Bone mineral density of 704 amateur sportsmen involved in different physical activities

The aim of the study was to analyze the relation between sports and bone ma ss. Seven hundred and four men with no history of chronic disease were ques tioned on their adolescent and adult sporting activities. Their total body (TB) and regional (head, spine, arms and legs) bone mineral density (BMD) w ere measured by dual-energy X-ray absorptiometry. BMD measurements and rati os of regional BMD to TB BMD were compared using a multiple regression anal ysis. Probands (mean age 30 years) were engaged in 14 sports activities: ru gby, soccer, other team sports, endurance running, fighting sports, bodybui lding, multiple weight-bearing activities, swimming, swimming with flippers , biking, rowing, climbing, triathlon and multiple mixed activities. They s tated that they were practising a physical activity at the amateur level: 7 .1 h/week between the ages of 11 and 18 years and 9 h/week between age 18 y ears and the day of the interview (no significant difference between physic al activities). Rowers and swimmers had low TB BMD (1.22 and 1.17 g/cm(2)) and low leg BMD (1.37 and 1.31 g/cm(2)). Participants in rugby, soccer, oth er team sports and fighting sports had a high TB BMD (1.27-1.35 g/cm(2)) an d high leg BMD (1.41-1.5 g/cm(2)). For head BMD, there was no stastistical difference among the different groups. Constructed ratios pointed out the s ite-specific adaptation of the skeleton: soccer player and runners had a hi gher leg ratio; bodybuilders, fighters, climbers and swimmers had a higher arm ratio; rugby players had a higher spine ratio. Head ratio was higher in nonweight-bearing sports (rowing, swimming) than in weightbearing sports ( rugby, team sports, soccer, fighting sports and bodybuilding). Thus the BMD and ratio differences among the 14 disciplines seem to be site-specific an d related to the supposedly high and unusual strains created at certain sit es during sport training by muscle stress and gravitational forces. Head ra tio is closely related to the type of practice; its value could predict whe ther sport participants have developed the maximal peak bone mass they coul d achieve.