However, we have recently also reported, in a longitudinal study, that men who start to exercise after the age of 18 years, as in the resistance training group, can increase their adult aBMD, vBMD, and cortical bone size [38]. Muscle forces and gravitational loading can affect bone mass [39], and

both the magnitude and intensity of the loading seem to be important for the osteogenic effect. We have previously reported that gravitational loading is associated with trabecular learn more microstructure and cortical bone at the distal tibia in young adult men [37]. When playing soccer, the skeleton is exposed to irregular dynamic loading from different directions. In agreement with previous studies in both animals and humans, we found that this type of bone-loading activity was related to higher BMD and favorable bone geometry [3, 28]. In the present study, we analyzed a subgroup exposed to low gravitational loading via exercise but with high muscle force. A previous study demonstrated that muscle strength seems to have a positive effect on aBMD of the insertion site of the quadriceps muscle in adolescent

boys [40]. Cohort studies have demonstrated that physical training before and CX 5461 during puberty are associated with increased bone acquisition in children and young adults [13, 41, 42]. However, the skeleton of older persons seems to be less adaptive to physical activity-induced mechanical loading applied to it [3, 43]. According to previous studies, power-lifting female athletes show no significant bone gain compared to nonathletic female subjects [18, 29]. In contrast, other studies have shown significantly higher aBMD in elite male weightlifters compared to age-matched controls of both nonathletic [44, 45] and recreational low-intensity resistance training young men [46]. However, the terms “weightlifting” and “power lifting” refer to competitive sports that involve exercise with heavy loads and attempts Protein kinase N1 to lift maximal amounts of weight, while the sport of “bodybuilding” has

the goal to maximize muscle size, symmetry, and definition. These terms should, therefore, be distinguished from the term “resistance training” with the design to enhance health, fitness, and sports performance [30]. Thus, habitual bodybuilding and resistance training may not be expected to be HSP targets beneficial for bone health, whereas exercise for competitive weightlifting and power lifting to obtain maximal power might be beneficial. In the present study, the resistance training men did not differ in any bone parameter, in either weight-bearing or nonweight-bearing bone, compared to nonathletic men. In addition, we found no significant differences in daily transportation, sedentary behavior, or occupational physical load between the groups of men compared.