of osteoporosis can be made in males and non-Caucasians?[END_REF]. As a result, normal young female data was used for both sexes for the femoral neck T-score as recommended by the IOF [START_REF] Kanis | Towards a diagnostic and therapeutic consensus in male osteoporosis[END_REF]. The ISCD was previously endorsing this position. White females, aged between 20 and 29 years were the standard reference database (NHANES III database) to calculate the T-score in many studies [START_REF] Watts | 2013 International Society for Clinical Densitometry Position Development Conference: Task Force on Normative Databases[END_REF].

Dual energy X-ray absorptiometry (DXA)

DXA scanners have been available since 1987. According to the WHO, DXA is considered as the gold standard to assess bone density [START_REF] Garg | Dual energy X-ray absorptiometry: Pitfalls in measurement and interpretation of bone mineral density[END_REF]. It is the most commonly used method to determine BMD and therefore to diagnose osteoporosis. Before introducing DXA, many devices were mainly used for osteoporosis diagnostics (for example: Dual and single photon Absorptiometry) [START_REF] Pisani | Screening and early diagnosis of osteoporosis through X-ray and ultrasound based techniques[END_REF]. DXA has many advantages compared to its antecedents, including a decrease in radiation exposure, an energy source that is more stabilised, a faster pace and a more precise data acquisition. The investment in a DXA device is small compared to 3D imaging devices. In addition, DXA tests are mainly inexpensive.

DXA measurements are validated in adults, adolescents and children [START_REF] Weaver | The National Osteoporosis Foundation's position statement on peak bone mass development and lifestyle factors: a systematic review and implementation recommendations[END_REF].

A DXA machine involves an examination table for the patient, a mobile part below the patient that produces X-ray (X-ray source) and a system above the examination table that detects the produced radiation. The X-ray source and the X-ray detector move together and are located precisely in an opposite way (figure 2) Figure 2: Schematic representation of DXA scan's X-rays source and detector system [START_REF] Pisani | Screening and early diagnosis of osteoporosis through X-ray and ultrasound based techniques[END_REF].

Dual energy X-ray absorptiometry as its name shows, uses X-ray that is composed of dual photon energy (high and low; constant and pulsed energy) [START_REF] Pisani | Screening and early diagnosis of osteoporosis through X-ray and ultrasound based techniques[END_REF]. It is a technology that measures the attenuation of X-rays (of high-energy and low-energy) passing through tissues of varying densities. In addition to bone mineral content, DXA can calculate many bone variables (table 2). [START_REF] Ammann | Cooperation between the European Foundation for Osteoporosis and the National Osteoporosis Foundation of the USA[END_REF].

Variables tested by DXA

Bone mineral density BMD BMD is the best determinant of the mechanical strength of bone [START_REF] Ammann | Cooperation between the European Foundation for Osteoporosis and the National Osteoporosis Foundation of the USA[END_REF].

Bone mineral apparent density BMAD BMAD is an estimate of volumetric BMD [START_REF] Katzman | Clinical and anthropometric correlates of bone mineral acquisition in healthy adolescent girls[END_REF]. Its use in children and adolescents is recommended [START_REF] Carter | New approaches for interpreting projected bone densitometry data[END_REF].

The ratio of bone mineral density to height BMD/HEIGHT It is used as an index of the volumetric BMD expressed in g/cm 3 (Reid et al., 1992).

The ratio of bone mineral density to body mass index BMD/BMI It is used to evaluate the increase in BMD relative to mass [START_REF] Laet | Body mass index as a predictor of fracture risk: a meta-analysis[END_REF].

The ratio of bone mineral content to height BMC/HEIGHT It is used in children and adolescents to get an idea about the level of bone mineralization for a given height [START_REF] Leonard | Obesity during childhood and adolescence augments bone mass and bone dimensions[END_REF].

The ratio of bone mineral content to lean mass BMC/LM This ratio is used to find out if bone mineralization is adequate for lean mass [START_REF] Schoenau | The development of bone strength at the proximal radius during childhood and adolescence[END_REF].

Trabecular bone score TBS The TBS is an index which provides some information on the trabecular bone microarchitecture [START_REF] Bousson | & Groupe de Recherche et d'Information sur les Ostéoporoses (GRIO)[END_REF].

Table 3: Geometric indices of Beck [START_REF] Beck | Predicting femoral neck strength from bone mineral data. A structural approach[END_REF] and their clinical importance. FNW: femoral neck width; HAL: hip axis length.

Geometric indices of Beck

Limits of DXA

The nature of DXA scans is two-dimensional (2D), but the true nature of bone is threedimensional (3D) [START_REF] Carter | New approaches for interpreting projected bone densitometry data[END_REF][START_REF] Katzman | Clinical and anthropometric correlates of bone mineral acquisition in healthy adolescent girls[END_REF]. Thus, bone size is not taken into account by DXA. The strength of a bone depends on its volume; a larger volume vertebra will have a higher resistance than a smaller volume vertebra [START_REF] Beck | Measuring the structural strength of bones with dual-energy X-ray absorptiometry: principles, technical limitations, and future possibilities[END_REF]. DXA measures the area of the projection of a volume [START_REF] Beck | Measuring the structural strength of bones with dual-energy X-ray absorptiometry: principles, technical limitations, and future possibilities[END_REF]. Therefore, it may underestimate the value of BMD depending on the area of the measured volume. To solve this problem, mathematical formulas have been used to estimate volumetric BMD taking into account areal BMD and bone dimensions [START_REF] Katzman | Clinical and anthropometric correlates of bone mineral acquisition in healthy adolescent girls[END_REF]. These formulas calculate bone mineral apparent density (BMAD) which is an estimate of volumetric BMD.

Bone microarchitecture cannot be directly measured by DXA [START_REF] Cortet | TBS and bone strength[END_REF].

The trabecular bone score (TBS) is correlated to some micro-architectural parameters, but it is not considered a direct measure of it.

DXA scans do not distinguish between cortical bone and trabecular bone.

DXA does not distinguish between visceral fat mass and subcutaneous fat mass. These two types of fat have different effects on bone structure. In addition, DXA does not distinguish between brown fat and white fat which also have different effects on bone health. [START_REF] Ackerman | DXA surrogates for visceral fat are inversely associated with bone density measures in adolescent athletes with menstrual dysfunction[END_REF].

Theoretically, the subject's abdominal diameter should not exceed 60 to 65 cm. Thus, TBS

should not be measured in subjects with a BMI greater than 35 kg /m 2 .

The type of the DXA machine, the operator, and the positioning of the patient can change the BMD value (HAS, June 2006).

DXA does not take into account the possible infiltration of water or fat into the muscle; thus in an obese subject, the measurements may be falsified [START_REF] Horber | Impact of hydration status on body composition as measured by dual energy X-ray absorptiometry in normal volunteers and patients on haemodialysis[END_REF].

The estimate of muscle mass is not suitable for obese subjects who, in addition to having a large body fat, have an increased muscle mass. However, in proportion to their total body weight, their muscle mass (%) is actually low while in lean individuals, the muscle mass is proportionately higher.

The sample studied on which the reference measurements were made differ according to the brand of the device (the reference bases are used for the calculation of the T score) (HAS, June 2006).

DXA does not assess muscle functionality. Current devices are not suitable for patients who cannot move easily (resuscitation situation, etc).

In obese subjects, the measurements have technical limitations given the thickness of the soft tissue around the measurement areas (lumbar spine and hip), which can modify the precision of the measurements [START_REF] Bolotin | Inaccuracies inherent in patient-specific dual-energy X-ray absorptiometry bone mineral density measurements: comprehensive phantom-based evaluation[END_REF].

In old machines, the subject's weight is limited to 150 kg. These devices were not suitable for subjects with massive obesity [START_REF] Barbe | Composition corporelle[END_REF]. However, new DXA devices are more adapted to extreme obese subjects.

Physiopathology of osteoporosis

Osteoporosis could be classified into primary and secondary osteoporosis. There are two types of primary osteoporosis: type 1 and type 2 [START_REF] Dobbs | Osteoporosis[END_REF]. Secondary osteoporosis is related to factors like medical disorders or the use of some type medication [START_REF] Dobbs | Osteoporosis[END_REF].

Primary osteoporosis

Type 1 osteoporosis is found mostly in post-menopausal women because these women present low levels of oestrogens leading to the increase in bone resorption compared to bone formation thus accelerating bone loss [START_REF] Gallagher | Prevention and treatment of postmenopausal osteoporosis[END_REF]. Also, type 1 osteoporosis can be found in men. Type 1 osteoporosis in males might be caused by genetic factors involving genes for IGF-I [START_REF] Rosen | Association between serum insulin growth factor-I (IGF-I) and a simple sequence repeat in IGF-I gene: implications for genetic studies of bone mineral density[END_REF] or estrogen metabolism [START_REF] Van Pottelbergh | Perturbed sex steroid status in men with idiopathic osteoporosis and their sons[END_REF]. Also at this age, secondary osteoporosis might show.

Bone remodelling is a continuous self-regeneration process; it consists of removing old bones and replacing them with newer ones. Bone formation and resorption respectively by osteoblasts and osteoclasts help to maintain a balance in bone mass and strength to resist deformity. With aging, the balance between the formation and the resorption of bone is shifted favouring greater bone resorption and a lesser bone formation. This results in a decrease in bone mass and strength that results in type 2 osteoporosis [START_REF] Demontiero | Aging and bone loss: new insights for the clinician[END_REF].

Bone deterioration related to ageing is accelerated by the presence of several factors [START_REF] Pouresmaeili | A comprehensive overview on osteoporosis and its risk factors[END_REF]. These risk factors for osteoporosis can be divided into 2 categories: modifiable and non-modifiable factors shown in table 5 [START_REF] Pouresmaeili | A comprehensive overview on osteoporosis and its risk factors[END_REF]. [START_REF] Riggs | Evidence for two distinct syndromes of involutional osteoporosis[END_REF]. A decrease in trabecular bone mass is present in both sexes but to a higher rate in females. Before reaching 50 years, trabecular bone is reduced by 42% [START_REF] Riggs | A population-based assessment of rates of bone loss at multiple skeletal sites: evidence for substantial trabecular bone loss in young adult women and men[END_REF]. Therefore, type 1 osteoporosis affects trabecular bone more than cortical bone.

Middle-aged men who are affected by type 1 osteoporosis mainly show low BMD by DXA and vertebral fractures. On the other hand, cortical bone mass does not show any significant loss before midlife in both males and females. The loss is found in both sexes after the age of 50 [START_REF] Riggs | A population-based assessment of rates of bone loss at multiple skeletal sites: evidence for substantial trabecular bone loss in young adult women and men[END_REF]. Hence, cortical and trabecular bone loss are found in males and females affected by primary type 2 osteoporosis after the age of 50 causing fractures in numerous bone sites (vertebra, femur and radii). Men and women have different bone changes with aging. [START_REF] Khosla | Effects of sex and age on bone microstructure at the ultradistal radius: a population-based noninvasive in vivo assessment[END_REF] showed that with aging, men's trabeculae became thinner. Meanwhile, a loss and an increase in spacing of the trabeculae were only found in females. [START_REF] Christiansen | Mechanical contributions of the cortical and trabecular compartments contribute to differences in age-related changes in vertebral body strength in men and women assessed by QCT-based finite element analysis[END_REF] showed that while aging, the loss of cortical bone is superior in women than in men. At peak bone mass, men present larger bones compared to women. Therefore, less periosteal bone is found in long bones in women compared to men while aging [START_REF] Seeman | Pathogenesis of bone fragility in women and men[END_REF].

Secondary osteoporosis

In both sexes, secondary osteoporosis is common in some [START_REF] Ryan | Osteoporosis in men: the value of laboratory testing[END_REF] but not in all studies (Romagnoli et al., 2011); it is more shared in men than women [START_REF] Fitzpatrick | Secondary causes of osteoporosis[END_REF].

Hypogonadism, glucocorticoid usage, and immoderate alcohol consumption are mainly the causes of 85% of secondary osteoporosis occurrence in men [START_REF] Ebeling | Osteoporosis in men. New insights into aetiology, pathogenesis, prevention and management[END_REF][START_REF] Gagnon | Osteoporosis in men: its pathophysiology and the role of teriparatide in its treatment[END_REF]. It is shown that these three aspects were found most in younger men with osteoporosis (Orwoll and Klein, 2001). Table [START_REF] Alwan | Vitamin D and Trabecular Bone Score in a Group of Young Lebanese Adults[END_REF] shows many examples of secondary osteoporosis. Glucocorticoid usage causes osteoporosis and increases the risk of bone fracture that can be showed directly after 3 months of the beginning of the therapy [START_REF] Van Staa | Oral corticosteroids and fracture risk: relationship to daily and cumulative doses[END_REF].

Minimal attention is given by health care professionals regarding the increase in bone fracture related to glucocorticoid therapy in men compared to women [START_REF] Feldstein | Practice patterns in patients at risk for glucocorticoid-induced osteoporosis[END_REF].

Androgen deprivation therapy

Men going through androgen deprivation therapy (ADT) who had prostate cancer deserve attention from bone health professionals. ADT dramatically increases bone loss and bone fractures risk because of the low levels of some hormones (minimal serum levels of estradiol and testosterone) [START_REF] Smith | Obesity and sex steroids during gonadotropin-releasing hormone agonist treatment for prostate cancer[END_REF][START_REF] Bienz | Androgen-deprivation therapy and bone loss in prostate cancer patients: a clinical review[END_REF]. Only a minimal percentage of men are diagnosed and treated for osteoporosis that is caused by ADT.

Alcoholism

Optimal peak bone mass development in young people and the increase in bone loss in aged patients is adversely affected by long-term alcohol consumption. [START_REF] Ulhøi | Chronic Alcohol Abuse Leads to Low Bone Mass with No General Loss of Bone Structure or Bone Mechanical Strength<sup[END_REF][START_REF] Ganry | Effect of alcohol intake on bone mineral density in elderly women: The EPIDOS Study. Epidémiologie de l'Ostéoporose[END_REF][START_REF] Kim | Effect of chronic alcohol ingestion on bone mineral density in males without liver cirrhosis[END_REF][START_REF] Kizilgul | Bone health and vitamin D status in alcoholic liver disease[END_REF]. Heavy and chronic abuse of alcohol is significantly correlated with a decrease in BMD and bone fracture risk. However, in some studies, significant correlation was found between moderate intake of alcohol and high BMD, but in others nothing was detected [START_REF] Maurel | Alcohol and bone: review of dose effects and mechanisms[END_REF][START_REF] Jugdaohsingh | Moderate alcohol consumption and increased bone mineral density: potential ethanol and nonethanol mechanisms[END_REF][START_REF] Wosje | Bone density in relation to alcohol intake among men and women in the United States[END_REF]. In addition, the optimum quantity and frequency to produce beneficial effect of bone is not yet clear. Several studies had contradictory findings, depending on the selection of the subjects. Subjects' age, gender and, menopausal status affects the results of the studies. [START_REF] Maurel | Alcohol and bone: review of dose effects and mechanisms[END_REF] found that a similar quantity of alcohol consumption negatively affected bone in premenopausal women but positively affected it in postmenopausal women. But to be sure, a high consumption of alcohol will lead to bone loss and increase the risk of bone fractures.

1.4 Epidemiology of Osteoporosis: Worldwide, Europe, middle east and Lebanon

Worldwide

Osteoporosis is a foremost rising worldwide health issue [START_REF] Zaheer | Osteoporosis: Prevention and Treatment[END_REF]. Fragility osteoporosis fractures are some of the most well-known reasons for incapability, and they are considered significantly contributing to health care costs in numerous areas of the world. 200 million fractures worldwide are the result of osteoporosis [START_REF] Cooper | Hip fractures in the elderly: a world-wide projection[END_REF] which causes more than 9 million fractures each year (1 osteoporotic fracture every 3 seconds) (Johnel and [START_REF] Johnell | An estimate of the worldwide prevalence and disability associated with osteoporotic fractures[END_REF]. One over 3 women and one over 5 men above the age of 50 will encounter fractures related to osteoporosis in their lifetime. [START_REF] Melton | Bone density and fracture risk in men[END_REF][START_REF] Melton | Perspective. How many women have osteoporosis?[END_REF].

Hip fractures are considered to be the most serious of these fractures because they are correlated to a high rate of morbidity and mortality [START_REF] Zaheer | Osteoporosis: Prevention and Treatment[END_REF]. Half of the patients who had a hip fracture lose their capability to walk independently. Moreover, 33 % of men die in the first year after the presence of a hip fracture compared to 12 to 24 % of women [START_REF] Chrischilles | A model of lifetime osteoporosis impact[END_REF][START_REF] Magaziner | Excess mortality attributable to hip fracture in white women aged 70 years and older[END_REF][START_REF] Melton | Fractures attributable to osteoporosis: report from the National Osteoporosis Foundation[END_REF]. Vertebral fractures are most of the times asymptomatic and found when searching for other health problems. They are associated with many other problems involving loss in height, restrictive lung disease, back pain, kyphosis and movement impairment. Patients with vertebral fracture have five times more risk for having a new vertebral fracture and 2 times more risk to have other fragility fractures [START_REF] Zaheer | Osteoporosis: Prevention and Treatment[END_REF]. A decrease in 10% of vertebrae bone mass can multiply by 2 the risk of vertebral fractures. In addition, a decrease in 10% in hip bone mass can increase hip fracture risk by 2.5 (Klotzbueche et al., 2000). A 310% and a 240% increase in hip fractures numbers is predicted to be present by the year 2050 in men and women respectively compared to the numbers of the year 1990 [START_REF] Gullberg | World-wide projections for hip fracture[END_REF].

Europe

In 2010, an estimation of 27.6 million osteoporosis cases were present in Europe (Figure 4) [START_REF] Hernlund | Osteoporosis in the European Union: medical management, epidemiology and economic burden[END_REF]. Approximately 22 million women and 5 million men with osteoporosis were distributed across 27 countries in Europe (EU27) in 2010. The number of women with osteoporosis was 4 times higher than that of men. The highest osteoporosis numbers with an approximation of 5 million osteoporotic cases of which 1 million were men and 4 million were females were found in Germany (Table 7). Collectively, 21 % of women and 6.6 % of men (>50 years)

were the percentage of osteoporosis cases prevalent in all European populations [START_REF] Hernlund | Osteoporosis in the European Union: medical management, epidemiology and economic burden[END_REF]. In addition, thousands of female deaths were directly correlated with vertebral and other fractures in the EU27 countries. Also, an approximate of 9,000 deaths were associated to hip fracture in men. Fewer deaths resulted from vertebral and other fractures (table 8) [START_REF] Hernlund | Osteoporosis in the European Union: medical management, epidemiology and economic burden[END_REF].

Middle east and Lebanon

The rate of mortality due to hip fracture is considered high in the middle-eastern populations compared to the western populations. In western populations, the rate of mortality after hip fracture varies from 25 to 30 % while in the middle east and north Africa, this number is higher by 2 to 3 times [START_REF] Baddoura | Osteoporotic fractures, DXA, and fracture risk assessment: meeting future challenges in the Eastern Mediterranean Region[END_REF]. The availability of DXA scanners in the middle east region is limited. For example, in Morocco, for 1 million inhabitants, there are only 0.6 DXA machines (International Osteoporosis Foundation, 2011). The fracture incidence rates among people (> 50 years) are the lowest in Morocco (43.7 / 100,000 and 52.1/ 100,000 in men and women respectively) (El [START_REF] Maghraoui | Epidemiology of hip fractures in 2002 in Rabat, Morocco[END_REF]. Kuwait showed the highest rates of fracture risk (200 and 295 per 100,000 in men and women respectively) [START_REF] Azizieh | Fractures in Kuwait: incidence and distribution[END_REF]. Low concentrations of Vitamin D were found in the middle east and regardless of the presence of sunshine in this region, the highest rates of rickets were registered (International Osteoporosis Foundation, 2011).

A study done by [START_REF] Sibai | Hip fracture incidence in Lebanon: a national registry-based study with reference to standardized rates worldwide[END_REF] used data taken from the Lebanese ministry of health which represented 50 % of the Lebanese population showed that the crude rates of incidence of hip fractures for people aged (>50 years) across the 2 years of 2006 and 2008 were as follows: 164-188 in women and 80-107 in men per 100,000 per year. The age-adjusted incidence rates of hip fractures were between 329 to 370 in women and 110 to 134 in men per year per 100,000. These incidence rates were lower than the rates found in the US and northern Europe and close to rates found in southern Europe. Also, the age-adjusted incidence rates of hip fractures in Lebanon were close to those found in Spain and France in women, and close to those in Portugal, in France, Mexico and Thailand for men [START_REF] Sibai | Hip fracture incidence in Lebanon: a national registry-based study with reference to standardized rates worldwide[END_REF]. Another study done by Baddoura et al. (2001) showed that in Lebanon, the annual incidence of osteoporotic fractures is estimated at 2.6%. It is higher for women (3.8%) than for men (1.4%). The incidence per site is 0.4% for the hip, 0.4% for the forearm, 0.3% for the spine and 1.5% for "other" sites. The incidence is higher in women for all sites. The lifetime risk of osteoporotic fractures is estimated at 9.3% for men and 16.7% for women (Baddoura et al., 2001). These estimates were also lower than those of northern European countries but higher than those of Asian countries, suggesting a West-East gradient of risk factors (Baddoura et al., 2001). The prevalence of vertebral fractures in Lebanon is estimated at 19.9% for women and 12.0% for men [START_REF] Rafic | Vertebral fracture risk and impact of database selection on identifying elderly Lebanese with osteoporosis[END_REF].

Economic impact

The Ministry of Health (MOH) covers 50 %, the National Social Security Fund (NSSF) covers 25 %, the private insurances cover 12.5 % and the Co-ops, Army, Internal Security Forces cover 12.5% of the Lebanese medical care needs. According to the bulletin report from the WHO in 1999, direct hospital costs per person were estimated to be around 12000 $ in Australia to 8700 $ in Lebanon [START_REF] Delmas | Strong bones in later life: luxury or necessity?[END_REF]. This amount only represents the direct hospital charges. Nonetheless, it must be taken into consideration that the real cost of hip fractures could be 2 times higher than this amount due to additional care services.

Bone strength and fracture risk

From a mechanical viewpoint, structural failure of the bone leads to fractures. Fractures occur when the forces applied to the bone surpass its load-bearing capacity (Figure 7) [START_REF] Bouxsein | Determinants of skeletal fragility[END_REF]. Bone fracture is affected by the load that is applied to it. The load can vary depending on the direction and the magnitude of the applied force. For example, during a fall, the height, the direction of the fall (sideways, forward, backward), the type of the impact surface, the amount of soft tissue surrounding the bone and the ability of a person to react to the fall will affect the load applied on the bone and thus the fracture risk. [START_REF] Bouxsein | Biomechanics of Age-Related Fractures[END_REF]. In addition to these external factors, bone strength will affect the risk fracture. The ability of a bone to resist to applied loads is a function of three characteristics: the total mass, the geometric distribution of the mass, and the material properties (Figure 7) [START_REF] Cole | Whole Bone Mechanics and Bone Quality[END_REF]. BMD measurements by DXA reflect some of the components of bone strength, including bone mass. Bone mineral density (BMD), measured by DXA, is an important determinant of bone stiffness at any age [START_REF] Goulding | Overweight and obese children have low bone mass and area for their weight[END_REF]. It is strongly correlated with bone strength and can define approximately 70% of its variability [START_REF] Bouxsein | Determinants of skeletal fragility[END_REF]. BMD measurements are moderately to strongly correlated with the strength of human cadaveric vertebrae, radii and femurs. BMD remains the best determinant of bone mechanical strength.

Bone geometry also affects bone strength. Figure 9 shows how different bones with the same BMD can present different levels of bending and compression mechanical resistance depending on their dimensions and geometry [START_REF] Bouxsein | Determinants of skeletal fragility[END_REF].

Figure 9:

The effect of an increase in cortex diameter on bone compression and bending strength with no change in areal density [START_REF] Bouxsein | Determinants of skeletal fragility[END_REF].

Moreover, bone microarchitecture influences bone strength as well (Dalle [START_REF] Carbonare | Bone microarchitecture as an important determinant of bone strength[END_REF]. The parameters of the bone microarchitecture such as the number of trabeculae, the thickness of the trabeculae, the orientation trabeculae (giving the anisotropy of the structure), their degree of connectivity, as well as the spacing between them contribute to the stiffness of the bones without a significant increase in bone mass [START_REF] Bouxsein | Determinants of skeletal fragility[END_REF].

Therefore, a decrease in one or more of these parameters will lead to a decrease in trabecular bone strength. This is shown in figure 10, which shows that increasing the number of horizontal trabeculae increases trabecular bone buckling strength without any significant change in bone mass.

Peak bone mass

Definition of peak bone mass and prevention of osteoporosis

Peak bone mass (PBM) can be defined as "the amount of bony tissue present at the end of skeletal maturation" [START_REF] Bonjour | Peak bone mass[END_REF]. After attaining PBM in the first 30 years of life, a 0.3 % and a 0.5 % of bone loss per year is shown in men and women respectively. During the first year of menopause, an increase of 2 % in bone loss is shown (due to deficiency in estrogen). This fast loss in bone mass continues for a period of 6 years [START_REF] Dobbs | Osteoporosis[END_REF].

Because the bone loss that is related to aging is universal in both sexes, any factor that negatively affects reaching the maximum peak bone mass increases the chances of having fragility fractures related to osteoporosis later in life. Therefore, PBM is a strong predictor of osteoporosis later in life [START_REF] Specker | Rates of bone loss in young adult males[END_REF]. This is why increasing PBM during growth is an important strategy to prevent future osteoporosis cases. To prevent the occurrence of osteoporosis early in life, peak bone mass must be the highest possible because the higher the bone mass at baseline is, the less significant the decrease of bone mass related to aging will be to reach osteoporosis. But if the PBM is low and bone mass at baseline is not very high, future decrease in bone mass related to aging will lead to high risk of fracture and osteoporosis earlier in life (figure 11). A 10 % increase in PBM would decrease the risk of fragility fracture by a half in postmenopausal women [START_REF] Marshall | Meta-analysis of how well measures of bone mineral density predict occurrence of osteoporotic fractures[END_REF] and will delay the appearance of osteoporosis by thirteen years [START_REF] Hernandez | A theoretical analysis of the relative influences of peak BMD, age-related bone loss and menopause on the development of osteoporosis[END_REF]. On the other hand, a reduction of 6.4 % in bone mass during childhood is related to an increase by 2 times higher in fracture risk during adulthood [START_REF] Boreham | Physical activity in childhood and bone health[END_REF].

Figure 11:

Influence of PBM on the onset of osteoporosis later in life [START_REF] René | Maximizing bone mineral mass gain during growth for the prevention of fractures in the adolescents and the elderly[END_REF]).

Age gender and peak bone mass

The development of bone mass begins in foetal life, continues throughout childhood and ends in the end of the third decade of life [START_REF] Weaver | The National Osteoporosis Foundation's position statement on peak bone mass development and lifestyle factors: a systematic review and implementation recommendations[END_REF]. Age and sex affect bone growth evolution. Slow gain in bone mass is found in childhood. This gain significantly accelerates with puberty and then decelerates after it. (figure 12). The period of puberty (fast and strong bone growth) is very important and vital to reach PBM. [START_REF] Bailey | A Six-Year Longitudinal Study of the Relationship of Physical Activity to Bone Mineral Accrual in Growing Children: The University of Saskatchewan Bone Mineral Accrual Study[END_REF].

Difference in bone mass observed in adults in both sexes is first observed at puberty [START_REF] Bonjour | Peak bone mass[END_REF]. Before puberty, both sexes do not differ in bone mass. [START_REF] Theintz | Longitudinal monitoring of bone mass accumulation in healthy adolescents: evidence for a marked reduction after 16 years of age at the levels of lumbar spine and femoral neck in female subjects[END_REF] showed in their longitudinal study, a significantly noticeable increase in L2-L4 BMD and BMC and FN BMD from 11 to 14 years (3-year period) and an intense decrease after the age of 16 in adolescent females. After menarche, gain in bone mass dropped rapidly and became not significant (2 years later). In contrast, an increase in BMD and BMC was significantly high for both L2-L4 and mid-femoral from the age of 13 to 17 (4-year period) in adolescent males then decreased but remained significant until the age of 20 (3 years) at the lumbar level and at the level of the femoral shaft but not at the level femoral neck [START_REF] Theintz | Longitudinal monitoring of bone mass accumulation in healthy adolescents: evidence for a marked reduction after 16 years of age at the levels of lumbar spine and femoral neck in female subjects[END_REF].

Moreover, an increase in bone mass was only shown in men who were growing less than 1 cm per year and who reached pubertal age P5 [START_REF] Weaver | The National Osteoporosis Foundation's position statement on peak bone mass development and lifestyle factors: a systematic review and implementation recommendations[END_REF]. A higher increase in bone mass development in males compared to females was shown during the pubertal phase leading to an important difference between men and women. This is not due to a higher maximal gain in bone bass but to a longer pubertal maturation period [START_REF] Weaver | The National Osteoporosis Foundation's position statement on peak bone mass development and lifestyle factors: a systematic review and implementation recommendations[END_REF].

Determinants of peak bone mass

Peak bone mass is influenced by several factors (figure 13) (genetics, hormonal factors, mechanical factors, and nutritional factors).

Genetic factors

The role of genetic factors in the pathophysiology of osteoporosis has been confirmed by several authors [START_REF] Jean-Philippe | The importance and relevance of peak bone mass in the prevalence of osteoporosis[END_REF][START_REF] Eisman | Genetics of osteoporosis[END_REF]. A significant correlation between the BMD of mothers and daughters has been found before the start of pubertal maturation phase [START_REF] Jean-Philippe | The importance and relevance of peak bone mass in the prevalence of osteoporosis[END_REF][START_REF] Duren | Quantitative genetics of cortical bone mass in healthy 10-year-old children from the Fels Longitudinal Study[END_REF]. 60 to 80 % of bone mass variability may be influenced by genetic factors [START_REF] Eisman | Genetics of osteoporosis[END_REF]. On the other hand, the other controlled factors such as the environmental factors are thought to account for 20 to 40 percent of BMD.

Lumbar spine BMD (rich in trabecular bone) in greatly influenced by genetic factors compared to femoral neck BMD (rich in cortical bone) that is more affected by mechanical factors.

Hormonal factors

Growth hormone (GH), IGF-1 and sex hormones play an essential role in the growth and the capability to achieve optimal PBM [START_REF] Locatelli | Effect of GH/IGF-1 on Bone Metabolism and Osteoporsosis[END_REF]. Growth hormone insufficiency causes a decrease in bone mass in children and an increased risk of fracture in adults [START_REF] Giustina | Growth Hormone, Insulin-Like Growth Factors, and the Skeleton[END_REF].

In children, bone growth is primarily regulated by GH and IGF-1. IGF-1 mediates GH. A positive correlation between IGF-1 and BMD is observed in both sexes. A strong association is found between the decrease of the levels of these hormones and the increase of risk factures related to osteoporosis regardless of BMD [START_REF] Garnero | Low serum IGF-1 and occurrence of osteoporotic fractures in postmenopausal women[END_REF]. In adolescents, sex hormones are thought to have the greatest influence on bone metabolism [START_REF] Bass | Risk-adjusted mortality rates of elderly veterans with hip fractures[END_REF][START_REF] Rizzoli | Osteoporosis, genetics and hormones[END_REF]. Sex steroids are responsible for the skeletal dimorphism that appears during and after adolescence [START_REF] Compston | Sex steroids and bone[END_REF]. The role of estrogen is particularly important during the puberty phase [START_REF] Riggs | Sex steroids and the construction and conservation of the adult skeleton[END_REF]. Estrogen resistance and aromatase deficiency in men induce growth retardation and may delay attainment of maximum height despite the presence of normal testosterone levels [START_REF] Bilezikian | Increased bone mass as a result of estrogen therapy in a man with aromatase deficiency[END_REF]. Estrogen insufficiency is a critical element in the pathogenesis of osteoporosis in both sexes [START_REF] Locatelli | Effect of GH/IGF-1 on Bone Metabolism and Osteoporsosis[END_REF].

Testosterone explains the differences between the sexes in terms of bone geometry (longer growth and better periosteal apposition in boys compared to girls). In late adolescence, both BMC and areal BMD are superior in boys compared to girls [START_REF] Riggs | Sex steroids and the construction and conservation of the adult skeleton[END_REF].

Androgens and estrogens positively affect bone mass in both sexes [START_REF] Locatelli | Effect of GH/IGF-1 on Bone Metabolism and Osteoporsosis[END_REF]). Men's bones are larger in size, diameter and cortical thickness than those of women. This is a biomechanical advantage for men in whom the incidence of fractures is low compared to women [START_REF] Compston | Sex steroids and bone[END_REF] 2.3.3 Nutritional factors

Calcium intake

Several correlation studies in children and adolescents have been carried out between daily calcium consumption and bone mass [START_REF] René | Maximizing bone mineral mass gain during growth for the prevention of fractures in the adolescents and the elderly[END_REF]. Most of these studies done on different populations showed a significant correlation between daily calcium intake and bone mass [START_REF] René | Maximizing bone mineral mass gain during growth for the prevention of fractures in the adolescents and the elderly[END_REF]. The effect of calcium supplementation on height, BMC, and BMD at several bone sites has been investigated in several prospective studies [START_REF] René | Maximizing bone mineral mass gain during growth for the prevention of fractures in the adolescents and the elderly[END_REF]. The gains in BMC and BMD were greater in those who took calcium supplements compared to controls. Two meta-analyses confirmed the beneficial effect of calcium-rich products on bone mass during growth [START_REF] Huncharek | Impact of dairy products and dietary calcium on bone-mineral content in children: results of a meta-analysisDatabase of Abstracts of Reviews of Effects (DARE): Quality-assessed Reviews [Internet[END_REF][START_REF] Winzenberg | Effects of calcium supplementation on bone density in healthy children: meta-analysis of randomised controlled trials[END_REF]).

Protein intake

Protein intake provides the human body with the amino acids necessary for the construction of the bone matrix [START_REF] René | Maximizing bone mineral mass gain during growth for the prevention of fractures in the adolescents and the elderly[END_REF]. Protein intake is an essential factor for bone growth since it influences the secretion of IGF-1 [START_REF] René | Maximizing bone mineral mass gain during growth for the prevention of fractures in the adolescents and the elderly[END_REF]. Proteins can therefore modulate the genetic potential of peak bone mass. Low protein intake can adversely affect bone mass by reducing the production of IGF-1. The beneficial effects of protein intake on BMC and BMD have been demonstrated in cross-sectional and longitudinal studies [START_REF] René | Maximizing bone mineral mass gain during growth for the prevention of fractures in the adolescents and the elderly[END_REF]).

Vitamin D

Vitamin D has positive effects on the skeleton. Physiologically, it stimulates the intestinal absorption of calcium. This vitamin has a fundamental role in phosphocalcic homeostasis and therefore in the process of bone growth. In the elderly, insufficient vitamin D increases the risk of osteopenia and osteoporosis. At the epidemiological level, the NHANES study showed the existence of a positive correlation between plasma vitamin D concentration and BMD in subjects whose values ranged from 22.5 to 94 nmol / L [START_REF] Bischoff-Ferrari | Positive association between 25-hydroxy vitamin D levels and bone mineral density: a population-based study of younger and older adults[END_REF]. A meta-analysis published in 2007 showed that vitamin D and calcium supplementation are important for the prevention of osteopenia and osteoporosis [START_REF] Tang | Use of calcium or calcium in combination with vitamin D supplementation to prevent fractures and bone loss in people aged 50 years and older: a meta-analysis[END_REF]. On the other hand, several studies have shown that an increase in muscle weakness and an increase in the risk of falls are associated with a deficit in vitamin D [START_REF] Bischoff-Ferrari | Relevance of vitamin D in muscle health[END_REF][START_REF] Janssen | Vitamin D deficiency, muscle function, and falls in elderly people[END_REF][START_REF] Girgis | Effects of vitamin D in skeletal muscle: falls, strength, athletic performance and insulin sensitivity[END_REF].

Physical activity

Growing bones respond better to mechanical stress than adult bones. The practice of physical activities induces an increase in BMC and BMD in children and adolescents. This effect appears to be greater before and at the start of the puberty phase than after this phase [START_REF] Santos | Exercise and bone health across the lifespan[END_REF]. Exercising during childhood and adolescence is very important even after their termination [START_REF] Santos | Exercise and bone health across the lifespan[END_REF]. The timing of the initiation of the physical activity may be also important. A recent study showed that bone strength of adult individuals is affect ed by the age at which they started to walk [START_REF] Ireland | Later Age at Onset of Independent Walking Is Associated With Lower Bone Strength at Fracture-Prone Sites in Older Men[END_REF]. This study also showed that a lower BMC (at the spine, hip and radius) was found in men that started to walk at a late age in their childhood compared to those men who started walking at an earlier age. Another systematic review showed that performing weight-bearing activities such as football, gymnastics and jumping during childhood positively affects bone strength while increasing bone mineral growth in pre and peri-pubertal children (MacKelvie et al. 2002). These results

were also supported by a newer systematic review that studied the effect of weight bearing exercises and bone mineral gain in children and adolescents [START_REF] Hind | Weight-bearing exercise and bone mineral accrual in children and adolescents: a review of controlled trials[END_REF].

Body weight

Body weight and BMI are positive determinants of BMD of load -bearing bones in both sexes [START_REF] Ian | Fat and bone[END_REF]. The gain in body mass is associated with an increase in BMD values while its loss induces a decrease in its values [START_REF] Shapses | Bone Metabolism in Obesity and Weight Loss[END_REF].

Bone adaptation to exercise

The main function of the skeleton is to support muscles to allow posture and movement in the space. Bone size, shape and rigidity are adapted to the habitual loads performed on it.

Physical exercise leads to bone adaptation to a higher load compared to the habitual load.

This procedure is regulated by cellular mechanotransduction [START_REF] Goodman | Bone and skeletal muscle: Key players in mechanotransduction and potential overlapping mechanisms[END_REF]. During exercise, the new load of the exercise deforms the bone; this will lead to an alteration in the original conformation of the mechanosensors that are located throughout the cell such as integrins and stretch activated ion channels [START_REF] Guilluy | Isolated nuclei adapt to force and reveal a mechanotransduction pathway in the nucleus[END_REF][START_REF] Ross | Integrins in mechanotransduction[END_REF]. A proper biochemical reaction is stimulated by this change through a flood of signals. Thus, bone formation and osteogenesis is present at bone sites that are deformed by the activity.

A signalling cascade is elicited by this change to produce a suitable biochemical response such as osteogenesis and bone accretion at the site of deformation [START_REF] Goodman | Bone and skeletal muscle: Key players in mechanotransduction and potential overlapping mechanisms[END_REF].

Habitual load to bone principally comes from muscle contraction and gravity. In addition, physical exercise also puts the bone under a mechanical stress that is higher than the habitual load exerted by muscle contraction and the gravitational load (impact with the ground).

Gravitational loads

Gravitational loads are reactive loads that are the result of a contact between a weighted object (human body) and another object or substrate (ground) (Judex and Carlsonl, 2009).

Gravitational loads are measured via ground reaction forces. These forces are the result of body mass (body weight) and the acceleration of the movement. During a high impact sport, such as gymnastics, a jump might have a ground reaction forces up to ten to twenty times of body weight. On the other hand, low impact activity such as walking has a ground reaction force almost similar to body weight (Judex and Carlsonl, 2009).

Gravitational load has a strong effect on bone health which is obvious by the noticeable decrease in bone mass in a weightless environment situation. For example, a decrease of 1 % in bone mass per week was observed in astronauts during their space flight. This loss is found to be the greatest in weight-bearing sites [START_REF] Lang | Cortical and trabecular bone mineral loss from the spine and hip in long-duration spaceflight[END_REF].

Similarly, bone loss was accelerated during the period of bed rest [START_REF] Kohrt | Muscle forces or gravity: what predominates mechanical loading on bone?[END_REF]. Thus, these findings from space flight and bed rest studies showed that gravitational loading is necessary to preserve BMD at weight-bearing sites.

In real life situations, the majority of physical exercise stimulates both muscle contraction and gravitational loading forces on the skeleton. Therefore, it is very hard to isolate one form from the other. Cycling and swimming are non-weight bearing sports but involve muscle contraction forces on the bones. Many studies compared BMD of swimmers and cyclists to non-athlete controls and to weight-bearing athletes. They found that BMD values of the control group were significantly higher than those of swimmers and cyclists even after controlling for changes in lean mass or in body weight. Another study showed that cyclists had similar BMD compared to controls; however, weight lifters and runners had significantly higher BMD [START_REF] Rector | Participation in road cycling vs running is associated with lower bone mineral density in men[END_REF][START_REF] Fehling | A comparison of bone mineral densities among female athletes in impact loading and active loading sports[END_REF][START_REF] Nichols | Low bone mineral density in highly trained male master cyclists[END_REF][START_REF] Stewart | Total and regional bone density in male runners, cyclists, and controls[END_REF][START_REF] Sabo | Bone quality in the lumbar spine in highperformance athletes[END_REF][START_REF] Warner | Bone mineral density of competitive male mountain and road cyclists[END_REF][START_REF] Heinonen | Bone mineral density of female athletes in different sports[END_REF].

Athletes who participated in sports that apply high impact loads on the skeleton such as gymnastics, volleyball and soccer have a higher BMD and stronger skeleton compared to controls [START_REF] Orwoll | Osteoporosis in Men: The Effects of Gender on Skeletal Health[END_REF]. Moreover [START_REF] Creighton | Weight-bearing exercise and markers of bone turnover in female athletes[END_REF] found that athletes who participated in sports that apply the highest impact loads on the skeleton (such as basketball and volleyball) have the highest BMD and the highest markers of bone formation compared to athletes who participated in sports that apply moderate impact load on the skeleton (such as soccer and track) and to athletes that participated in non-bearing activities (such as swimming) and sedentary controls. Athletes of high and moderate impact load had higher hip BMD compared to athletes of non-impact sport and sedentary controls. The non-impact sport athletes were similar to the sedentary controls regarding BMD. Therefore, gravitational load exerted by impact sports may induce bone formation and enhance osteogenesis at weightbearing skeleton sites.

Muscle Contraction Forces

It is recognised that bone adapts to the mechanical stress that is applied to it. Muscle contraction applies mechanical stress to the bone. This is found by corresponding changes in both muscle strength and bone size [START_REF] Robling | Is bone's response to mechanical signals dominated by muscle forces[END_REF][START_REF] Daly | The relationship between muscle size and bone geometry during growth and in response to exercise[END_REF]. [START_REF] Daly | The relationship between muscle size and bone geometry during growth and in response to exercise[END_REF] compared the BMD of the dominant arm of a tennis player to the nondominant arm. They found that the dominant arm has higher muscle and bone mass compared to the other arm. This suggests that muscle contraction is associated to an increase in bone and muscle mass. [START_REF] Rector | Lean body mass and weight-bearing activity in the prediction of bone mineral density in physically active men[END_REF] found that muscle mass of athletes who perform resistance training exercises for all major muscle groups (lower and upper body) was positively correlated to arm BMD, leg BMD, hip BMD and lumbar spine BMD. This proposes that there is a positive correlation between muscle mass and BMD of the arm (a non-weight bearing site) which highlights how muscle contraction without gravitational forces contributes to an increase in muscle mass that is correlated to an increase in BMD.

In addition, [START_REF] Carter | Exploring the relationship between changes in bone mineral density, lean body mass, and hormones in active, adult males with osteopenia after a 12-month exercise intervention[END_REF] WB (8.1%, 7.7% and 6.2% respectively) compared to non-active controls. Moreover, BMC benefits remained after 3 years of the end of the intervention with a continuous BMC increase of 7 to 8% in FN and TH [START_REF] Meyer | 3-Year follow-up results of bone mineral content and density after a school-based physical activity randomized intervention trial[END_REF]. Among the choices of exercises, walking had a minimal positive effect on BMD because of its low impact nature and the minimal mechanical load that it exerts on the bones. This is supported by a recent systematic review by MacKelvie et al. (2002) that presented the effect of weight-bearing exercises on bone strength in children before and at puberty. On the other hand, strength training and high impact activities had additional effects on the prevention of bone loss [START_REF] Gómez-Cabello | Effects of training on bone mass in older adults: a systematic review[END_REF]. In addition to the effect of exercise on children, systematic reviews by [START_REF] Hamilton | The effects of exercise and physical activity participation on bone mass and geometry in postmenopausal women: a systematic review of pQCT studies[END_REF] and [START_REF] Bolam | The Osteogenic Effect of Impact-Loading and Resistance Exercise on Bone Mineral Density in Middle-Aged and Older Men: A Pilot Study[END_REF] showed that bone loading exercises have a beneficial effect on bone creation in middle-aged persons but in a smaller degree compared to children and adolescents [START_REF] Hind | Weight-bearing exercise and bone mineral accrual in children and adolescents: a review of controlled trials[END_REF][START_REF] Nogueira | Exercise to improve pediatric bone and fat: a systematic review and meta-analysis[END_REF]. According to [START_REF] Heinonen | Randomised controlled trial of effect of high-impact exercise on selected risk factors for osteoporotic fractures[END_REF], practicing a high impact sport for a duration of 18 months performed by 35 to 45-year pre-menopausal women produced gradual increase in femoral neck BMD. Inactive controls did not show any BMD changes. In addition, a meta-analysis showed that different exercise regimes lasting for a period of 24 weeks increase FN and lumbar spine BMD [START_REF] Kelley | Exercise and bone mineral density in premenopausal women: a meta-analysis of randomized controlled trials[END_REF]. Studies investigating the effect of exercise on bone health in older people (>50 years) were less compared to children and adolescents. Weight bearing activities are effective in preserving bone mass in older individuals. [START_REF] Maddalozzo | High intensity resistance training: effects on bone in older men and women[END_REF] showed that high intensity training or moderate strength training for a 6-month period in men and women ( 50years) increased spine BMD by 1.9 % in men, while women did not show any increase. In addition, a longer training duration of 12 months resulted in an increase in the geometry, BMD and BMC of the FN in elderly men aged between 65 to 80 years [START_REF] Allison | High impact exercise increased femoral neck bone mineral density in older men: a randomised unilateral intervention[END_REF]).

Principles of the American College of Sports Medicine

In order to achieve significant bone gains and induce osteogenic effect, the following principles should be taken into consideration while planning physical training programs [START_REF] Kohrt | Physical Activity and Bone Health[END_REF]:

Specificity: Only the bone sites associated to mechanical stresses undergo a positive bone adaptation.

Overload: An osteogenic response only takes place when the load exerted on the bone exceeds the habitual load that is imposed on it. A gradual increase in load or an overload is required to achieve this response.

Reversibility: If sports practice is interrupted or stopped, its positive effects on BMD do not persist. The volume and intensity of practice that maintains BMD remains to be determined.

Start-up capital:

In general, the higher the baseline BMD of a subject is, the lower the benefits associated with physical training will be low. The lower a subject's baseline BMD is, the higher the benefits associated with physical training will be high.

Trainability:

The maximum achievable BMD is affected by genetic factors and varies widely among individuals. This "ceiling" value determines the potential progress of each individual.

3.5 Principles of Burr, Robling and Turner [START_REF] Burr | Effects of biomechanical stress on bones in animals[END_REF] talked about 3 general rules that are related to the osteogenic adaptation to physical training:

Dynamic stresses generate a positive bone response unlike static stresses.

The relationship between the duration of the application of mechanical stresses and the osteogenic response is not linear. An excessive and prolonged duration of exercise can in some cases decrease the osteogenic response. Recovery between exercises (a few minutes) or between 2 training sessions (4 to 8 hours) is very important to optimize bone responses.

The bone response is superior after exercising with high biomechanical stress of a short duration than after exercising with low impact stress with high duration. Bone tissue quickly gets used to the type and intensity of exercise. Variation is very important to ensure not hitting a plateau. In practice, in order to avoid a stagnation of the bone response, it is necessary to change the type and intensity of exercise and increase the level of mechanical stress in the workouts performed.

Soccer and bone

Effects of soccer training on different bone parameters in males aged between 8 to 16 years

As mentioned in the previous chapters, PBM is considered as an important predictor of osteoporotic fractures later in the lifespan. Several studies showed that exercise interventions in children and adults are beneficial for bone growth and help to reach a higher PBM (Lívia Santos et al 2017). Many studies investigated the effect of soccer training on bone mass and showed that soccer training is beneficial for improving many bone parameters in children and adolescent males. Table 9 summarizes several longitudinal studies related to long soccer practice and its effect on bone health. After the 3-year period, soccer players compared to control showed:

-higher BMC in the legs andhigher BMD in all boneloaded regions -higher femoral neck and intertrochanteric BMC.

A long duration of soccer training (3 years) beginning at a pre-pubertal age showed a greater gain in bone mass compared to aged matched physically active controls. DXA was used to measure BMD and BMC at different sites pre and post intervention After 3 years: Soccer players had: higher BMD higher BMC at all weightbearing-sites compared to controls.

-no significant difference in between groups for BMD and BMC of the head and arms.

Soccer training for a 3-year duration in pubertal boys showed a significant gain in BMD and BMC in weight bearing sites. -Significant changes were not shown for BMC.

-Higher level of performance was found in the SG compared to CG for YY-IE2 test.

SG exhibited higher PTE and PTF compared to CG.

Soccer practice has a positive effect on the muscle-skeletal structures in young males.

Effects of soccer training on several bone parameters in males aged between 20 and 54 years

Being physically inactive can lead to bone loss and could increase the risk of osteoporotic fractures. Increasing activity levels during any period throughout the lifespan will help to decrease the risk of bone loss thus decreasing the risk of osteoporotic fractures [START_REF] Carter | Physical Activity and Bone Health[END_REF].

Several studies investigated the effects of soccer on bone health (table 10). [START_REF] Krustrup | Recreational soccer is an effective health-promoting activity for untrained men[END_REF] showed that a 12-week period of recreational football in men aged 20-43 years improved bone leg mass, whereas another study conducted by [START_REF] Peter | Soccer improves fitness and attenuates cardiovascular risk factors in hypertensive men[END_REF] showed that a 6-month period of soccer training in men aged between 31 and 54 years did not show any increase in bone mass but reduced blood pressure and improved aerobic fitness. Moreover, [START_REF] Andersen | A preliminary study: effects of football training on glucose control, body composition, and performance in men with type 2 diabetes[END_REF] showed that regular football training also did not increase bone mass but did help to maintain bone mass in middle aged men with T2DM. Summary of several studies are shown in table 2. Many studies investigated the influence of soccer on bone health in elderly men. Helge et al. (2014) showed that a 4-month period of soccer training had a beneficial effect on bone formation and an additional benefit was observed after 12 months. In addition to healthy elderly men, soccer training in men with prostate cancer undertaking therapy showed an increase and a preservation of BMD at many bone sites. These studies are represented in table 11. Compared with the nonactives:

Soccer players had significantly higher BMD of the:

-total body (2.7%) -lumbar spine (6.1%)

-the dominant and nondominant hip (all sites).

The largest differences were found in the greater trochanter on both sides (dominant, 16.5%, nondominant, 14.8%).

The soccer players had significantly higher Soccer practice in adolescent females is associated with high bone mass in weight-bearing sites.

concentric and eccentric peak torque of the thigh muscles.

4.6 Cross-sectional studies related to male soccer players and inactive controls aged between 18 and 30 years

Several cross sectional studies were conducted on male soccer players and inactive aged matched controls. BMD in many sites, especially in weight bearing sites, was significantly higher in soccer players compared to controls (table 14). Soccer training seems to have a beneficial site specific effect on BMD in males aged between 18 to 30 years. In addition to BMD, geometric indices of hip bone strength are found to be higher in soccer players compared to controls (El [START_REF] Hage | Composite indices of femoral neck strength in adult female soccer players[END_REF]. -Participants in rugby, soccer, other team sports and fighting sports had a high TB BMD and high leg BMD -For head BMD, there was no statistical difference among the different groups.

-soccer player and runners had a higher leg ratio; bodybuilders, fighters, climbers and swimmers had a higher arm ratio; rugby players had a higher spine ratio.

BMD and ratio differences between several sports seem to be sitespecific and are created by the nonhabitual load exerted by the sport on specific sites of the skeleton by muscle contractions and gravitational loads. Soccer players have lower body fat % and higher lean mass and bone mass compared to inactive controls. 4.7 Cross sectional studies related to male soccer players and inactive controls aged between 10 to 17 years Several cross-sectional studies were conducted on male soccer players and inactive aged matched controls. BMD in many sites, especially in weight bearing sites, was significantly higher in soccer players compared to controls (table 15). Soccer training seems to have a beneficial site specific effect on BMD in males aged between 10 to 17 years. 23 soccer players (11 male) 20 swimmers (10 male) 25 controls (12 male) ages 13 to 17 years Densitometric measurement at the right os calcis was the site selected was performed A standard SPA protocol was used to determine the BMC of many sites.

-the lowest os calcis density in both sexes was found in swimmers -whereas the soccer players had the highest bone density at this weight-bearing site -No differences in the distal radius BMC were observed among the group or between sexes.

Soccer training is associated with an increase in BMC values at weightbearing sites in young males. Futsal players had significantly higher aBMD and aBMC at the lumbar spine, -pelvis and lower limbs compared to SG and CG. . Futsal, as a weight-bearing and a high-impact sport has a beneficial effect on bone formation in males during childhood and adolescence. The football players showed enhanced trochanteric BMC.

Football players showed higher femoral and lumbar spine BMD compared to controls.

Football training helps to increase many physical parameters, improves body composition and bone mass in weight-bearing sites in pre-pubertal boys.

Cross sectional studies related to female soccer players and inactive controls aged between 10 to 18 years

Several cross sectional studies were investigated on female soccer players and inactive aged matched controls. BMD in many sites, especially in weight bearing sites, was significantly higher in female soccer players compared to controls (table 16). Soccer training seems to have a beneficial site specific effect on BMD in females aged between 10-18 years. -No difference between weight-lifters and swimmers.

-BMD of soccer players were significantly higher than adult norms compared to normative data from the WHO.

-BMD of swimmers were significantly lower than adult females.

Soccer participation in adolescent females has a beneficial effect on BMD.

Pettersson at al. (2000)

50 female participated in this study and were divided into: BMD (g/cm(2)), BMC (g), and bone area (cm(2)) of many sites were measured Both skipping and soccer participants had significantly higher BMD (P < 0.05) at Soccer training and rope skipping have a beneficial effect on bone mass at weight-bearing sites.

Participated in this study

Body composition and total body, lumbar spine and proximal femur BMD were measured by DXA.

Football players had significantly higher BMD than controls at all sites measured.

The proximal femur sites (10.5-11.1%) had the greater differences in BMD compared to lumbar spine (4.8%) or the total body (3.5%).

Greater differences were found for senior than for juniors.

Soccer training had a site-specific beneficial effect on bone formation in female players.

4.9 Cross-sectional studies related to male soccer players and inactive controls aged between 50 years and older Former football practice is associated with higher BMD at different sites compared to aged matched controls (table 17). In addition, composite indices of femoral neck strength were found to be higher in former football players compared to their aged matched controls (Finianos et al., 2020). Former football practice is associated with high bone mineral density in weight-loaded sites.

To summarize, the current literature review included several chapters related to osteoporosis, concepts of bone strength and peak bone mass, bone response to exercise and the effects of soccer practice on bone mineral density, bone geometry and other bone health parameters.

Other than medication, physical exercise is an effective strategy to improve body balance and bone health and to diminish the risk of falls and bone fractures [START_REF] Schwab | Nonpharmacological approaches to improve bone health and reduce osteoporosis[END_REF].

The fact that physical exercise could be done without high costs and with minimal side effects renders it easily applicable [START_REF] Schwab | Nonpharmacological approaches to improve bone health and reduce osteoporosis[END_REF]. Being physically inactive leads to bone loss and could increase the risk of osteoporotic fractures. Increasing activity levels during any period throughout the lifespan could help to decrease the risk of bone loss, thus decreasing the risk of osteoporotic fractures [START_REF] Carter | Physical Activity and Bone Health[END_REF]. Lately, osteoporosis has been classified as a health problem mainly related to the female population. However, recent studies are trying to comprehend the effects and the causes of osteoporosis on men (Madeoet al., 2007). Bone loss will occur with aging in both sexes [START_REF] Demontiero | Aging and bone loss: new insights for the clinician[END_REF], and one over 5 men above the age of 50 will encounter fractures related to osteoporosis in their lifetime [START_REF] Melton | Bone density and fracture risk in men[END_REF]. It is never too late to start practicing physical activity at the age of 50 years. In the contrary, it is a suitable time to prevent the normal loss of bone associated with aging. Knowing that the majority of Lebanese 50-year-old men are not used to doing physical activities due to the lack of school's physical education programs in that period of time characterised by conflicts and economic collapse related to civil wars, they tend to neglect the importance of physical activities on health. Moreover, hip fractures are considered to be the most serious of fractures because they are correlated to a high rate of morbidity and mortality [START_REF] Zaheer | Osteoporosis: Prevention and Treatment[END_REF]. Half of the patients who had a hip fracture lose their capability to walk independently. So, it is important to incorporate strategies that help to prevent this type of fracture. Physical activity could be beneficial to increase bone mass and to prevent its loss. The choice of physical activity is very important, because some types of physical activities (high impact: running, soccer, gymnastics and volleyball) are superior to others (swimming and cycling) in positively affecting bone formation [START_REF] Kohrt | Physical Activity and Bone Health[END_REF]. Therefore, soccer is considered as a high-impact weightbearing sport, and many studies showed that its practice increases bone formation at several sites (shown previously in the tables). Furthermore, football is dispersed everywhere in t he world, and it is considered as being one of the sports with the highest number of enrolment in participants and players [START_REF] Dvorak | Football is the most popular sport worldwide[END_REF]. Soccer participation is enjoyable and fun with moderate feeling of physical fatigue after its practice [START_REF] Peter | Football is medicine: it is time for patients to play![END_REF]. It helps to build new friends with different socio-economic backgrounds and creates social relationships. This will help to decrease the stress of life, and it positively affects mental and social health. However, all soccer related studies (chapter of bone and soccer) had a training time ranged between 45 to 60 minutes, 2 to 3 times per week. Middle-aged Lebanese people have many responsibilities due to the economic crisis, and the majority of them do not have plenty of time (2-3 x 60 min) to practice sport; therefore, creating a time efficient soccer training intervention should be investigated.

The aim of the study was to know the effectiveness of a 1-year recreational football protocol on bone mineral density and physical performance parameters in a group of healthy inactive 50-year-old men.

This PhD study will allow us to:

-Detect the effects of a short volume of recreational football (RF30: 2 times 30 min mini football game per week) on bone mineral density and physical parameters in a group of healthy inactive 50-year-old men.

-Compare the effects of two recreational football protocols (RF30: 2x30min vs RF60: 2x60min for 1 year) on bone mineral density and physical performance parameters.

-To know the effectiveness of a 1-year recreational football protocol on bone mineral density and physical performance parameters in a group of healthy 50-year-old men who played football regularly in the past 5 years and are still playing football till today.

The present thesis is based on several hypotheses:

-Recreational football increases bone mineral density and enhances physical performance parameters in both groups (RF60 and RF30).

-2x30 min/week of recreational football is sufficient to increase bone mineral density and enhance physical performance in healthy 50-year-old men.

-Former football players have higher bone mineral density and higher physical performances before starting the intervention compared to the inactive participants.

-Muscular power, sprinting performance and VO2 max are positively correlated to bone health parameters in healthy middle-aged men.

GENERAL METHODOLOGY

1. Subjects 51 middle-aged men voluntarily participated in our PhD study. They were randomly recruited from Zgharta, a city located in North Lebanon. All subjects were healthy men aged between 41 and 58 years. They were non-smokers and had no history of major orthopedic problems or other disorders that affect bone metabolism including diabetes. Subjects with any med ical condition likely to affect bone metabolism including history of chronic disease with vital organ involvement or intake of medications that may affect bone metabolism were excluded.

All subjects were well informed about the objective of the study including the risks and benefits of participation. Written informed consent was signed by all subjects before participating in the study. The work described has been carried out in accordance with the declaration of Helsinki (regarding human experimentation developed for the medical community by the World Medical Association).

Anthropometric measurements

Body weight was measured using a standard mechanical scale with a precision of 0.1 kg.

Height was measured in a vertical position to the nearest 0.5 cm using a standard stadiometer. BMI was calculated by dividing body weight to the height squared (kg/m2). Body composition including lean mass (kg), fat mass (kg) and body fat percentage (FM; %kg) was also assessed by using dual-energy X-ray densitometry (DXA; GE-Lunar iDXA, Madison, WI).

Bone measurements

BMC and BMD were assessed by DXA (DXA; GE-Lunar iDXA, Madison, WI). Geometric indices of femoral neck were calculated by the device according to the method of [START_REF] Beck | Predicting femoral neck strength from bone mineral data. A structural approach[END_REF]. Geometric indices of femoral neck strength (CSI, BSI and ISI) were calculated using the method of [START_REF] Karlamangla | Hip fracture risk assessment using composite indices of femoral neck strength: the Rancho Bernardo study[END_REF].

Physical performance measurements

Time of the 10-m sprint, vertical jump height, horizontal jump distance, maximum power of the lower limbs, maximal oxygen consumption,1-RM Half-squat, 1-RM bench press and handgrip maximal isometric strength have been tested. More details concerning these tests are listed in study 1.

Validated questionnaires

Daily calcium consumption, daily protein consumption, the weekly volume of physical activity and the assessment of sleep quality and disturbances were evaluated by validated questionnaires [START_REF] Buysse | The Pittsburgh Sleep Quality Index: a new instrument for psychiatric practice and research[END_REF][START_REF] Fardellone | Evaluation of the calcium content of diet by frequential self-questionnaire[END_REF][START_REF] Morin | A rapid selfadministered food frequency questionnaire for the evaluation of dietary protein intake[END_REF][START_REF] Armstrong | Development of the World Health Organization Global Physical Activity Questionnaire (GPAQ)[END_REF].

Football training

The first 2 studies were cross-sectional in nature. Study 3 was longitudinal. In this study, the training lasted for 1 year with 2 training sessions per week. 2 experimental groups (RF60 and RF30) were present in this study. For the RF60 group, participants played normal minifootball games 2 times per week for 60 min in total. For the RF30 group, participants also played mini football games 2 times per week for 30 min in total. More details are found in study 3.

Statistics

The mean and the standard deviation or standard error of the mean were calculated for each variable. Intergroup differences were judged by one-way analysis of variance. Correlations were made using the Pearson test. Multivariate linear regression tests were used to define the best determinants of bone parameters. In study 3, to judge possible longitudinal differences in the groups (RF60, RF30, FF and C) following training, we used a two-way repeated measure analysis of variance (two-way-RM-Anova). The percentages of variations in physical qualities and bone parameters were calculated for the 4 groups. A value of p<0.05 was required in order to confirm the significance of the results.

Objective of the study

The main aim of the study was to compare the effects of two recreational football protocols (RF30: 2x30min vs RF60: 2x60min for 1 year) on bone health and physical performance parameters in a group of healthy inactive middle-aged men.

Materials and methods

Subjects

51 middle-aged men voluntarily participated in this study. Their mean age was 50.2 ± 4.5 years.

They were healthy and had no history of major orthopaedic problems or other disorders that affect bone metabolism.

Subjects were divided into two major categories: inactive (n=37) and active men (former football players; n=14).

Former football players were assigned into the formal football group (FF) based on their former and recent practice of football. They had been practicing football regularly in their adolescence and young adulthood ages (for at least 10 years) and were regular participants in national competitions. They had been training in their clubs 4 to 6 times per week, for 6-9 h/week for 10 years.

Inactive middle-aged men were randomly assigned into 3 groups: Recreational football 60 (RF60; n = 13), Recreational football 30 (RF30; n = 14) and control group (C; n = 10). Being inactive was defined as "performing less than 150 minutes of moderate intensity physical activity or 75 minutes of vigorous-intensity physical activity or an equivalent combination of moderate-and vigorous-intensity activity a week accumulated across work, home, transport or discretionary domains" (WHO, 2010). In addition, these participants didn't have a former regular practice of any impact sport in their adolescence and young adulthood ages.

A total of 41 subjects completed the study, and 10 subjects dropped out for different reasons.

Thus, 10 subjects from RF60, 10 subjects from RF30, 10 subjects from C and 11 subjects from FF completed the study.

Before the beginning of the intervention, the subjects who participated in the intervention group (RF60 and RF30) were checked by a specialised physician who gave them approval to perform physical activity at a high intensity.

Measurements

All measurements (anthropometric, body composition, bone and physical performance parameters) were performed in all 4 groups before and after the training period (duration: one year).

Recreational football protocol

The training lasted for 1 year with Several rules were used in the recreational football games to ensure better safety for the participants. Participants were not allowed to have major physical contact with each other; for example, while stealing the ball from the opponent player, it is legal in a normal game to use the body (shoulder) to steal the ball, but in our protocol, we directly stopped the game considering this as a foul to prevent risk of falls or any injuries related to physical contact.

Moreover, before each game, instructions were given to players such as, play for fun, try to win but not aggressively, play with no major physical contacts, play fairly and enjoy the game.

All participants performed a specific warm-up before starting the games. In all recreational football games, the two goal keepers were not from the study population and did not participate in the study.

Statistical analysis

The mean and the standard deviation or standard error of the mean were calculated for each variable. Intergroup differences were judged by one-way analysis of variance. Correlations between the percentage of variations of clinical, bone and physical parameters and the percentage of attendance were performed using the Pearson test. To judge possible longitudinal differences in the groups (RF60, RF30, FF and C) following training, we used a two-way repeated measure analysis of variance (two-way-RM-Anova). The percentages of variations in physical qualities and bone parameters were calculated for the 4 groups. A value of p<0.05 was required in order to confirm the significance of the results.

Results

Clinical characteristics and bone variables of the study population at baseline

Former football players were significantly taller than the control subjects. WB BMC and CSMI were significantly higher in FF compared to C. FN BMD, CSA, CSI and ISI were significantly higher in FF compared to C and RF30. Z was significantly higher in FF compared to C and RF60. In bold, significant difference; SD: standard deviation; BMI: body mass index; WB: whole body; BMC: bone mineral content; BMD: bone mineral density; L1-L4: Lumbar spine; TH: total hip; FN: femoral neck; CSA: cross sectional area; CSMI: cross-sectional moment of inertia; Z: section modulus; SI: strength index; BR: buckling ratio; CSI: compression strength index; BSI: bending strength index; ISI: impact strength index.

3.10

The effect of recreational football on physical performance parameters in the recreational football 30 group (RF30)

Concerning physical performance parameters, CMJ, 1RM half squat, absolute and relative VO2 max significantly increased. On the other hand, HG significantly decreased. In bold, significant differences; SD: standard deviation; CMJ: counter movement jump; HG: handgrip; RM: Repetition Maximum; VO2 max: maximum oxygen consumption.

3.11

The effect of recreational football on clinical and bone parameters in the Recreational Football 60 group (RF60)

After the 1-year intervention period, physical activity (min/week), WB BMC, L1-L4 BMD, TH BMD, FN BMD, CSMI, CSI, BSI and BSI significantly increased in RF60. On the other hand, WB BMD significantly decreased. In bold, significant difference; SD: standard deviation; BMI: body mass index; WB: whole body; BMC: bone mineral content; BMD: bone mineral density; L1-L4: Lumbar spine; TH: total hip; FN: femoral neck; CSA: cross sectional area; CSMI: cross-sectional moment of inertia; Z: section modulus; SI: strength index; BR: buckling ratio; CSI: compression strength index; BSI: bending strength index; ISI: impact strength index.

3.12 The effect of recreational football on physical performance parameters in the recreational football 60 group (RF60)

Absolute and relative VO2 max significantly increased but HG significantly decreased. In bold, significant differences; SD: standard deviation; CMJ: counter movement jump; HG: handgrip; RM: Repetition Maximum; VO2 max: maximum oxygen consumption.

3.13

The effect of recreational football on clinical and bone parameters in the recreational football groups (RF30+RF60 combined)

After the 1-year intervention period, physical activity (min/week), WB BMC, L1-L4 BMD, TH BMD, FN BMD, CSA, CSMI, Z, SI, CSI, BSI and BSI significantly increased. On the other hand, WB BMD significantly decreased. In bold, significant difference; SD: standard deviation; BMI: body mass index; WB: whole body; BMC: bone mineral content; BMD: bone mineral density; L1-L4: Lumbar spine; TH: total hip; FN: femoral neck; CSA: cross sectional area; CSMI: cross-sectional moment of inertia; Z: section modulus; SI: strength index; BR: buckling ratio; CSI: compression strength index; BSI: bending strength index; ISI: impact strength index.

3.14 The effect of recreational football on physical performance parameters in the recreational football groups (RF30+RF60 combined)

Concerning the physical parameters, CMJ, 1 RM half squat, 10 m sprint, absolute and relative VO2 max significantly increased but HG significantly decreased. In bold, significant differences; SD: standard deviation; CMJ: counter movement jump; HG: handgrip; RM: Repetition Maximum; VO2 max: maximum oxygen consumption.

Differences in the percentages of variation related to clinical and bone parameters among the groups

The percentage of variation in Physical activity (min/week) was significantly higher in RF60 and RF30 compared to C and F and in RF60 compared to RF30. FN BMD percentage of variation was significantly higher in the RF30 and RF60 compared to C and F. SI, CSI and ISI percentages of variation were significantly higher in RF30 compared to C. Concerning the physical performance parameters, the percentage of variation of the CMJ was significantly higher in RF30 compared to C. 1-RM bench press percentage of variation was significantly higher in RF60 and FF compared to C. In addition, absolute and relative VO2 max percentages of variation were significantly higher in RF30 and RF60 compared to FF and C. Significant difference in bold: F vs C a ; CF30 vs C b ; F vs CF30 c ; F vs RF60 d ; RF60 vs RF30 e ; RF60 vs C f ; RF30 vs FF g ; RF60 vs FF h ; SD: standard deviation; CMJ: counter movement jump; HG: handgrip; RM: Repetition Maximum; VO2 max: maximum oxygen consumption.

3.17 Differences in the percentages of variation related to clinical and bone parameters among the control, former football and the combination of the two recreational football groups Physical activity (min/week) and FN BMD percentages of variation were significantly higher in the RF (30+60) compared to C and FF. SI percentage of variation was significantly higher in RF (30+60) compared to C. CSI and ISI percentages of variation were significantly higher in RF (30+60) compared to C. 3.18 Differences in the percentages of variation related to physical performance parameters among control, formal football and the combination of the two recreational football groups

Concerning the physical performance parameters, the percentages of variations of the CMJ and the 1-RM half squat were significantly higher in RF (30+60) compared to C. 1-RM bench press percentage of variation was significantly higher in RF (60+30) and FF compared to C. In addition, absolute and relative VO2 max percentages of variations were significantly higher in RF (30 + 60) compared to FF and C. Concerning the physical performance parameters, the percentage of variation of the 1-RM bench press was significantly higher in RF60 compared to C. The percentages of variation of the CMJ and 10-m sprint were significantly higher in RF30 compared to C. Absolute and relative VO2 max percentages of variation were significantly higher in RF30 and RF60 compared to C. A group * time interaction was found in CMJ, 1-RM bench press and VO2 max (L/min and ml/min/kg). A group * time interaction was found in CMJ, 1-RM half squat, 10-m sprint, and VO2 max (L/min and ml/min/kg). The percentage of attendance to the training protocol was significantly higher in the recreational football 30 compared to the recreational football 60. On the other hand, subjects of the RF60 significantly played more hours compared to the RF30 groups.

Table 45: Differences in players' attendance to game between both recreational groups.

The significant differences are in bold.

Correlations between the percentage of variation of physical performance variables and the percentage of attendance of the recreational groups

There was no significant correlation found between the percentage of variation of physical performance variables and the percentage of attendance. The percentage of variation of the 10-m sprint performance was negatively correlated to FN BMD, CSMI and ISI. VO2 max (L/min) was negatively correlated to CSI and ISI. This study shows that 2x30 and 2x60 minutes per week of recreational football was capable of increasing FN BMD compared to controls. SI percentage of variation was significantly higher in RF30 compared to C. CSI and ISI percentages of variation were significantly higher in RF30 and RF60 compared to C. BSI percentage of variation was significantly higher in RF30 compared to C. The results of this analysis are in line with those of our previous analysis in which we used a 2-way-RM-Anova.

Concerning the physical performance parameters, the percentages of variation of the CMJ and 10-m sprint were significantly higher in RF30 compared to C. Absolute and relative VO2 max percentages of variation were significantly higher in RF30 and RF60 compared to C. overall, there were no significant differences between both experimental groups (RF60 and RF30) concerning the percentages of variations in bone health parameters and in physical performance variables. Hence, most of the health benefits can occur in response to 2*30 minutes of recreational football per week. It is interesting to mention that adherence was significantly higher in RF30 compared to RF60.

Within group differences

After the 1-year intervention period, we did not find any significant change in clinical and bone parameters in the control group except for a decrease in the whole body bone mineral density.

Bone loss with ageing is normal in this age group. The decrease was only observed at the whole body BMD. Concerning physical performance variables, we only find a significant decrease in handgrip strength. No significant changes were found in the other physical parameters.

Concerning the RF30 group, WB BMC, FN BMD, CSA, CSMI, Z, SI, CSI, BSI and ISI significantly increased after the 1-year intervention period. This is the first study that shows that a low volume of recreational football (2x30 min/week) is effective in improving several bone parameters in middle-aged men. A significant increase was found in the FN BMD but not in the L1-L4 BMD. This could be explained by the fact that the cortical component of the femoral neck is more influenced by mechanical factors than the trabecular component of the lumbar spine; the latter is much more affected by genetic factors [START_REF] Eisman | Genetics of osteoporosis[END_REF]. Moreover, the low volume of training (2x30 min/week) could also be the reason for not finding a significant change in L1-L4 BMD.

On the other hand, WB BMC, L1-L4 BMD, TH BMD, FN BMD, CSMI, CSI, BSI and ISI significantly increased in RF60 group after a 1-year intervention period. These improvements are seen in weight bearing sites which is logical because soccer is a weight-bearing high impact sport. These results support the principle of specificity of bone adaptation to exercise [START_REF] Kohrt | Physical Activity and Bone Health[END_REF]. These results are with accordance with many studies that investigated the effect of football on bone health [START_REF] Zouch | Young male soccer players exhibit additional bone mineral acquisition during the peripubertal period: 1-year longitudinal study[END_REF]Skoradal et al., 2018;[START_REF] Ferry Béatrice | Bone health during late adolescence: effects of an 8-month training program on bone geometry in female athletes[END_REF].

L1-L4 BMD and TH BMD were significantly increased only in RF60 but not in RF30. This may be related to the fact that the subjects of the RF60 group performed a higher volume of training. It is recognised that bone adapts to the mechanical stress that is applied to it. Higher training volumes are associated with higher mechanical stress that may lead to higher bone adaptations that are shown in RF60.

Concerning physical performance parameters, CMJ, 1RM half-squat, absolute and relative VO2 max significantly increased in RF30. On the other hand, only the absolute and relative VO2 max significantly increased in RF60. The adherence to the training was higher in RF30 compared to RF60. In addition, training intensity might be higher in the RF30 compared to the RF60; this might explain the absence of improvement in the strength parameters in the RF60 group. Finally, fatigue caused by the higher volume in the RF60 group might explain the absence of improvement in the strength parameters.

HG significantly decreased in both groups (RF30 and RF60). This result is not surprising since the training protocol targeted the lower limbs.

1.2 Analysis conducted on 4 groups (RF60, RF30, FF and C)

Between group differences

Concerning the former football group, we did not find any significant changes concerning the clinical and bone parameters except a decrease in the whole body bone mineral density after a 1-year period. Also, no significant changes were found concerning the physical performance parameters. The participants of this group are players that played football for many consecutive years. Osteogenic response only takes place when the load exerted on the bone exceeds the habitual load that is imposed on it. A gradual increase in load or an overload is required to achieve this response. In the FF group, there were no changes in intensity or volume of the training for many years. The players of the FF group might be adapted to the type of stimulus elicited by the football games. This adaptation may explain the fact that there are no significant changes in bone and physical parameters after this one-year intervention.

Furthermore, these former players had higher baseline BMD compared to controls, so the benefits associated with physical training will be low. The higher a subject's baseline BMD is, the lower the benefits associated with physical training will be low. Baseline BMD is negatively correlated to the increase of BMD in response to exercise [START_REF] Kohrt | Physical Activity and Bone Health[END_REF].

Moreover, according to [START_REF] Burr | Effects of biomechanical stress on bones in animals[END_REF], bone tissue quickly gets used to the type and intensity of exercise. The variation is very important to avoid reaching a plateau. In practice, in order to avoid a stagnation of the bone response, it is necessary to change the type and intensity of exercise and increase the level of mechanical stress in the workouts performed.

Finally, osteogenic response to exercise is stronger in adolescents compared to middle-aged men [START_REF] Santos | Exercise and bone health across the lifespan[END_REF].

Limitations

First, the cross-sectional nature of the first two studies is a limit because it does not allow us to assert a causal relationship between the anthropometric and physical performance

CONCLUSIONS AND PERSPECTIVES

This PhD thesis conducted on a group of middle-aged men mainly shows that:

• First, lean mass was the strongest determinant of WB BMC, VO2 max (L/min) was the strongest determinant of WB BMD, TH BMD and FN BMD while maximum power of the lower limbs was the strongest determinant of total radius BMD. Accordingly, VO2 max (L/min), lean mass and maximum power of the lower limbs are the strongest determinants of bone variables in middle-aged men.

• Second, former football practice is associated with higher composite indices of femoral neck strength (CSI, BSI and ISI) in middle-aged men. Hence, regular football practice before the young adulthood period may confer residual benefits in composite indices of femoral neck strength in middle-aged men.

• Last, we compared the effects of two recreational football protocols (RF30: 2x30min vs RF60: 2x60min for 1 year) on bone health and physical performance parameters in a group of healthy middle-aged men. We found that after the 1-year intervention period, WB BMC, FN BMD, CSMI, CSI, BSI and ISI significantly increased in both experimental groups but not in the control group nor in the former football group.

Moreover, absolute and relative VO2 max significantly increased in both experimental groups but not in the control group nor in the former football group. We noticed group * time interactions in FN BMD, CMJ and VO2 max (L/mn and ml/mn/kg). The percentages of variations in bone health parameters and in physical performance variables were not significantly different in both experimental groups.

In view of our results and limitations, it would be interesting in the future to conduct several studies. First, it would be interesting to conduct a similar longitudinal study with higher numbers of participants and a longer duration of training, adding several questionnaires related to bone loading score, sleep quality, quality of life, protein intake and calcium consumption, and blood tests for the evaluation of lipid profile, glucose regulation and inflammatory cytokines.

Second, it would be useful to study the effects of the cessation of training (detraining) on these parameters in the same population.

Third, investigating the effects of recreational football on bone health parameters in agematched females would be clinically relevant. Such studies can allow us to investigate the sex-difference osteogenic response to football in this age group.

Fourth, it would be also interesting to investigate the effects of the practice of other team sports (handball, basketball and volleyball) on clinical, bone and physical performance variables in the same age population.

Fifth, it would be clinically pertinent to explore the effectiveness of soccer practice (walking football) on body composition, functional strength, bone health parameters and quality of life in elderly subjects with sarcopenia.

Finally, since metabolic syndrome is becoming very common in young adults whose ages are below 40 years, it would be judicious to explore the effects of soccer practice on body composition, blood glucose, blood lipid profile, blood pressure and physical performance variables in young adults (30-39 years old) with metabolic syndrome.

SUMMARY OF THE THESIS IN FRENCH/ RÉSUMÉ DE LA THÈSE EN FRANÇAIS I-Introduction et revue de littérature :

L'ostéoporose se caractérise par une faible densité minérale osseuse (DMO) et une détérioration de la microarchitecture osseuse conduisant à un risque accru de fracture (OMS, 1994).

L'ostéoporose est traditionnellement considérée comme un problème de santé pour les femmes mais c'est un problème de santé pour les hommes aussi [START_REF] Riggs | A population-based assessment of rates of bone loss at multiple skeletal sites: evidence for substantial trabecular bone loss in young adult women and men[END_REF]) et est souvent ignorée [START_REF] Madeo | The osteoporotic male: Overlooked and undermanaged?[END_REF]. De plus, c'est la maladie osseuse la plus courante chez l'être humain, représentant un problème majeur de santé publique (Tümay et al. 2017). Environ 9 millions de fractures chaque année sont liées à l'ostéoporose (1 fracture ostéoporotique a lieu toutes les 3 secondes) (Johnel et [START_REF] Johnell | An estimate of the worldwide prevalence and disability associated with osteoporotic fractures[END_REF]. Une femme sur 3 et 1 homme sur 5 âgés de plus de 50 ans rencontreront des fractures liées à l'ostéoporose au cours de leur vie [START_REF] Melton | Bone density and fracture risk in men[END_REF][START_REF] Melton | Perspective. How many women have osteoporosis?[END_REF]. Les fractures de la hanche sont considérées comme les plus graves de ces fractures car elles sont corrélées à un taux élevé de morbidité et de mortalité et surtout chez les hommes [START_REF] Zaheer | Osteoporosis: Prevention and Treatment[END_REF]. En 2001, un groupe d'experts a défini l'ostéoporose comme « un trouble du squelette caractérisé par une faible résistance osseuse qui augmente le risque de fractures » (NIH, 2001). La résistance osseuse est influencée par trois facteurs majeurs qui sont la DMO, la répartition géométrique de la masse osseuse et les propriétés des matériaux [START_REF] Cole | Whole Bone Mechanics and Bone Quality[END_REF]. La DMO mesurée par DXA est un déterminant important de résistance osseuse à tout âge [START_REF] Goulding | Overweight and obese children have low bone mass and area for their weight[END_REF]. La DMO est fortement corrélée à la résistance osseuse et peut définir environ 70% de sa variabilité. La DMO reste le meilleur déterminant de la résistance mécanique osseuse [START_REF] Bouxsein | Determinants of skeletal fragility[END_REF]. La géométrie osseuse affecte également la résistance osseuse. Des sujets ayant la même DMO peuvent présenter différents niveaux de résistance osseuse en fonction de leurs dimensions osseuses et de leur géométrie osseuse [START_REF] Bouxsein | Determinants of skeletal fragility[END_REF]. De plus, la microarchitecture osseuse influence également la résistance osseuse (Dalle [START_REF] Carbonare | Bone microarchitecture as an important determinant of bone strength[END_REF]. Des sujets ayant une DMO normale mais une microarchitecture détériorée (mauvaises propriétés des matériaux), peuvent être sujets aux fractures (Dalle [START_REF] Carbonare | Bone microarchitecture as an important determinant of bone strength[END_REF]. En plus de la DMO, d'autres variables densitométriques prédisent également les fractures ostéoporotiques telles que les indices de résistance du col fémoral et les indices géométriques du col fémoral de Beck. Les indices de résistance du col fémoral peuvent être bénéfiques dans la prédiction du risque fracturaire au niveau de la hanche. Ces indices reflètent la capacité du col fémoral à résister à un impact en flexion ou en compression axiale et à absorber l'énergie [START_REF] Karlamangla | Hip fracture risk assessment using composite indices of femoral neck strength: the Rancho Bernardo study[END_REF]). Les indices géométriques du col fémoral sont des déterminants positifs de la résistance mécanique et sont utilisés dans la prédiction du risque de fracture (Kaptoge, 2008 ;Beck, 2009).

L'ostéoporose peut être classée en ostéoporose primaire et ostéoporose secondaire. Il y a deux types d'ostéoporose primaire : type 1 et type 2 [START_REF] Dobbs | Osteoporosis[END_REF]. L'ostéoporose de type 1 est appelée ostéoporose post-ménopausique car elle apparaît généralement chez les femmes à un âge pas si longtemps après la ménopause [START_REF] Gallagher | Prevention and treatment of postmenopausal osteoporosis[END_REF]. De plus, elle peut être trouvée chez les hommes à âge moyen. L'ostéoporose de type 2 ou ostéoporose sénile est liée au vieillissement. Avec le vieillissement, l'équilibre entre la formation et la résorption de l'os est déplacé favorisant une plus grande résorption osseuse et une moindre formation osseuse [START_REF] Demontiero | Aging and bone loss: new insights for the clinician[END_REF]. L'ostéoporose secondaire est liée à des facteurs tels que des troubles médicaux ou l'utilisation d'un certain type de médicaments [START_REF] Dobbs | Osteoporosis[END_REF].

La détérioration osseuse liée au vieillissement est accélérée par la présence de plusieurs facteurs de risque [START_REF] Pouresmaeili | A comprehensive overview on osteoporosis and its risk factors[END_REF]. Afin de réduire le risque de fractures, il est important de réduire les facteurs de risque d'ostéoporose (tabagisme, mode de vie sédentaire, absence d'activité physique, alcoolisme, perte de poids, prise de certains médicaments) tout au long de la vie et d'augmenter le pic de masse osseuse. Le pic de masse osseuse (PMO) est «la quantité du tissu osseux présent à la fin de la maturation squelettique » [START_REF] Bonjour | Peak bone mass[END_REF]. Après

avoir atteint la PMO, la perte osseuse avec le vieillissement est universelle chez les deux sexes et se produira. L'augmentation du PMO pendant la croissance est une stratégie importante pour prévenir les futurs cas d'ostéoporose. L'augmentation des niveaux d'activité physique à n'importe quelle période de vie réduit le risque de perte osseuse et de fractures ostéoporotiques [START_REF] Carter | Physical Activity and Bone Health[END_REF]. L'os s'adapte à la contrainte mécanique qui lui est appliquée.

L'exercice physique soumet l'os à une contrainte mécanique supérieure à la charge habituelle exercée par la contraction musculaire et la charge gravitationnelle (contact entre un objet pondéré (corps humain) et un autre objet ou substrat (sol) (Judex et Carlsonl, 2009).

L'activité physique pourrait être bénéfique pour augmenter la masse osseuse et éviter sa perte mais le choix de l'activité physique est très important, parce que certains types d'activités physiques (à fort impact : course à pied, football, gymnastique et volleyball) sont supérieurs aux autres (natation et cyclisme) pour affecter la santé osseuse [START_REF] Kohrt | Physical Activity and Bone Health[END_REF]. Par

Régressions linéaires multiples

La masse maigre était le déterminant le plus fort du CMO CE et du CSMI. La VO2 max (L/min) était le déterminant le plus fort de la DMO CE, la DMO HE, la DMO CF et la CSA. La puissance maximale était le déterminant le plus fort de la DMO radius.

Conclusion :

La VO2 max (L / min), la masse maigre et la puissance maximale des membres inférieurs (watts) sont les déterminants les plus puissants des paramètres osseux chez les hommes d'âge moyen.

Nos résultats peuvent être utiles pour construire de nouveaux programmes d'exercices pour la prévention et la détection précoce de l'ostéoporose et/ou de l'ostéopénie chez les hommes. Par conséquent, un entraînement aérobie à haute intensité peut améliorer la santé des os et les paramètres physiques chez les hommes (par exemple : Football).

Étude 2 :

Indices de résistance osseuse du col fémoral chez des sujets inactifs d'âge moyen par rapport aux anciens joueurs de football.

Objectif :

Comparer les indices de résistance osseuse du col fémoral chez un groupe d'hommes cinquantenaires inactifs et des anciens joueurs de football de même âge.

Corrélations entre les variables de performance physique et les caractéristiques osseuses de la population étudiée

Le saut vertical, le saut horizontal (HJ), 1-RM squat, 10-m sprint et la VO2 max (ml/min/kg) étaient significativement corrélées aux indices de résistance osseuse du col fémoral.

Variables osseuses ajustées pour plusieurs covariants dans les 2 groupes

Après ajustement pour la VO2 max (ml/min /kg) et la performance au sprint : la majorité des paramètres osseux est restée significativement plus élevée chez les anciens joueurs de football que chez les hommes inactifs. Après ajustement pour l'activité physique (min/semaine) et le pourcentage de graisse corporelle, la majorité des paramètres osseux est restée significativement plus élevée chez les anciens joueurs de football que chez les hommes inactifs.

Conclusion

La pratique antérieure du football à l'adolescence est associée à une augmentation des indices de résistance osseuse du col fémoral chez les hommes d'âge moyen. La pratique du football à l'adolescence semble avoir un effet anti-fracturaire plus tard dans la vie. Par conséquent, l'élaboration des programmes d'exercices pendant l'adolescence doit être adaptée.

Étude 3 :

Les effets d'un protocole de football récréatif d'un an sur la densité minérale osseuse et les paramètres de performance physique dans un groupe d'hommes sains et inactifs de 50 ans.

Objectif

Comparer les effets de deux protocoles de football récréatif (RF30 : 2x30min vs RF60 :

2x60min pendant 1 an) sur la santé osseuse et les paramètres de performance physique dans un groupe d'hommes d'âge moyen inactifs en bonne santé. Une interaction groupe * temps a été trouvée pour la DMO CF et l'AP.

Interactions groupe* temps concernant les paramètres physiques dans les 4 groupes

Une interaction groupe * temps a été trouvée pour la DV, 1-RM bench press et VO2 max (L/min and ml/min/kg).

Pourcentages de variations des paramètres cliniques et osseux dans les 4 groupes

Le pourcentage de variation de l'activité physique (min/semaine) était significativement plus

Figure 1 :

 1 Figure 1: Microscopic view of normal (a) and osteoporotic bone (b) (van Oostwaard, 2018). .................................................................................................................................................. Figure 2: Schematic representation of DXA scan's X-rays source and detector system (Pisani et al., 2013)...............................................................................................................................Figure 3: a: Cortical and b: trabecular bone loss changes in both sexes (Seeman, 2002). .....Figure 4: Distribution of osteoporosis cases in major European countries (2010) (Hernlund et al., 2013). .................................................................................................................................Figure 5: Representation of the age-adjusted indices rates in women in several countries in the world (Sibai et al. 2011).....................................................................................................Figure 6: Representation of the age-adjusted indices rates in men in several countries in the world (Sibai et al. 2011)...........................................................................................................Figure 7: Causes of bone fractures..........................................................................................Figure 8: Characteristics of bones to resist to applied loads...................................................Figure 9: The effect of an increase in cortex diameter on bone compression and bending strength with no change in areal density (Bouxsein, 2005). ....................................................Figure 10: Effect of trabecular microarchitecture on buckling strength. ................................Figure 11: Influence of PBM on the onset of osteoporosis later in life (Rizzoli et al. 2010).Figure 12: Bone mineral content gain in relation to age and sex (Bailey et al., 1999)...........Figure 13: Determinant of peak bone mass (Bonjour et al. 2009)..........................................

Figure 2 :

 2 Figure 1: Microscopic view of normal (a) and osteoporotic bone (b) (van Oostwaard, 2018). .................................................................................................................................................. Figure 2: Schematic representation of DXA scan's X-rays source and detector system (Pisani et al., 2013)...............................................................................................................................Figure 3: a: Cortical and b: trabecular bone loss changes in both sexes (Seeman, 2002). .....Figure 4: Distribution of osteoporosis cases in major European countries (2010) (Hernlund et al., 2013). .................................................................................................................................Figure 5: Representation of the age-adjusted indices rates in women in several countries in the world (Sibai et al. 2011).....................................................................................................Figure 6: Representation of the age-adjusted indices rates in men in several countries in the world (Sibai et al. 2011)...........................................................................................................Figure 7: Causes of bone fractures..........................................................................................Figure 8: Characteristics of bones to resist to applied loads...................................................Figure 9: The effect of an increase in cortex diameter on bone compression and bending strength with no change in areal density (Bouxsein, 2005). ....................................................Figure 10: Effect of trabecular microarchitecture on buckling strength. ................................Figure 11: Influence of PBM on the onset of osteoporosis later in life (Rizzoli et al. 2010).Figure 12: Bone mineral content gain in relation to age and sex (Bailey et al., 1999)...........Figure 13: Determinant of peak bone mass (Bonjour et al. 2009)..........................................

Figure 3 :

 3 Figure 1: Microscopic view of normal (a) and osteoporotic bone (b) (van Oostwaard, 2018). .................................................................................................................................................. Figure 2: Schematic representation of DXA scan's X-rays source and detector system (Pisani et al., 2013)...............................................................................................................................Figure 3: a: Cortical and b: trabecular bone loss changes in both sexes (Seeman, 2002). .....Figure 4: Distribution of osteoporosis cases in major European countries (2010) (Hernlund et al., 2013). .................................................................................................................................Figure 5: Representation of the age-adjusted indices rates in women in several countries in the world (Sibai et al. 2011).....................................................................................................Figure 6: Representation of the age-adjusted indices rates in men in several countries in the world (Sibai et al. 2011)...........................................................................................................Figure 7: Causes of bone fractures..........................................................................................Figure 8: Characteristics of bones to resist to applied loads...................................................Figure 9: The effect of an increase in cortex diameter on bone compression and bending strength with no change in areal density (Bouxsein, 2005). ....................................................Figure 10: Effect of trabecular microarchitecture on buckling strength. ................................Figure 11: Influence of PBM on the onset of osteoporosis later in life (Rizzoli et al. 2010).Figure 12: Bone mineral content gain in relation to age and sex (Bailey et al., 1999)...........Figure 13: Determinant of peak bone mass (Bonjour et al. 2009)..........................................

  Figure 1: Microscopic view of normal (a) and osteoporotic bone (b) (van Oostwaard, 2018). .................................................................................................................................................. Figure 2: Schematic representation of DXA scan's X-rays source and detector system (Pisani et al., 2013)...............................................................................................................................Figure 3: a: Cortical and b: trabecular bone loss changes in both sexes (Seeman, 2002). .....Figure 4: Distribution of osteoporosis cases in major European countries (2010) (Hernlund et al., 2013). .................................................................................................................................Figure 5: Representation of the age-adjusted indices rates in women in several countries in the world (Sibai et al. 2011).....................................................................................................Figure 6: Representation of the age-adjusted indices rates in men in several countries in the world (Sibai et al. 2011)...........................................................................................................Figure 7: Causes of bone fractures..........................................................................................Figure 8: Characteristics of bones to resist to applied loads...................................................Figure 9: The effect of an increase in cortex diameter on bone compression and bending strength with no change in areal density (Bouxsein, 2005). ....................................................Figure 10: Effect of trabecular microarchitecture on buckling strength. ................................Figure 11: Influence of PBM on the onset of osteoporosis later in life (Rizzoli et al. 2010).Figure 12: Bone mineral content gain in relation to age and sex (Bailey et al., 1999)...........Figure 13: Determinant of peak bone mass (Bonjour et al. 2009)..........................................

Figure 5 :

 5 Figure 1: Microscopic view of normal (a) and osteoporotic bone (b) (van Oostwaard, 2018). .................................................................................................................................................. Figure 2: Schematic representation of DXA scan's X-rays source and detector system (Pisani et al., 2013)...............................................................................................................................Figure 3: a: Cortical and b: trabecular bone loss changes in both sexes (Seeman, 2002). .....Figure 4: Distribution of osteoporosis cases in major European countries (2010) (Hernlund et al., 2013). .................................................................................................................................Figure 5: Representation of the age-adjusted indices rates in women in several countries in the world (Sibai et al. 2011).....................................................................................................Figure 6: Representation of the age-adjusted indices rates in men in several countries in the world (Sibai et al. 2011)...........................................................................................................Figure 7: Causes of bone fractures..........................................................................................Figure 8: Characteristics of bones to resist to applied loads...................................................Figure 9: The effect of an increase in cortex diameter on bone compression and bending strength with no change in areal density (Bouxsein, 2005). ....................................................Figure 10: Effect of trabecular microarchitecture on buckling strength. ................................Figure 11: Influence of PBM on the onset of osteoporosis later in life (Rizzoli et al. 2010).Figure 12: Bone mineral content gain in relation to age and sex (Bailey et al., 1999)...........Figure 13: Determinant of peak bone mass (Bonjour et al. 2009)..........................................

Figure 6 :

 6 Figure 1: Microscopic view of normal (a) and osteoporotic bone (b) (van Oostwaard, 2018). .................................................................................................................................................. Figure 2: Schematic representation of DXA scan's X-rays source and detector system (Pisani et al., 2013)...............................................................................................................................Figure 3: a: Cortical and b: trabecular bone loss changes in both sexes (Seeman, 2002). .....Figure 4: Distribution of osteoporosis cases in major European countries (2010) (Hernlund et al., 2013). .................................................................................................................................Figure 5: Representation of the age-adjusted indices rates in women in several countries in the world (Sibai et al. 2011).....................................................................................................Figure 6: Representation of the age-adjusted indices rates in men in several countries in the world (Sibai et al. 2011)...........................................................................................................Figure 7: Causes of bone fractures..........................................................................................Figure 8: Characteristics of bones to resist to applied loads...................................................Figure 9: The effect of an increase in cortex diameter on bone compression and bending strength with no change in areal density (Bouxsein, 2005). ....................................................Figure 10: Effect of trabecular microarchitecture on buckling strength. ................................Figure 11: Influence of PBM on the onset of osteoporosis later in life (Rizzoli et al. 2010).Figure 12: Bone mineral content gain in relation to age and sex (Bailey et al., 1999)...........Figure 13: Determinant of peak bone mass (Bonjour et al. 2009)..........................................

Figure 7 :

 7 Figure 1: Microscopic view of normal (a) and osteoporotic bone (b) (van Oostwaard, 2018). .................................................................................................................................................. Figure 2: Schematic representation of DXA scan's X-rays source and detector system (Pisani et al., 2013)...............................................................................................................................Figure 3: a: Cortical and b: trabecular bone loss changes in both sexes (Seeman, 2002). .....Figure 4: Distribution of osteoporosis cases in major European countries (2010) (Hernlund et al., 2013). .................................................................................................................................Figure 5: Representation of the age-adjusted indices rates in women in several countries in the world (Sibai et al. 2011).....................................................................................................Figure 6: Representation of the age-adjusted indices rates in men in several countries in the world (Sibai et al. 2011)...........................................................................................................Figure 7: Causes of bone fractures..........................................................................................Figure 8: Characteristics of bones to resist to applied loads...................................................Figure 9: The effect of an increase in cortex diameter on bone compression and bending strength with no change in areal density (Bouxsein, 2005). ....................................................Figure 10: Effect of trabecular microarchitecture on buckling strength. ................................Figure 11: Influence of PBM on the onset of osteoporosis later in life (Rizzoli et al. 2010).Figure 12: Bone mineral content gain in relation to age and sex (Bailey et al., 1999)...........Figure 13: Determinant of peak bone mass (Bonjour et al. 2009)..........................................

Figure 8 :

 8 Figure 1: Microscopic view of normal (a) and osteoporotic bone (b) (van Oostwaard, 2018). .................................................................................................................................................. Figure 2: Schematic representation of DXA scan's X-rays source and detector system (Pisani et al., 2013)...............................................................................................................................Figure 3: a: Cortical and b: trabecular bone loss changes in both sexes (Seeman, 2002). .....Figure 4: Distribution of osteoporosis cases in major European countries (2010) (Hernlund et al., 2013). .................................................................................................................................Figure 5: Representation of the age-adjusted indices rates in women in several countries in the world (Sibai et al. 2011).....................................................................................................Figure 6: Representation of the age-adjusted indices rates in men in several countries in the world (Sibai et al. 2011)...........................................................................................................Figure 7: Causes of bone fractures..........................................................................................Figure 8: Characteristics of bones to resist to applied loads...................................................Figure 9: The effect of an increase in cortex diameter on bone compression and bending strength with no change in areal density (Bouxsein, 2005). ....................................................Figure 10: Effect of trabecular microarchitecture on buckling strength. ................................Figure 11: Influence of PBM on the onset of osteoporosis later in life (Rizzoli et al. 2010).Figure 12: Bone mineral content gain in relation to age and sex (Bailey et al., 1999)...........Figure 13: Determinant of peak bone mass (Bonjour et al. 2009)..........................................

  Figure 1: Microscopic view of normal (a) and osteoporotic bone (b) (van Oostwaard, 2018). .................................................................................................................................................. Figure 2: Schematic representation of DXA scan's X-rays source and detector system (Pisani et al., 2013)...............................................................................................................................Figure 3: a: Cortical and b: trabecular bone loss changes in both sexes (Seeman, 2002). .....Figure 4: Distribution of osteoporosis cases in major European countries (2010) (Hernlund et al., 2013). .................................................................................................................................Figure 5: Representation of the age-adjusted indices rates in women in several countries in the world (Sibai et al. 2011).....................................................................................................Figure 6: Representation of the age-adjusted indices rates in men in several countries in the world (Sibai et al. 2011)...........................................................................................................Figure 7: Causes of bone fractures..........................................................................................Figure 8: Characteristics of bones to resist to applied loads...................................................Figure 9: The effect of an increase in cortex diameter on bone compression and bending strength with no change in areal density (Bouxsein, 2005). ....................................................Figure 10: Effect of trabecular microarchitecture on buckling strength. ................................Figure 11: Influence of PBM on the onset of osteoporosis later in life (Rizzoli et al. 2010).Figure 12: Bone mineral content gain in relation to age and sex (Bailey et al., 1999)...........Figure 13: Determinant of peak bone mass (Bonjour et al. 2009)..........................................

Figure 10 :

 10 Figure 1: Microscopic view of normal (a) and osteoporotic bone (b) (van Oostwaard, 2018). .................................................................................................................................................. Figure 2: Schematic representation of DXA scan's X-rays source and detector system (Pisani et al., 2013)...............................................................................................................................Figure 3: a: Cortical and b: trabecular bone loss changes in both sexes (Seeman, 2002). .....Figure 4: Distribution of osteoporosis cases in major European countries (2010) (Hernlund et al., 2013). .................................................................................................................................Figure 5: Representation of the age-adjusted indices rates in women in several countries in the world (Sibai et al. 2011).....................................................................................................Figure 6: Representation of the age-adjusted indices rates in men in several countries in the world (Sibai et al. 2011)...........................................................................................................Figure 7: Causes of bone fractures..........................................................................................Figure 8: Characteristics of bones to resist to applied loads...................................................Figure 9: The effect of an increase in cortex diameter on bone compression and bending strength with no change in areal density (Bouxsein, 2005). ....................................................Figure 10: Effect of trabecular microarchitecture on buckling strength. ................................Figure 11: Influence of PBM on the onset of osteoporosis later in life (Rizzoli et al. 2010).Figure 12: Bone mineral content gain in relation to age and sex (Bailey et al., 1999)...........Figure 13: Determinant of peak bone mass (Bonjour et al. 2009)..........................................

Figure 11 :

 11 Figure 1: Microscopic view of normal (a) and osteoporotic bone (b) (van Oostwaard, 2018). .................................................................................................................................................. Figure 2: Schematic representation of DXA scan's X-rays source and detector system (Pisani et al., 2013)...............................................................................................................................Figure 3: a: Cortical and b: trabecular bone loss changes in both sexes (Seeman, 2002). .....Figure 4: Distribution of osteoporosis cases in major European countries (2010) (Hernlund et al., 2013). .................................................................................................................................Figure 5: Representation of the age-adjusted indices rates in women in several countries in the world (Sibai et al. 2011).....................................................................................................Figure 6: Representation of the age-adjusted indices rates in men in several countries in the world (Sibai et al. 2011)...........................................................................................................Figure 7: Causes of bone fractures..........................................................................................Figure 8: Characteristics of bones to resist to applied loads...................................................Figure 9: The effect of an increase in cortex diameter on bone compression and bending strength with no change in areal density (Bouxsein, 2005). ....................................................Figure 10: Effect of trabecular microarchitecture on buckling strength. ................................Figure 11: Influence of PBM on the onset of osteoporosis later in life (Rizzoli et al. 2010).Figure 12: Bone mineral content gain in relation to age and sex (Bailey et al., 1999)...........Figure 13: Determinant of peak bone mass (Bonjour et al. 2009)..........................................

Figure 13 :

 13 Figure 1: Microscopic view of normal (a) and osteoporotic bone (b) (van Oostwaard, 2018). .................................................................................................................................................. Figure 2: Schematic representation of DXA scan's X-rays source and detector system (Pisani et al., 2013)...............................................................................................................................Figure 3: a: Cortical and b: trabecular bone loss changes in both sexes (Seeman, 2002). .....Figure 4: Distribution of osteoporosis cases in major European countries (2010) (Hernlund et al., 2013). .................................................................................................................................Figure 5: Representation of the age-adjusted indices rates in women in several countries in the world (Sibai et al. 2011).....................................................................................................Figure 6: Representation of the age-adjusted indices rates in men in several countries in the world (Sibai et al. 2011)...........................................................................................................Figure 7: Causes of bone fractures..........................................................................................Figure 8: Characteristics of bones to resist to applied loads...................................................Figure 9: The effect of an increase in cortex diameter on bone compression and bending strength with no change in areal density (Bouxsein, 2005). ....................................................Figure 10: Effect of trabecular microarchitecture on buckling strength. ................................Figure 11: Influence of PBM on the onset of osteoporosis later in life (Rizzoli et al. 2010).Figure 12: Bone mineral content gain in relation to age and sex (Bailey et al., 1999)...........Figure 13: Determinant of peak bone mass (Bonjour et al. 2009)..........................................

8 : 9 :

 89 Examples of secondary osteoporosis. .......................................................................Table 7 :The prevalence distribution of osteoporosis in 27 European contries. ..................... Table Total numbers of osteoporosis related deaths in 27 European countries.................. Table Summary of longitudinal studies regarding the effects of soccer on bone in boys aged between 8 to 16 years. ..................................................................................................... Table 10: Summary of longitudinal studies regarding the effects of soccer on bone in men aged between 20 and 54 years.................................................................................................. Table 11: Summary of longitudinal studies regarding the effects of soccer on bone parameters in elderly male (aged 60+ years). .......................................................................... Table 12: Summary of longitudinal studies investigating the effect of soccer practice on bone in female aged between 30 and 61 years.................................................................................. Table 13: Summaryof cross sectional studies related to young female soccer and aged matched inactive controls aged between 15 to 27 years. ......................................................... Table 14: Summary of cross sectional studies related to young male soccer and aged matched inactive controls aged between 18 and 30 years. ..................................................................... Table 15: Summary of cross sectional studies related to male soccer players and aged matched inactive controls aged between 10 to 15 years. ......................................................... Table 16: Summary of cross sectional studies related to female soccer players and aged matched inactive controls aged between 10 to 18 years. ......................................................... Table 17: Summary of cross-sectional studies related to male soccer players and aged matched inactive controls aged between 50 years and older. .................................................. Table 18: Design of the three studies. .................................................................................... Table

  at baseline. ............................................... Table 22: Physical performance variables of the study population before the intervention. Table 23: Clinical and bone parameters before and after the training period in the control group. ..................................................................................................................................... Table 24: Physical performance variables at baseline and after the 1-year period in the control group. ......................................................................................................................... Table 25: Clinical and bone parameters before and after the training period in the former football group. ........................................................................................................................ Table 26: Physical performance parameters before and after the training period in the former football group. ........................................................................................................................ Table 27: Clinical and bone parameters before and after the training period in the recreational football 30 group. ............................................................................................... Table 28: Physical performance parameters before and after the training period in the recreational football 30 group. ...............................................................................................

Table 29 :

 29 Clinical and bone parameters before and after the training period in the recreational football 60 group. ...............................................................................................Table 30: Physical performance parameters before and after the training period in the recreational football 60 group. ............................................................................................... Table 31: Clinical and bone parameters before and after the training period in the recreational football group (RF30+ RF60)............................................................................ Table 32: Physical performance parameters before and after the training period in the recreational football 30 and 60 combined group. .................................................................. Table 33: Differences in the percentages of variation of the clinical and bone variables among control, former football and recreational football 30 and recreational football 60 groups..................................................................................................................................... Table 34: Differences in the percentages of variation of the clinical and bone variables among control, former football and recreational football 30 and recreational football 60 groups..................................................................................................................................... Table 35: Differences among control, former football and recreational football groups combined in the percentages of variation of clinical and bone variables. ............................. Table 36: Differences in the percentages of variation related to physical performance parameters among control, formal football and the combination of the two recreational football groups. ...................................................................................................................... Table

  A two-way repeated measures ANOVA of the clinical and bone parameters among all 4 groups............................................................................................................................. Table 40: A two-way repeated measure ANOVA of the physical performance variables among all 4 groups. ................................................................................................................ Table 41: A two-way repeated measure ANOVA of the clinical and bone parameters among the former football, control and the combination of the recreational football groups. .......... Table 42: A two-way repeated measure ANOVA of the physical performance variables among the former football, control and the combination of the recreational football groups. ................................................................................................................................................ Table 43: A two-way repeated measure ANOVA of the clinical and bone parameters among the control, recreational 60 and recreational 30 groups. ........................................................ Table 44: A two-way repeated measure ANOVA of the physical performance variables among the control, recreational 60 and recreational 30 groups. ............................................ Table

Figure 1 :

 1 Figure 1: Microscopic view of normal (a) and osteoporotic bone (b) (van Oostwaard, 2018).

  AbbreviationCalculation formulas

Figure 3 :

 3 Figure 3: a: Cortical and b: trabecular bone loss changes in both sexes[START_REF] Seeman | Pathogenesis of bone fragility in women and men[END_REF].

Figure 4 :

 4 Figure 4: Distribution of osteoporosis cases in major European countries (2010) (Hernlund et al., 2013).

Figure 5 :

 5 Figure 5: Representation of the age-adjusted indices rates in women in several countries in the world (Sibai et al. 2011).

Figure 6 :

 6 Figure 6: Representation of the age-adjusted indices rates in men in several countries in the world (Sibai et al. 2011).

Figure 7 :

 7 Figure 7: Causes of bone fractures.

Figure 8 :

 8 Figure 8: Characteristics of bones to resist to applied loads.

Figure 10 :

 10 Figure 10: Effect of trabecular microarchitecture on buckling strength.

Figure 12 :

 12 Figure 12: Bone mineral content gain in relation to age and sex[START_REF] Bailey | A Six-Year Longitudinal Study of the Relationship of Physical Activity to Bone Mineral Accrual in Growing Children: The University of Saskatchewan Bone Mineral Accrual Study[END_REF].

Figure 13 :

 13 Figure 13: Determinant of peak bone mass (Bonjour et al. 2009).

  found that a 12-month period of resistance training showed an improvement in the BMD of the arm. This change in arm BMD is positively related to the change in arm muscle mass. Thus, muscle contraction forces are beneficial for increasing bone mass and strength. Resistance training programs also influence bone health by increasing the levels of several anabolic hormones (GH, testosterone and IGF-1) which positively influence bone mass. Resistance training also decreases fat mass percentage and thus the level of inflammatory cytokines which are harmful for bone health.3.3 Exercise interventions during childhood, adolescence, adulthood and older age Meyer et al. (2013) showed in their longitudinal study that children who participated in school-based interventions presented a greater bone mineral content in their FN and TH and

3. 28

 28 Correlations between the percentage of variation of clinical and bone variables and the percentage of attendance of the recreational groupsThe percentages of variations of FN BMD, CSA and SI were significantly correlated to the percentage of attendance. No significant correlation was found concerning the other parameters.

1 . 1 1 1 . 3 . 2

 111132 conséquent, le football est considéré comme un sport à fort impact biomécanique, et de nombreuses études ont montré que sa pratique dans plusieurs populations augmente la formation osseuse à plusieurs sites (indiqués précédemment dans les tableaux). De plus, le football est pratiqué partout dans le monde. En effet, la participation au football est agréable et problèmes orthopédiques majeurs ou d'autres troubles qui affectent le métabolisme osseux, y compris le diabète.Design des 3 étudesLes 3 études comprenaient l'évaluation des paramètres anthropométriques, des paramètres osseux et des paramètres physiques.Le poids corporel a été mesuré en utilisant une balance mécanique standard avec une précision de 0,1 kg. La taille a été mesurée en position verticale à 0,5 cm près en utilisant un stadiomètre standard. L'IMC a été calculé en divisant le poids corporel par la taille au carré (kg / m 2 ). La composition corporelle [MM (Kg) / MG (%, kg)] a été évaluée par DXA. Le CMO (g) et la DMO (g/cm 2 ) ont été évalués dans différentes parties du corps. Le CMO corps entier (CE), la DMO corps entier (CE), la DMO rachis lombaire (L1-L4), la DMO hanche entière (HE), la DMO col fémoral (CF) et la DMO du radius (main droite) ont été évalués par DXA. De plus, les indices géométriques du col fémoral (CSA, CSMI, Z, SI et BR) ont été calculés par DXA. Les indices de résistance osseuse du col fémoral (CSI, BSI et ISI) ont été calculés par leurs formules spécifiques. Le temps du sprint de 10 m, la détente verticale (DV), le saut horizontal (HJ), la puissance des membres inférieurs, la consommation maximale d'oxygène, la force concentrique maximale des membres inférieurs : 1-RM demi-squat, la force concentrique maximale des membres supérieurs : 1-RM : développé couché et la force de préhension de la main droite ont été évaluées.La consommation calcique journalière (CCJ)(Fard ellone et al. 1991), la consommation protéique journalière (CPJ)[START_REF] Morin | A rapid selfadministered food frequency questionnaire for the evaluation of dietary protein intake[END_REF], la qualité de sommeil (PSQI)[START_REF] Buysse | The Pittsburgh Sleep Quality Index: a new instrument for psychiatric practice and research[END_REF]) et le niveau hebdomadaire d'activité physique[START_REF] Armstrong | Development of the World Health Organization Global Physical Activity Questionnaire (GPAQ)[END_REF] ont été évalués par des questionnaires validés pour tous les participants des études 1 et 2.Analyses statistiques :Les données ont été exprimées en moyenne ± la déviation standard pour tous les paramètres étudiés. Les différences entre les groupes ont été évaluées par une analyse de variance à une voie (ANOVA). Les corrélations ont été précisées par le test de Spearman pour les distributions non normales et par le test de Pearson pour les distributions normales, les valeurs de r ont été retenues. Des modèles d'analyse de régressions linéaires multiples ont été utilisés pour définir les meilleurs déterminants des paramètres osseux et les valeurs de r 2 ont été rapportées (étude 1). Des analyses de covariance à une voie (ANCOVA) ont été utilisées afin de comparer les variables osseuses entre les groupes après ajustement pour des covariants. Dans l'étude 3, pour juger d'éventuelles différences longitudinales dans les 4 groupes (RF60, RF30, FF et C) à la suite de l'entrainement, nous avons utilisé une analyse de mesure répétée bidirectionnelle de la variance (two-way-RM-Anova). Les pourcentages de variations des qualités physiques et des paramètres osseux ont été calculés pour les 4 groupes. Une valeur de p < 0,05 était exigée afin d'affirmer le caractère significatif des résultats. Les analyses statistiques ont été effectuées à l'aide du programme SigmaStat 3.1 (Jandel Corp., San Rafael, Californie). La puissance musculaire et la consommation maximale d'oxygène prédisent la densité osseuse dans un groupe d'hommes d'âge moyen. Objectif : Explorer les relations entre plusieurs variables de performance physique et les paramètres osseux dans un groupe d'hommes d'âge moyen. 'âge moyen ont participé à cette étude. Les paramètres anthropométriques, osseux et physiques ont été évalués. Les corrélations entre les variables de performance physique et les caractéristiques osseuses de la population étudiée ont été calculées. De plus, les corrélations entre les variables cliniques et les caractéristiques osseuses de la population étudiée ont été calculées. Corrélations entre les variables cliniques et les caractéristiques osseuses Le poids corporel a été corrélé aux plusieurs paramètres osseux : CMO CE, DMO CE, DMO HE, DMO CF, DMO radius, CSA, CSMI et SI. L'IMC était corrélé aux plusieurs paramètres osseux : le CMO CE, la DMO CE, la DMO HE, la DMO du radius total et le SI. La MM était positivement corrélée au CMO CE, DMO CE, DMO HE, DMO CF, DMO radius, CSA et CSMI. La MG était corrélée au CMO CE, la DMO CE, la DMO HE, la DMO radius et le SI. Le pourcentage de la MG était négativement corrélé au SI. La consommation protéique journalière était positivement corrélé à la DMO CE, à la DMO L1-L4 et à la DMO HE. L'activité physique (h/semaine) était positivement corrélée à la DMO L1-L4, la DMO HE, la DMO CF, la CSA, le CSMI et le SI. Corrélations entre les variables physiques et les caractéristiques osseuses. La puissance maximale des membres inférieurs était positivement corrélée à la CMO, la DMO CE, la DMO L1-L4, la DMO HE, DMO CF, DMO radius, CSA et CSMI. La force de la poignée (handgrip) était positivement corrélée au CMO CE, la DMO CE, la DMO CF, la DMO Radius, la CSA et le CSMI. La 1-RM demi-squat était positivement corrélé au CMO CE, la DMO CE, la DMO L1-L4, la DMO HE, DMO CF, CSA et CSMI. 1-RM Bench press était positivement corrélée au CMO CE, la DMO CE, la DMO CF, la DMO radius total, la CSA et le CSMI. Le sprint de 10 m était négativement corrélé à la DMO L1-L4, la DMO CF, la CSA, le CSMI et le SI. La VO2 max (L / min) était positivement corrélée à la BMC WB, la DMO CE, la DMO L1-L4, la DMO HT, la DMO CF, la CSA et le CSMI. Le VO2 max (ml / min / kg) était positivement corrélé au SI. Le saut horizontal n'était pas corrélé aux variables osseuses.

  d'activité physique était positivement corrélé au CSI, au BSI et à l'ISI. Le PSQI et l 'IMC étaient négativement corrélés au CSI et à l'ISI.

3. 2 3 . 3 . 6

 2336 Méthodes : 51 hommes d'âge moyen ont participé à cette étude. Ils ont été divisés en 4 groupes : Groupe d'hommes actifs (anciens joueurs de football ; FF n = 14), groupe de football récréatif 60 (RF60 ; n = 13), groupe de football récréatif 30 (RF30 ; n = 14) et le groupe témoin (C ; n = 10). 10 sujets ont abandonné pour différentes raisons (7 blessures dont 3 dans RF30 ; 3 dans La DMO CE a significativement diminué (p = 0,009) dans le groupe FF après une période d'un an. Aucun changement significatif n'a été trouvé concernant les autres paramètres cliniques et osseux. Paramètres de performance physique avant et après la période d'entraînement dans FF groupe Aucun changement significatif n'a été trouvé concernant les variables de performance physique en FF après 1 an de football récréatif. 3.3.7 L'effet du football récréatif sur les paramètres cliniques et osseux dans le groupe du football récréatif 30 (RF30) Après la période d'intervention d'un an, l'activité physique (minutes / semaine), le CMO CE, la DMO CF, la CSA, le CSMI, le Z, le SI, le CSI, le BSI et l'ISI ont augmenté de manière significative dans le RF30.3.3.8 L'effet du football récréatif sur les paramètres de performance physique dans le groupe de football récréatif 30 (RF30)La DV, l'1RM demi squat et le VO2 max absolu et relatif ont augmenté de manière significative. D'autre part, la force de préhension a diminué de manière significative.3.3.9 L'effet du football récréatif sur les paramètres cliniques et osseux dans le groupe du football récréatif 60 (RF60)Après la période d'intervention d'un an, l'activité physique (min / semaine), le CMO CE, la DMO L1-L4, la DMO HE, la DMO CF, le CSMI, le CSI, le BSI et l'ISI ont augmenté de manière significative dans RF60. En revanche, la DMO CE a considérablement diminué. absolue et relative a augmenté de manière significative mais la force de préhension a significativement diminué.

4 groupes 3 . 4 3 . 6

 43436 élevé dans RF60 et RF30 par rapport aux groupes C et FF et dans RF60 par rapport à RF30. Le pourcentage de variation de la DMO CF était significativement plus élevé dans le RF30 et le RF60 par rapport aux groupes C et FF. Les pourcentages de variation de SI, de CSI et d'ISI étaient significativement plus élevés dans RF30 par rapport au C.3.3.14 Pourcentages de variation des paramètres de performance physique dans les Le pourcentage de variation de la DV était significativement plus élevé dans RF30 par rapport à C. Le pourcentage de variation du 1-RM bench press était significativement plus élevé dans RF60 et FF par rapport au C. Les pourcentages de variation de la VO2 max absolus et relatifs étaient significativement plus élevés dans RF30 et RF60 par rapport aux groupes FF et C. Discussion et Conclusion Un an de pratique du football semble suffisant pour augmenter plusieurs paramètres de santé osseuse, en particulier au niveau du col fémoral chez les hommes d'âge moyen. Ce résultat est cliniquement important car les fractures du col du fémur sont les plus dangereuses chez l'homme et peuvent augmenter considérablement le risque de mortalité. Il semble que les deux groupes de football récréatif (RF60 et RF30) sont efficaces pour augmenter la DMO CF et la VO2 max absolue et relative chez les hommes libanais inactifs en bonne santé d'âge moyen. La plupart des bienfaits peut survenir en réponse à 2*30 minutes de football récréatif par semaine. Originalité et points forts de l'étude À notre connaissance, il s'agit de la première étude à comparer les effets de deux programmes d'entraînement de football récréatif chez des hommes d'âge moyen. Les résultats obtenus ont montré que ces types de programmes d'entraînement sont suffisants pour augmenter plusieurs paramètres de santé osseuse ainsi que la VO2 max. En conséquence, de tels types de programmes d'entraînement devraient être recommandés aux hommes d'âge moyen afin d'améliorer leur santé cardiovasculaire et musculo-squelettique.

4 .

 4 Cette thèse de doctorat menée sur un groupe d'hommes d'âge moyen montre principalement que :La VO2 max (L/min), la masse maigre et la puissance maximale des membres inférieurs sont les déterminants les plus puissants des variables osseuses chez les hommes d'âge moyen.La pratique antérieure du football est associée à des indices de résistance osseuse du col fémoral plus élevés (CSI, BSI et ISI) chez les hommes d'âge moyen.Le football récréatif à raison de 2 séances par semaine est une méthode efficace pour l'amélioration des paramètres de santé osseuse chez les hommes cinquantenaires.5. Perspectives :1 er axe : il serait intéressant de mener une étude longitudinale similaire avec un nombre plus élevé de participants et une durée d'entraînement plus longue dans laquelle nous ajouterons plusieurs questionnaires (liés au score de contraintes mécaniques, à la qualité de sommeil, à la qualité de vie, à l'apport en protéines et à la consommation de calcium) et plusieurs évaluations (comme l'évaluation du profil lipidique, de la régulation du glucose et des cytokines inflammatoires). Il serait également intéressant d'étudier les effets de l'arrêt de l'entraînement (désentraînement) sur ces paramètres dans la même population, d'étudier les effets du football récréatif sur les paramètres de santé osseuse chez les femmes du même âge et d'étudier les effets de la pratique d'autres sports collectifs (handball, basketball et volleyball) sur la performance physique et les paramètres de santé osseuse dans la même population.2 ème axe : il serait cliniquement important d'explorer l'efficacité de la pratique du football (Walking football) sur la composition corporelle, la force fonctionnelle, les paramètres de santé osseuse et la qualité de vie chez les sujets âgés sarcopéniques.3 ème axe : Comme le syndrome métabolique devient très fréquent chez les jeunes adultes âgés de moins de 40 ans, il serait judicieux d'explorer les effets de la pratique du football sur la composition corporelle, la glycémie, le profil lipidique sanguin, la pression artérielle et les variables de performance physique chez les jeunes adultes(30-39 ans) ayant un syndrome métabolique.

Table 1 :

 1 Osteoporosis' diagnostic criteria according to the World health organization. ........

Table 2 :

 2 Variables measured by DXA and their clinical importance. ...................................

Table 3 :

 3 Geometric indices of Beck

Table 1 :

 1 Osteoporosis' diagnostic criteria according to the World health organization.

Table 2 :

 2 Variables measured by DXA and their clinical importance.

	Variables measured by DXA Abbreviation	Clinical importance
	Bone mineral content	BMC	It is correlated to the
			mechanical strength of bone

(Beck et al., 1990)

		Abbreviation	Clinical importance
	Cross-sectional area	CSA	It is an index of the bone's
			ability to withstand axial
			compression.
	Cross-sectional moment of	CSMI	It is an index of structural
	inertia		rigidity of the bone.
	Cortical thickness	CT	It is a determinant of bone
			strength and the risk of
			osteoporotic fracture.
	Section modulus	Z	It reflects the flexural
			strength.
	Buckling Ratio	BR	It reflects cortical stability to
			deformation.

Table 4 :

 4 Karlamangla

's (2004)

bone resistance indices and their clinical importance.

Table 5 :

 5 The major modifiable and non-modifiable risk factors of osteoporosis.

	Major modifiable risk factors:	Major non-modifiable risk factors:
	Inadequate nutritional absorption ( vitamin	History of falls (Prior fracture)
	D deficiency, low calcium intake)
	Absence of physical activity	Genetics
	(immobilization)
	Low body mass index	Older age (increasing age)
	Cigarette smoking	Gender (female sex and postmenopausal
		status)
	Air pollution	Ethnicity
	Alcohol abuse	Reproductive factors (family history of
		osteoporosis)
	Stress
	Type 1 and 2 osteoporosis have to some extent different effect on bone loss. Type 1 appears
	to affect mostly trabecular bone, while type 2 affects both cortical and trabecular bone (Riggs

Table 6 :

 6 Examples of secondary osteoporosis.

1.3.2.1 Oral glucocorticoids

Table 7 :

 7 The prevalence distribution of osteoporosis in 27 European contries.

Table 8 :

 8 Total numbers of osteoporosis related deaths in 27 European countries.

Table 9 :

 9 Summary of longitudinal studies regarding the effects of soccer on bone in boys aged between 8 to 16 years.

	Authors and	Population	Methods	Results	Conclusion
	year
	Zouch et. al.	76 boys (10 to 13 years) were	-Soccer players played for	At T1:	1 year period of soccer in young male
	(2014)	divided into: -48 soccer players 22 prepubescent players (F1) 26 entered puberty players (F2) -28 control subjects divided as:	at least 3 years in a local club + completed 2-5 hours of training +1 competition game/week during the school year (1year study) + physical education at	Higher BMC at WB and weight bearing sites were found in both F1 and F2 compared to C1 and C2	showed that the combination of physical exercise and sexual impregnation stimulates more intensely bone formation at puberty compared to physical activity alone or sexual impregnation alone.
		13 Prepubescent control boys	school.
		(C1) 15 entered puberty control boys (C2)	-BMC was measured by DPX in many sites at: T0 and T1

Table 10 :

 10 Summary of longitudinal studies regarding the effects of soccer on bone in men aged between 20 and 54 years.

	Authors	Population	Methods	Results	Conclusion
	and year
	Krustrup	33 (aged 31-54 years) mild to	-STG subjects: participated	There were no significant	A 6 month period of soccer training
	et al.	moderate hypertension untrained	in 1h of soccer training:	changes in: fat mass and	effectively reduced blood pressure but
	(2013)	men participated in this study	2x/week for 6 months	lean body mass in the whole	did not show any effect on body
			-Subjects in DAG were	body and bone mineralization.	composition and bone mass in mild to
		They were randomly distributed	instructed by a cardiologist		moderate hypertension untrained men.
		to:	to perform regular physical	-Noticeable reductions were
		STG: Soccer training group	activity	observed in blood pressure.

4.3 Effects of soccer practice on bone parameters in male aged 60 years and above

While aging, bone loss is a universal phenomenal in both sexes. Physical activity may help to maintain or increase bone mass in elderly males.

Table 11 :

 11 Summary of longitudinal studies regarding the effects of soccer on bone parameters in elderly male (aged 60+ years). Effects of soccer on bone parameters in females aged between 30 and 61 years Several studies showed the effects of soccer training on bone parameters in female. In many studies (shown in table 4), long practice of soccer from 14-weeks to 1 year has a beneficial effect on bone parameters in healthy, mildly hypertensive, prediabetes women. Summary of these studies are shown in table12.

	Authors	Population	Methods	Results	Conclusion
	and year
		26 healthy sedentary men	Duration of the	-In F: there were an increase in:	An osteogenic effect was found in
	Helge et al. (2014)	(68.2 ± 3.2 years) participated in this study -They were randomly assigned into 3 groups:	intervention: 12 months Duration of the training: 45-60 min training for 2 to Tests: 3 times per week.	1.8% and 5.4 % in PF BMD after 4 and 12 months respectively WB-BMD did not change	elderly men who participated in recreational football for a duration of 4 months and an additional benefit was observed after 12 months.
		-F: Football group; n = 9	prior, at 4 and 12 months	-BMD and bone turnover
		-R: Resistance training group; n = 9	PF BMD and WB BMD were measured by DXA.	markers did not change in C and R.
		-C: non active Control group ;
		n = 8
	Uth et	Men having prostate cancer	Duration of the study	After a 12-week period:	A 12-week duration of football
	al. (2014)	undertaking androgen deprivation therapy ADT participated in this study and were randomly assigned into:	12-week 2 to 3x/week for 45-60 min.	FTG had a statistically significant difference in total body BMC and leg BMC.	training helps to maintain bone mass and induces an increase in the markers of bone formation in elderly men with PCa undergoing ADT.
		-FTG: Football training group n = 29; 67±7 years	Tests: DXA scan:
			total body BMC
		-C: Control group n = 28;	leg BMC
		66 ± 5 years	WB aBMD were
			determined

Table 12 :

 12 Summary of longitudinal studies investigating the effect of soccer practice on bone in female aged between 30 and 61 years.

	Authors	Population	Methods	Results	Conclusion
	and year
	Helge et	65 healthy untrained Danish	-Duration of the	-In F: Total vBMD in left tibia	A 14-week period of recreational
	al. (2010)	premenopausal women (36.5 ±7.7 years) participated in this study.	1 h twice a week intervention: 14 weeks Participants trained:	increased by 2.1±1.8% increased by 2.6±2.3% Total vBMD in the right tibia	football is beneficial in improving bone strength and decreasing fracture risk in premenopausal women.
		They were randomly assigned into 2 training groups:		-In R: total vBMD in left tibia
			Tests:	increased by 0.7±1.3%
		F: football; n=25	-Measurements of the vBMD were performed	Total vBMDin the right tibia increased by 1.1±1.5%
		R: running; n=25	using pQCT	No significant changes in C.
		Control group n=15	-aBMD in the total usingy DXA	trabecular vBMD had same results.
				In F: a 3±6% increase in peak
			-Jumping and dynamic	jump power. Increase in
			muscle strength were tested

Table 13 :

 13 Summary of cross sectional studies related to young female soccer and aged matched inactive controls aged between 15 to 27 years.

	Authors and year Population	Methods	Results	Conclusion
	Alfredson et al.	16 second-division female	DXA Scan: aBMD was	10.7 % increase in lumbar	Soccer training seems to have a
	(1996)	soccer players (20.9±2.2 years)	measured in many	spine BMD	beneficial site specific effect on
		(trained for about 6 h/week)	different sites.	-13.7 % increase in femoral	bone mass in young females.
				neck BMD
				-19.6% increase in Ward's
		13 inactive females (25.0±2.4 years): not participated in any kind of physical activity.		triangle BMD -8.2 % increase in femur BMD 8% increase in humerus
				BMD
				-12.6 % increase in distal
				femur BMD
				-12 % increase in proximal
				tibia BMD
				were shown in soccer players
	Ferry et al.	This study included:	DXA scan:	SOC:	Soccer has a beneficial effect on
	(2011)	-26 female swimmers (SWIM) aged: 15.9 ± 2 years	Body composition BMD	-significantly higher BMDs compared to swimmers	bone geometry and strength compared to a non-impact sport like swimming.
		-32 female soccer players (SOC) aged: 16.2 ± 0.7 years -15 female age-matched	hip structure analysis (HSA) program were also used	-CSMI, Z, BR were higher in all bone sites compared to swimmers
		controls		-Swimmers had (HSA) Z-
				scores below the normal
				values of the controls

Table 14 :

 14 Summary of cross sectional studies related to young male soccer and aged matched inactive controls aged between 18 and 30 years.

	Authors and year Population	Methods	Results	Conclusion
	Calbet et al.		Total and regional body	Compared to control subjects,	Football training in pre-pubertal
	(2001)	33 recreational male football	composition and many	football players showed:	ages in boys has a beneficial effect
		players (23 ± 4 yr) played football for the last 12 year	bone parameters at were evaluated by DXA	Higher total lean mass (8%)	on bone formation at weight-bearing sites.
				Higher whole-body 13%
		19 non-active subjects (24 ± 3		lower percentage body fat
		years)		13% higher L2-L4 BMC

Table 15 :

 15 Summary of cross sectional studies related to male soccer players and aged matched inactive controls aged between 10 to 15 years.

	Authors and year Population	Methods	Results	Conclusion
	McCulloch et al.	68 males and females
	(1992)	participated in this study and
		were divided into:
	(cross male and
	female)

Table 16 :

 16 Summary of cross sectional studies related to female soccer players and aged matched inactive controls aged between 10 to 18 years.

	Authors and year Population	Methods	Results	Conclusion
	Bellew and	64 female athletes (10 to 17	aBMD of the dominant	Soccer players showed
	Gehrig (2006)	years) participated in this study	limb calcaneus was	significantly higher BMD
		and were divided into:	measured by DXA.	compared to swimmers and
				weightlifters.
		Swimmers (n = 29)
		Soccer players (n = 16)
		weight lifters (n = 19)

Table 17 :

 17 Summary of cross-sectional studies related to male soccer players and aged matched inactive controls aged between 50 years and older.

	Authors and year Population	Methods	Results	Conclusion
	Finianos et al.	35 men (mean age 50 years)	DXA scan were done to	Significantly Higher CSI,	Former football players had higher
	(2020)	participated in this study and	determine body	BSI and ISI	composite indices of femoral neck
		were divided into:	composition and several	Were found in former players	strength compared to inactive
		20 inactive men	bone variables. CSI, ISI,	compared to controls after	middle-aged men.
		15 former football players	BSI were calculated	adjusting
				for physical activity level.
	Hagman et al.	140 healthy men joined this	DXA:	Compared to UE, FTE had:	Lifelong trained male football
	(2018)	study and were assigned into:	Proximal femur and a WB	-significantly higher FN,	players (65-80 years) showed
		FTE: 35 all-time football	BMD were determined.	wards, shaft, and total	greater BMD at many sites
		players (65 to 80 years)		proximal femur BMD	compared to aged matched
		FTY: 35 elite football players		-compared to UY, FTY had	untrained men. In addition, they
		(18 to 30 years)		BMD in all femoral regions	showed higher BMD in femoral
		UE: 35 age matched elderly		and total proximal femur in	trochanter and leg BMD than
		UY: 35 aged match young		both legs compared to UY	untrained young despite the 46
					years of age difference.

Table 18 :

 18 Design of the three studies.

	Title of the study	Objectives	Publication

Muscular power and maximum oxygen consumption predict bone density in a group of middle-aged men

	Abstract:
	Objective: The purpose of this study was to explore the relationships between several
	physical performance variables and bone parameters in a group of middle-aged men.
	Methods: 50 middle-aged men participated in this study. Body composition and bone
	variables were evaluated by DXA. Bone mineral density (BMD) was measured at the whole
	body (WB), total radius (TR), lumbar spine (L1-L4), total hip (TH) and femoral neck (FN).
	Geometric indices of femoral neck (FN) strength were also calculated by DXA. Handgrip
	strength, vertical jump, maximum power of the lower limbs (watts), maximal half-squat
	strength, maximal bench-press strength, sprint performance (10 m) and maximum oxygen
	consumption (VO2 max, L/min) were evaluated using validated tests. Results: VO2 max

(L/min), maximum power of the lower limbs, maximal half-squat strength, maximal benchpress strength, handgrip and lean mass were positively correlated to many bone parameters.

Lean mass was the strongest determinant of WB BMC. VO2 max (L/min) was the strongest determinant of WB BMD, TH BMD and FN BMD. Maximum power was the strongest determinant of total radius BMD. Conclusion: The current study suggests that VO2 max (L/ min), lean mass and maximum power of the lower limbs are the strongest determinants of bone variables in middle-aged men.

Study 2:

Composite Indices of Femoral Neck Strength in Middle-Aged Inactive Subjects Vs Former Football Players

	Abstract:
	The purpose of this study was to compare composite indices of femoral neck strength
	((compression strength index [CSI], bending strength index [BSI], and impact strength index
	[ISI]) in inactive middle-aged men (n = 20) and middle-aged former football players (n = 15).
	35 middle-aged men participated in this study. Body composition and bone variables were
	evaluated by dual-energy X-ray absorptiometry. Composite indices of femoral neck strength
	(CSI, BSI, and ISI) were calculated. Handgrip strength, vertical jump, maximum
	power of the lower limbs (watts), horizontal jump, maximal half-squat strength, maximal
	bench-press strength, sprint performance (10 meters), and maximum oxygen consumption

(VO2 max, ml/min/kg) were evaluated using validated tests. CSI, BSI, and ISI were significantly higher in football players compared to inactive men. Vertical jump, horizontal jump, maximal half-squat strength, VO2 max and sprint performance were significantly different between the 2 groups. CSI, BSI, and ISI remained significantly higher in football players compared to inactive men after adjusting for physical activity level. The current study suggests that former football practice is associated with higher composite indices of femoral neck strength in middle-aged men.

Study 3:

The Effects of a 1-year Recreational Football Protocol on Bone Mineral Density and Physical Performance Parameters in a Group of Healthy Inactive 50-year-Old Men.

  4 minutes of active rest. From 16 to 24 weeks, 3 min of rest were taken between the 13 minutes and 30 seconds time of play. From 24 to 32 weeks, only 2 minutes of rest were taken. Therefore, subjects played for 2 intervals of 14 minutes separated by 2 minutes of active rest. Finally, in the last 16 weeks, players played all the 30 min game with no rest. Players who were resting actively were asked to walk slowly.

	From 16 to 24 weeks, 9 min of rest were taken (3 rest period of 3 min). Therefore, subjects
	played for 4 intervals for approximately 13 minutes by 3 minutes of active rest. From 24 to 32,
	6 min of rest were taken (3 rest period of 2 min). Therefore, subjects played for 4 intervals for
	13.5 minutes separated by 2 minutes of active rest. Finally, in the last 16 weeks, players played
	all the 60 min game with no rest. Players who were resting actively were asked to walk slowly.
	For the RF30 group, participants also played a mini football game 2 times per week for 30 min

2 training sessions per week. All participants played football on the same mini football artificial grass pitch. All recreational football games were supervised by the author of the thesis. Training time of play was progressively increased each 8 weeks by decreasing the rest period during the game. For the RF60 group, participants played a normal mini-football game 2 times per week for 60 min in total. In the first 8 weeks of training, 15 min of rest (3 rest periods of 5 min) were taken. Therefore, the players played for four intervals of approximately 11 minutes separated by 5 minutes of active rest. From 8 to 16 weeks, 12 min of rest (3 rest period of 4 min) were taken. Therefore, subjects played for 4 intervals for 12 minutes separated by 4 minutes of active rest. in total. In the first 8 weeks of training, 5 min of rest were taken. Therefore, the players played 2 intervals of approximately 12 minutes separated by 5 minutes of active rest. From 8 to 16 weeks, 4 min of rest were taken. Therefore, subjects played for 2 intervals of 13 minutes separated by

Table 19 :

 19 Clinical characteristics and bone variables of the study population at baseline. Physical performance variables of the study population before the intervention CMJ and 10-m sprint were significantly higher in FF compared to C and RF30. HG was significantly higher in FF and RF30 compared to C. 1-RM half squat was significantly higher in FF compared to C, RF30 and RF60 and was higher in RF30 and RF60 compared to C. VO2 max (L/min) was significantly higher in FF compared to C.

		C n=10	FF n=11	RF30 n=10	RF60 n=10	p-value
		Mean ± SD	Mean ± SD	Mean ± SD	Mean ± SD
	Age (years)	51.8 ± 4.7	48.7 ± 3.1	48.8 ± 5.4	51.07 ± 5.1	P = 0.348
	Weight (kg)	84.8 ± 13.4	90.9 ± 9.5	94.3 ± 11.5	93.4 ± 18.0	P = 0.404
	Height (m)	1.68 ± 0.06 a	1.76 ± 0.05	1.74 ± 0.02	1.75 ± 0.07	P= 0.004
	BMI (kg/m 2 )	29.7 ± 4.2	29.1 ± 2.8	31.0 ± 3.4	30.3 ± 4.9	P = 0.713
	Lean mass
		53.6 ± 5.8	60.3 ± 4.9	59.2 ± 6.2	57.3 ± 7.6	P = 0.097
	(Kg)
	Fat mass
		29.0 ± 9.3	27.4 ± 6.0	32.5 ± 7.7	33.3 ± 1.1	P = 0.372
	(Kg)
	Fat mass
		33.4 ± 5.7	29.9 ± 4.2	34.0 ± 4.8	34.9 ± 5.0	P = 0.124
	percentage
	Physical
	activity	101.0 ± 23.3 132.2 ± 33.4 110.0 ± 26.6 105.5 ± 32.8	P = 0.088
	(min/week)
	WB BMC
		2836 ± 266 a	3283 ± 243	3087 ± 295	3095 ± 429	P= 0.002
	(g)
	WB BMD	1.281 ±	1.383 ±	1.295 ±	1.310 ±
						P = 0.109
	(g/cm 2 )	0.0788	0.0885	0.0898	0.137
	L1-L4 BMD	1.206 ±	1.332 ±	1.203 ±	1.241 ±
						P = 0.100
	(g/cm 2 )	0.138	0.134	0.0840	0.158

Table 20 :

 20 Physical performance variables of the study population before the intervention.

		C n=10	FF n=11	RF30 n=10	RF60 n=10	p-value
		Mean ± SD	Mean ± SD	Mean ± SD	Mean ± SD
	CMJ (cm)	32.6 ± 5.8 a,c	40.0 ± 3.0	34.3 ± 4.1	36.1 ± 4.2	P=0.004
	Maximum	1042.35 ±	1247.20 ±	1193.09 ±	1228.46 ±
	Power	129.9	135.5	131.0	183.6	P = 0.013
	(Watts)	a,f	0	8	0
	HG (kg)	43.1 ± 4.9 a,b	50.6 ± 6.9	52.0 ± 6.7	46.6 ± 5.5	P = 0.011
	1-RM half-	61.6 ±
			110.1 ± 21.0 86.6 ± 12.2	81.6 ± 12.9	P<0.001
	squat (kg)	12.5 a,b,c,d,f
	1-RM bench
		50.4 ± 11.0	59.1 ± 7.3	53.8 ± 9.7	53.3 ± 11.2	P = 0.266
	press (kg)
	10 m sprint performance (s)	2.166 ± 0.176 a,c	1.891 ± 3 0.081	0.132 2.072 ±	0.109 2.023 ±	P = <0.001
	VO2 max
	(L/min)

3.26 ± 0.43 a 3.73 ± 0.34 3.52 ± 0.31 3.55 0.37 P=0.045

  Body fat mass % was significantly lower in FF compared to control group (C+RF60+RF30).Physical activity (min/week), WB BMC, WB BMD, L1-L4 BMD, FN BMD, CSA, CSMI, Z. CSI, BSI and ISI were significantly higher in FF compared to the control group.

	VO2 max	38.843 ±	41.377 ±	37.970 ±	38.175 ±
					P = 0.332
	(ml/min/kg)	4.143	4.191	5.308	5.143
	Significant difference in bold: F vs C a ; CF30 vs C b ; F vs CF30 c ; F vs RF60 d ; RF60 vs RF30 e ;
	RF60 vs C f ; SD: standard deviation; CMJ: counter movement jump; HG: handgrip; RM:
	Repetition Maximum; VO2 max: maximum oxygen consumption.

3.3 Clinical characteristics and bone variables of the Former football group and the inactive controls (C, RF30 and RF60 combined) at baseline

Table 21 :

 21 Clinical characteristics and bone variables of the Former football group and the inactive controls (C, RF30 and RF60 combined) at baseline.

		C + RF30 + RF60 n=30	FF n=11	p-value
		Mean ± SD	Mean ± SD
	Age (years)	50.5 ± 5.1	48.7 ± 3.1	P = 0.279
	Weight (kg)	90.8 ± 14.7	90.9 ±9.5	P = 0.993
	Height (m)	172.63 ± 6.32	176.63 ± 5.98	P = 0.076
	BMI (kg/m 2 )	30.4 ± 4.1	29.1 ± 2.8	P = 0.361
	Lean mass (kg)	56.7 ± 6.7	60.1 ± 4.9	P= 0.120
	Fat mass (kg)	31.6 ± 9.3	27.4 ± 6.0	P= 0.176
	Fat mass
		34.1 ± 5.0	29.9 ± 4.2	P=0.019
	percentage
	Physical activity (min/week)	105.5 ± 26.9	132.2 ± 33.4	P=0.012
	WB BMC (g)	3006 ± 348	3283 ± 243	P=0.021
	WB BMD
		1.295 ± 0.102	1.383 ± 0.0885	P=0.016
	(g/cm 2 )
	L1-L4 BMD
		1.217 ± 0.127	1.332 ± 0.134	P=0.015
	(g/cm 2 )
	TH BMD (g/cm 2 )	1.091 ± 0.119	1.172 ± 0.0968	P=0.050

In bold, significant differences; SD: standard deviation; BMI: body mass index; WB: whole body; BMC: bone mineral content; BMD: bone mineral density; L1-L4: Lumbar spine; TH: total hip; FN: femoral neck; CSA: cross sectional area; CSMI: cross-sectional moment of inertia; Z: section modulus; SI: strength index; BR: buckling ratio; CSI: compression strength index; BSI: bending strength index; ISI: impact strength index.

Table 22 :

 22 Physical performance variables of the study population before the intervention.

	C +RF30+RF60 n=30	FF n=11	p-value
	Mean ± SD	Mean ± SD

Table 23 :

 23 Clinical and bone parameters before and after the training period in the control group.

	Control (n=10)	Before intervention	After intervention	p-value
		Mean ± SD	Mean ± SD

Table 24 :

 24 Physical performance variables at baseline and after the 1-year period in the control group.

	CONTROL (n=10)	Before intervention	After intervention	p-value
		Mean ± SD	Mean ± SD
	CMJ (cm)	32.6 ± 5.8	32.1 ± 5.7	P = 0.248
	Maximum Power
	(Watts)	1042.35 ± 129.94	1033.70 ± 127.91	P = 0.266
	HG (kg)	43.1 ±4.9	40.4 ±4.4	P = <0.001
	1-RM half-squat
		61.6 ± 12.5	60.0 ± 12.2	P = 0.195
	(kg)
	1-RM bench press
		50.4 ± 11.0	45.3 ± 11.8	P = 0.123
	(kg)
	10 m sprint
	performance (s)	2.166 ± 0.176	2.188 ± 0.180	P = 0.091
	VO2 max (L/min)	3.26 ± 0.43	3.23 ± 0.44	P = 0.060

Table 25 :

 25 Clinical and bone parameters before and after the training period in the former football group.

	FF (n=11)	Before intervention	After intervention	p-value
		Mean ± SD	Mean ± SD
	Weight (kg)	90.9 ± 9.5	89.0 ± 10.5	P = 0.104
	BMI (kg/m 2 )	29.1 ± 2.8	28.5 ± 3.2	P = 0.094
	Lean mass (kg)	60.3 ± 4.9	59.5 ± 4.1	P = 0.410
	Fat mass (kg)	27.4 ± 6.0	27.1 ± 7.5	P = 0.707
	Fat mass percentage	29.9 ± 4.2	29.7 ± 5.3	P = 0.766
	Physical activity (min/week)	132.2 ± 33.4	135.9 ± 32.8	P = 0.267
	WB BMC (g)	3283 ± 243	3304 ± 235	P = 0.244
	WB BMD (g/cm 2 )	1.383 ± 0.0885	1.327 ± 0.102	P = 0.009
	L1-L4 BMD (g/cm 2 )	1.332 ± 0.134	1.328 ± 0.133	P = 0.777

In bold, significant difference; SD: standard deviation; BMI: body mass index; WB: whole body; BMC: bone mineral content; BMD: bone mineral density; L1-L4: Lumbar spine; TH: total hip; FN: femoral neck; CSA: cross sectional area; CSMI: cross-sectional moment of inertia; Z: section modulus; SI: strength index; BR: buckling ratio; CSI: compression strength index; BSI: bending strength index; ISI: impact strength index.

Table 26 :

 26 Physical performance parameters before and after the training period in the former football group.

	FF (n=11)	Before intervention After intervention	p-value

Table 27 :

 27 Clinical and bone parameters before and after the training period in the recreational football 30 group.

	RF30 (n=10)	Before intervention	After intervention	p-value
		Mean ± SD	Mean ± SD

Table 28 :

 28 Physical performance parameters before and after the training period in the recreational football 30 group.

	RF30 (n=10)	Before intervention After intervention	p-value
		Mean ± SD	Mean ± SD
	CMJ (cm)	34.3 ± 4.1	36.7 ± 5.2	P = 0.026
	Maximum Power (Watts)	1193.09 ± 131.08	1222.55 ± 110.78	P = 0.151
	HG (kg)	52.0 ± 6.7	47.5 ± 6.3	P = <0.001
	1-RM half-squat
		86.6 ± 12.2	91.7 ± 15.0	P = 0.046
	(kg)
	1-RM bench press
		53.8 ± 9.7	53.5 ± 7.8	P = 0.773
	(kg)
	10 m sprint performance (s)	2.072 ± 0.132	2.013 ± 0.139	P = 0.067
	VO2 max (L/min)	3.52 ± 0.31	3.75 ± 0.30	P = <0.001

Table 29 :

 29 Clinical and bone parameters before and after the training period in the recreational football 60 group.

	RF60 (n=10)	Before intervention	After intervention	p-value
		Mean ± SD	Mean ± SD
	Weight (kg)	93.4 ± 18.0	91.9 ± 18.2	P = 0.154
	BMI (kg/m 2 )	30.3 ± 4.9	29.8 ± 5.0	P = 0.164
	Lean mass (kg)	57.3 ± 7.6	57.4 ± 8.1	P = 0.814
	Fat mass (kg)	33.3 ± 1.1	32.4 ± 1.1	P = 0.118
	Fat mass percentage	34.9 ± 5.0	34.2 ± 4.8	P = 0.095
	Physical activity (min/week)	105.5 ± 32.8	175.5 ± 21.2	P = <0.001
	WB BMC (g)	3095 ± 429	3158 ± 428	P = 0.016
	WB BMD (g/cm 2 )	1.310 ± 0.137	1.256 ± 0.0972	P = 0.018

Table 30 :

 30 Physical performance parameters before and after the training period in the recreational football 60 group.

	RF60 (n=10)	Before intervention After intervention	p-value

Table 31 :

 31 Clinical and bone parameters before and after the training period in the recreational football group (RF30+ RF60).

	RF30 + RF60 (n=20)	Before intervention	After intervention	p-value

Table 32 :

 32 Physical performance parameters before and after the training period in the recreational football 30 and 60 combined group.

	RF30+RF60 (n=20)	Before intervention After intervention	p-value
		Mean ± SD	Mean ± SD
	CMJ (cm)	35.1 ± 4.2	37.1 ± 5.2	P = 0.005
	Maximum Power (Watts)	1209.84 ± 154.60	1225.60 ± 156.20	P = 0.215
	HG (kg)	49.4 ± 6.6	45.5 ± 6.1	P = <0.001
	1-RM half-squat
		84.1 ± 12.5	88.2 ± 12.3	P = 0.013
	(kg)
	1-RM bench press
		53.6 ± 10.1	54.1 ± 9.7	P = 0.539
	(kg)
	10 m sprint performance (s)	2.049 ± 0.121	1.996 ± 0.117	P = 0.010

Table 33 :

 33 Differences in the percentages of variation of the clinical and bone variables among control, former football and recreational football 30 and recreational football 60 groups.

		C	FF	RF30	RF60	p-value
		n=10	n=11	n=10	n=10
		Mean ± SD	Mean ± SD	Mean ± SD	Mean ± SD
	Weight	-0.02 ± 1.59	-2.06 ± 3.71	-0.74 ± 2.40	-1.62 ± 3.70	P = 0.432
	BMI	-0.02 ± 1.59	-2.06 ± 3.71	-0.74 ± 2.40	-1.62 ± 3.70	P = 0.432
	Lean mass	-0.59 ±2.23 -1.03 ±4.49	0.10 ± 2.71	0.15 ± 2.38	P = 0.801
	Fat mass	0.39 ± 4.63 -2.13 ± 10.94 -2.04 ± 3.46	-2.44 ± 5.59	P = 0.782
	Fat mass %	0.47 ± 4.30	-1.06 ± 8.75	-1.41 ± 3.01	-1.75 ± 3.36	P = 0.810
	Physical	-0.01 ±	3.25 ± 8.62	53.16 ±	76.87± 38.38 P = <0.001
	activity	7.71 b,e,f,g,h		14.85
	(min/week)
	WB BMC	0.55 ± 2.02	0.66 ± 1.65	1.71 ± 1.31	2.09 ± 2.20	P = 0.168

.69 ± 17.77 b 9.25 ± 16.53 20.73 ± 18.38 6.67 ± 12.88 P = 0.020

	BSI	-2.04 ± 8.08 9.97 ± 28.78	12.47 ±	6.72 ± 6.97	P = 0.293
				12.86
	ISI	-1.45 ± 5.14 b 5.08 ± 11.88 8.92 ± 6.24	8.43 ± 8.05	P = 0.042
	In bold, significant difference: FF vs C a ; RF30 vs C b ; FF vs RF30 c ; FF vs RF60 d ; RF60 vs
	RF30 e ; RF60 vs C f ; RF30 vs FF g ; RF60 vs FF h ; SD: standard deviation; BMI: body mass
	index; WB: whole body; BMC: bone mineral content; BMD: bone mineral density; L1-L4:
	Lumbar spine; TH: total hip; FN: femoral neck; CSA: cross sectional area; CSMI: cross-
	sectional moment of inertia; Z: section modulus; SI: strength index; BR: buckling ratio; CSI:
	compression strength index; BSI: bending strength index; ISI: impact strength index.
		3.16 Differences in the percentages of variation related to physical performance
	parameters among the groups
	BR	-2.70 ± 41.40	-17.78 ±	12.17 ±	-12.52 ±	P = 0.332
			30.67	34.76	47.61
	CSI	-1.70 ± 5.42 b 4.81 ± 11.80 9.17 ± 5.85	7.20 ± 6.02	P = 0.029

Table 34 :

 34 Differences in the percentages of variation of the clinical and bone variables among control, former football and recreational football 30 and recreational football 60 groups.

		C	FF	RF30	RF60
		n=10	n=11	n=10	n=10	p-value
		Mean ± SD	Mean ± SD	Mean ± SD	Mean ± SD
	CMJ	-1.45 ± 3.83 b 1.69 ± 4.81	7.31± 8.26	3.59 ± 7.22	P = 0.026
	Maximum Power	-0.78± 2.18	-1.29 ± 3.43	2.79 ± 5.52	-0.12 ± 3.43	P = 0.090
	HG	-6.31 ± 1.95 -9.76 ± 16.73 -8.64 ± 4.63	-6.90 ± 3.24	P = 0.827

Table 35 :

 35 Differences among control, former football and recreational football groups combined in the percentages of variation of clinical and bone variables.

		C n=10	FF n=11	RF (30+60) n=20	p-value
		Mean ± SD	Mean ± SD	Mean ± SD
	Weight	-0.02 ± 1.59	-2.06 ± 3.71	-1.18 ± 3.07	P = 0.309

a ; RF(30+60) vs C b ; SD: standard deviation; BMI: body mass index; WB: whole body; BMC: bone mineral content; BMD: bone mineral density; L1-L4: Lumbar spine; TH: total hip; FN: femoral neck; CSA: cross sectional area; CSMI: cross-sectional moment of inertia; Z: section modulus; SI: strength index; BR: buckling ratio; CSI: compression strength index; BSI: bending strength index; ISI: impact strength index.

Table 36 :

 36 Differences in the percentages of variation related to physical performance parameters among control, formal football and the combination of the two recreational football groups.

	C n=10	FF n=11	RF (30+60) n= 20	p-value
	Mean ± SD	Mean ± SD	Mean ± SD

Table 37 :

 37 Differences in the percentages of variation related to clinical and bone parameters among control, recreational football 30 and recreational football 60 groups.

		C n=10	RF30 n=10	RF60 n=10	p-value
		Mean ± SD	Mean ± SD	Mean ± SD
	Weight	-0.02 ± 1.59	-0.74 ± 2.40	-1.62 ± 3.70	P= 0.431
	BMI	-0.02 ± 1.59	-0.74 ± 2.40	-1.62 ± 3.70	P= 0.431
	Lean mass	-0.59 ± 2.23	0.10 ± 2.71	0.15 ± 2.38	P= 0.653
				-2.449 ±
	Fat mass	0.39 ± 4.63	-2.04 ± 3.46		P= 0.349
				5.596
	Fat mass %	0.47 ± 4.30	-1.41 ± 3.01	-1.75± 3.36	P= 0.344
	Physical activity	-0.010 7.71 a,	53.16 14.85 76.87 38.38	P< 0.001
	(min/week)	b,c
		0.550 ±	1.713 ±	2.092 ±
	WB BMC				P= 0.183
		2.027	1.318	2.204
		-3.908 ±	-2.318 ±	-3.755 ±
	WB BMD				P= 0.636
		3.442	3.983	4.740
		2.072 ±	5.037 ±	2.686 ±
	L1-L4 BMD				P= 0.412
		4.787	7.127	2.542
		1.343 ±	1.735 ±	2.653 ±
	TH BMD				P= 0.559
		2.845	2.369	3.014
		-1.711 ±
			5.805 ±	5.071 ±	P= 0.008
	FN BMD	4.191
			4.690	7.012
		a,b
	Total Radius BMD	0.997 ± 2.336	-0.705 ± 2.548	1.107 ± 2.037	P= 0.166

Table 38 :

 38 Differences in the percentages of variation related to physical performance parameters among control, recreational football 30 and recreational football 60 groups.

		C n=10	RF30 n=10	RF60 n=10	p-value
		Mean ± SD	Mean ± SD	Mean ± SD
					0.025
	CMJ	-1.45 ± 3.83 b 7.31 ± 8.26	3.59 ± 7.22
	Maximum Power	-0.78 ± 2.18	2.79 ± 5.52	-0.12 ± 3.43	0.130
	HG	-6.31 ± 1.95	-8.64 ± 4.63	-6.90 ± 3.24	0.315
	1-RM half-
		-2.66 ± 5.89	5.81± 7.52	4.83 ± 8.57	0.045
	squat
	1-RM bench	-9.66 ±
			0.17 ± 7.15	2.85 ± 6.21	0.025
	press	13.77 a
	10 m sprint performance	1.

02 ± 1.69 b -2.79± 4.14 -2.15 ± 3.45 0.033

	VO2 max	-0.
	(L/min)

82 ± 1.25 a,b 6.56 ± 1.75 6.65 ± 1.76 <0.001

	3.21 Group * time effects on clinical and bone parameters in 4 groups (FF, C, RF30 and RF60)
	There was a group * time interaction in FN BMD and PA.
	-1.02 ±
	VO2 max		<0.001
	2.55 a,	6.97 ± 3.30	8.76 ± 4.76
	(ml/min/kg)
	b
	In bold, significant difference: RF60 vs C a ; RF30 vs C b ; RF60 vs RF30 c ; SD: standard deviation;
	CMJ: counter movement jump; HG: handgrip; RM: Repetition Maximum; VO2 max:
	maximum oxygen consumption.

Table 39 :

 39 A two-way repeated measures ANOVA of the clinical and bone parameters among all 4 groups.

			FF	C			RF30		RF60	F	P
		PRE	POST	PRE	POST	PRE	POST	PRE	POST
	Lean	60.1 ± 1.0 59.7 ± 1.0 53.6 ± 1.1 53.3 ± 1.1 59.2 ± 1.1 59.2 ± 1.1 57.3 ± 1.1 54.4 ± 1.1 0.686	0.566
	mass
	(Kg)
	Fat mass	27.4 ± 393 27.14 ±	29.0 ± 412 29.2 ± 412 32.5 ± 412 31.8 ± 412 33.3 ± 412 32.4 ± 412 0.616	0.609
			393
	(kg)
	Fat mass	29.9 ± 0.3 29.7 ± 0.3 33.4 ± 0.3 33.6 ± 0.3 34.0 ± 0.3 33.4 ± 0.3 34.9 ± 0.3 34.2 ± 0.3 0.541	0.657
	%
	Physical	132.2 ±	135.9 ±	101.0 ±	100.5 ±	110.0 ±	165.0 ±	105.5 ±	175.5 ±	126.112	<0.001
	activity	2.1	2.1	2.2	2.2	2.2	2.2	2.3	2.3
	(min/wee
	k)

Table 40 :

 40 A two-way repeated measure ANOVA of the physical performance variables among all 4 groups.

			FF	C		RF30	RF60	F	P
		PRE	POST	PRE	POST	PRE	POST	PRE	POST
	CMJ (cm) 40.0 ± 0.4 40.7 ± 0.4 32.6 ± 0.5 32.1 ± 0.5 34.3 ±0.5 36.7 ± 0.5 36.1 ± 0.5	37.6 ± 0.53	3.076	0.040
	Maximum Power (Watts)	1247.20 ± 9.37	1232.37 ± 9.37	1042.35 ± 9.83	1033.70 ± 9.83	1193.09 ± 9.83	1222.55 ± 9.83	1228.46 ± 10.36	1228.99 ± 10.36	2.033	0.127
	HG (kg)	50.6 ± 1.0 45.7 ± 1.0 43.1 ± 1.0 40.4 ± 1.0 52.0 ± 1.0 47.5 ± 1.0 46.6 ± 1.1 43.4 ± 1.1	0.464	0.709
	1-RM
	half-squat	110.1 ± 1.4	111.0 ± 1.4	61.6 ± 1.6 60.0 ± 1.6 86.6 ± 1.6 91.7 ± 1.6 81.6 ± 1.6 84.7 ± 1.6	1.629	0.201
	(kg)
	1-RM
	bench	59.1 ± 1.1 60.2 ± 1.1 50.4 ± 1.2 45.3 ± 1.2 53.8 ± 1.1 53.5 ± 1.1 53.3 ± 1.2 54.8 ± 1.2	3.162	0.037
	press (kg)
	10 m sprint	1.891 ± 0.0143	1.875 ± 0.0143	2.166 ± 0.0150	2.188 ± 0.0150	2.072 ± 0.0150	2.013 ± 0.0150	2.023 ± 0.0158	1.978 ± 0.0158	2.845	0.051

Table 41 :

 41 A two-way repeated measure ANOVA of the clinical and bone parameters among the former football, control and the combination of the recreational football groups.

	FF		C		RF (30+60)	F	P
	PRE	POST	PRE	POST	PRE	POST

Table 42 :

 42 A two-way repeated measure ANOVA of the physical performance variables among the former football, control and the combination of the recreational football groups.There was a group * time interaction in FN BMD, CSMI, CSI, BSI, ISI, SI and PA.

		FF		C		RF30 + RF60	F	P
		PRE	POST	PRE	POST	PRE	POST
	CMJ (cm)	40.0 ± 0.4	40.7 ± 0.4	32.6 ± 0.5	32.1 ± 0.5	35.1 ± 0.3	37.1 ± 0.3	4.188	0.023
	Maximum Power (Watts)	1247.20 ± 9.50	1232.37 ± 9.50	1042.35 ± 9.97	1033.70 ± 9.97	1209.84 ± 7.23	1225.60 ± 7.23	1.969	0.154
	HG (kg)	50.6 ± 1.0	45.7 ± 1.0	43.1 ± 1.0	40.4 ± 1.0	49.4 ± 0.7	45.5 ± 0.7	0.530	0.593
	1-RM half-
	squat (kg)	110.1 ± 1.4	111.0 ± 1.4	61.6 ± 1.6	60.0 ± 1.6	84.1 ± 1.1	88.2 ± 1.1	2.280	0.117
	1-RM bench
	press (kg)	59.1 ± 1.0	60.2 ± 1.0	50.4 ± 1.2	45.3 ± 1.2	53.6 ± 1.2	54.1 ± 0.8	4.499	0.018
	10 m sprint performance (s)	1.891 ± 0.0141	1.875 ± 0.0141	2.166 ± 0.0148	2.188 ± 0.0148	2.049 ± 0.0108	1.996 ± 0.0108	4.265	0.022

Table 43 :

 43 A two-way repeated measure ANOVA of the clinical and bone parameters among the control, recreational 60 and recreational 30 groups.

		C		RF30		RF60	F	P
		PRE	POST	PRE	POST	PRE	POST
	Fat mass (kg)	29.0 ± 412	29.2 ± 412	32.5 ± 412	31.8 ± 412	33.3 ± 412	32.4 ± 412	1.698	0.202

Table 44 :

 44 A two-way repeated measure ANOVA of the physical performance variables among the control, recreational 60 and recreational 30 groups. Differences in the time of attendance to game between both recreational groups

		C		RF30		RF60		F	P
		PRE	POST	PRE	POST	PRE	POST
	CMJ (cm)	32.6 ± 0.5	32.1 ± 0.5	34.3 ± 0.5	36.7 ± 0.5	36.1 ± 0.5	37.6 ± 0.5	4.016	0.030
	Maximum Power (Watts)	1042.35 ± 9.83	1033.70 ± 9.83	1193.09 ± 9.83	1222.55 ± 9.83	1228.46 ± 10.36	1228.99 ± 10.36	1.961	0.161
	HG (kg)	43.1 ± 1.0	40.4 ± 1.0	52.0 ± 1.0	47.5 ± 1.0	46.6 ± 1.1	43.4 ± 1.1	2.580	0.095
	1-RM half-
	squat (kg)	61.6 ± 1.6	60.0 ± 1.6	86.6 ± 1.6	91.7 ± 1.6	81.6 ± 1.6	84.7 ± 1.6	3.544	0.045
	1-RM bench
	press (kg)	50.4 ± 1.2	45.3 ± 1.2	53.8 ± 1.1	53.5 ± 1.1	53.3 ± 1.2	54.8 ± 1.2	3.075	0.064
	10 m sprint performance (s)	2.166 ± 0.0150	2.188 ± 0.0150	2.072 ± 0.0150	2.013 ± 0.0150	2.023 ± 0.0158	1.978 ± 0.0158	3.857	0.034

Table 46 :

 46 Correlations between the percentage of variation of the clinical and bone performance variables and percentage of attendance of the study population.

		% of attendance
	Weight	0.277
	Lean mass	0.304
	Fat mass	0.0481
	Fat mass %	-0.0200
	WB BMC	-0.168
	WB BMD	0.383
	L1-L4 BMD	0.250

Table 47 :

 47 Correlations between the percentage of variation of the physical performance variables and percentage of attendance of the recreational groups.

		% of attendance
	CMJ	0.0502
	Maximum Power	0.226
	Handgrip	-0.0655

Table 48 :

 48 Correlations between the percentage of variation of the physical performance variables and the percentage of variation of bone variables in RF60 and RF30.To our knowledge, our study is the first to compare the effects of two recreational football protocols (30 vs 60 min) on clinical, bone and physical parameters in middle-aged healthy Lebanese men. Our results are clinically important as we provide strategies to increase bone mass or prevent bone loss in subjects who will be at risk for osteoporosis later in life. In

		WB	TH	FN	CSMI	SI	CSI	BSI	ISI
		BMC	BMD	BMD	(mm 4 )	48	(g/kg-	(g/kg-	(g/kg-
		(g)	(kg/m 2 )	(kg/m 2 )			m)	m)	m)
	CMJ (cm)	-0.0247 -0.389	-0.174	-0.384	0.0956	0.274	0.269	0.418
	Maximum	0.283	-0.327	0.0106	-0.433	0.0540	0.152	0.347	0.197
	Power
	(watts)
	Handgrip	-0.0378 0.0628	0.0219	-0.116	-	-0.433	-0.495 -0.284
	(Kg)					0.00782
	1-RM half-	-0.164	-0.100 -0.0376	0.249	0.218	-0.118 -0.0483 -0.312
	squat (kg)
	1-RM BP	-0.168 -0.0584 -0.234 -0.0893 -0.210	0.121	0.0626	0.287
	(kg)

  Originality and strengths of the study Up to our knowledge, this is the first study to compare the effects of two recreational football training programs in middle-aged men. The results obtained showed that these types of training programs are sufficient to increase several bone health parameters as well as VO2 max. Accordingly, such types of training programs should be recommended to middle-aged men to improve their cardiovascular and musculoskeletal health.

	parameters and bone parameters, and it cannot confirm a causal relationship between former
	football practice and present CSI, BSI and ISI values. Second, DXA measurements are 2-
	dimensional in nature, but the true nature of bone is three-dimensional. Moreover, several
	bone health determinants (insulin-like growth factor, testosterone, insulin, leptin, vitamin D
	and PTH levels) were not controlled in these studies. Another limitation is the relatively small
	number of subjects. Moreover, heart rate and GPS monitoring (running speed, distance

covered at different speed, etc.) were absent in our study; we were not able to quantify each training session of recreational football. Finally, we did not use a physical activity questionnaire to measure the effect of mechanical strain on BMD.

1.4

Control group (CON): n=12 (45±4 years) -higher WB BMD and BMC -lower plasma triglycerides -higher HDL cholesterol -better Yo-Yo intermittentendurance level 1 -better 20-m sprint performance compared to CON no significant change for lean body mass were observed in both groups .

pre-menopausal women with mild hypertension. 4.5 Cross sectional studies related to female soccer players and inactive controls aged between 15 and 27 years Several cross-sectional studies were conducted on female soccer players and inactive aged matched controls. BMD in many sites, especially in weight bearing sites, was significantly higher in soccer players compared to controls (table 13). Soccer training seems to have a beneficial site specific effect on bone mass in young females. The percentage of variation in Physical activity (min/week) was significantly higher in RF60 and RF30 compared to C and in RF60 compared to RF30. FN BMD percentage of variation was significantly higher in the RF30 and RF60 compared to C. SI percentage of variation was significantly higher in RF30 compared to C. CSI and ISI percentages of variation were significantly higher in RF30 and RF60 compared to C. BSI percentage of variation was significantly higher in RF30 compared to C.

SECOND PART: PERSONAL CONTRIBUTION

GENERAL DISCUSSION

The main purpose of the PhD thesis was to compare the effect of two recreational football protocols (RF30: 2x30min vs RF60: 2x60min for 1 year) on bone health and physical performance parameters in a group of healthy middle-aged men.

The first study has defined new determinants of bone health parameters in middle-aged men.

Lean mass was the strongest determinant of WB BMC, VO2 max (L/min) was the strongest determinant of WB BMD, TH BMD and FN BMD while maximum power of the lower limbs was the strongest determinant of total radius BMD. Accordingly, VO2 max (L/min), lean mass and maximum power of the lower limbs are the strongest determinants of bone variables in middle-aged men.

The second study has mainly shown that former football practice is associated with higher composite indices of femoral neck strength (CSI, BSI and ISI) in middle-aged men. Hence, regular football practice before the young adulthood period may confer residual benefits in composite indices of femoral neck strength in middle-aged men.

The third study compared the effects of two recreational football protocols (RF30: 2x30min vs RF60: 2x60min for 1 year) on bone health and physical performance parameters in a group of middle-aged healthy men.

1.1 Analysis conducted on 3 groups (RF60, RF30 and C) significantly different between the former football players and the control group. This may be explained as we mentioned before in the "within group differences" paragraph, that FF participants are adapted to this type of stimulus and had higher baseline BMD compared to controls, so the benefits associated with physical training will be low. In addition, SI, CSI and ISI percentages of variation were significantly higher in RF30 compared to C. SI, CSI and ISI are related to the ratio FN BMD/weight; this ratio tends to increase in response to football training (El Hage et al., 2014b;El Hage, 2014). Concerning the physical performance parameters, the percentage of variation of the CMJ was significantly higher in RF30 compared to C but not in the RF60 and FF group. This may be due to the probability of having a higher training intensity in RF30 compared to the RF60 and the FF. Overall, there were no significant differences between both experimental groups (RF60 and RF30)

concerning the percentages of variations in bone health parameters and in physical performance variables. Hence, most of the health benefits can occur in response to 2*30 minutes of recreational football per week.

Within group differences

The longitudinal changes within groups for the control group, RF30 and RF60 have been previously discussed.

amusante avec une sensation modérée de fatigue physique après sa pratique (Krustrup et Krustrup, 2018). Cependant, les études longitudinales visant à étudier les effets de la pratique Abstract book page 404.

Summary

Effects of a 1-year recreational football protocol on bone mineral density and physical performance parameters in a group of healthy inactive 50-year-old men

The aims of this PhD thesis were to explore the relationships between several physical performance variables and bone parameters in a group of middle-aged men, to compare composite indices of femoral neck strength in inactive middle-aged men and aged-matched former football players and to explore the effects of a 1-year recreational football protocol on bone mineral density and physical performance parameters in a group of healthy inactive 50-year-old men. Three main studies have been conducted. The first study has shown that VO2 max (L/min), lean mass and maximum power of the lower limbs are the strongest determinants of bone variables in middle-aged men. The second study has shown that former football practice is associated with higher composite indices of femoral neck strength in middle-aged men. The third study has demonstrated that WB BMC, FN BMD, CSMI, CSI, BSI and ISI increased in both experimental groups (RF30 and RF60) but not in the control group. The percentages of variations in bone health parameters and in physical performance variables were not significantly different in both experimental groups. Recreational football is an effective method to improve bone health in middle-aged men. Keywords: Team sport; Prevention of osteoporosis; Men; Physical activity and bone; Muscular power; Aerobic fitness; Femur.

Résumé

Effets d'un protocole de football récréatif d'un an sur la densité minérale osseuse et les paramètres de performance physique chez un groupe d'hommes sains, inactifs et âgés de 50 ans

Les buts de cette thèse de doctorat étaient d'explorer les relations entre plusieurs paramètres de performance physique et les paramètres osseux chez un groupe d'hommes cinquantenaires, de comparer les ind ices de résistance osseuse du col fémoral chez un groupe d'hommes cinquantenaires inactifs et des anciens joueurs de football de même âge et d'explorer les effets d'un an de football récréatif sur la densité minérale osseuse et les paramètres de performance physique chez un groupe d'hommes cinquantenaires. Trois principales études ont été menées. La première étude a démontré que la VO2 max (L/min), la masse maigre et la puissance maximale des membres inférieurs sont les meilleurs déterminants des paramètres osseux chez les hommes cinquantenaires. La deuxième étude a démontré que l'ancienne pratique du football est associée à une augmentation des indices de résistance osseuse du col fémoral chez les hommes cinquantenaires. La troisième étude a démontré que le CMO CE, la DMO CF, le CSMI, le CSI, le BSI et l'ISI ont augmenté dans les deux groupes expérimentaux (RF30 et RF60) mais pas dans le groupe témoin. Les pourcentages de variation des paramètres osseux et des performances physiques n'étaient pas significativement différents entre les deux groupes expérimentaux. Le football récréatif est une méthode efficace pour l'amélioration des paramètres de santé osseuse chez les hommes cinquantenaires.

Mots clés : Sports collectifs ; Prévention de l'ostéoporose ; Hommes ; Activité physique et os ; Puissance musculaire ; Qualité aérobie ; Fémur.