High bone mineral density in male elite professional volleyball players

The aim of this study was to assess bone mass in male elite athletes participating in an impact loading sport (volleyball) and, in particular, to determine whether the asymmetric nature of this sport leads to differences in the skeletal tissue composition of the limbs. Fifteen male volleyball players (VP) (26 +/- 4 years, 192 +/- 6 cm, 87 +/- 9 kg; mean +/- SD) and 15 non-active control subjects (25 +/- 2 years, 177 +/- 8 cm, 72 +/- 11 kg; mean +/- SD) were studied. VP training sessions (3-6 days/week) included a variety of jumping and weightlifting exercises. The VP were taller and heavier than the control subjects (p<0.001). Whole-body bone mineral content (BMC) and lean mass were higher in VP after adjustment for body mass and height (p<0.001). Axial skeleton and limb BMC and bone mineral density (BMD) were higher in VP than in control subjects (p<0.05). Adjusted lumbar spine (L2-4) BMD was 14% higher in VP than in control subjects (p<0.05). Similarly, a much greater adjusted BMD was observed in the femoral neck of VP (24%, 20%, 27% and 20% for the femoral neck, intertrochanteric, greater trochanter and Ward's triangle subregions respectively; p<0.05). The dominant arm was slightly heavier (approximately 3%) and had 4% more muscle mass than the contralateral arm in both the VP (p<0.05) and control subjects (p<0.05). Greater BMC values (9%), BMD (7%) values and the area occupied by osseous pixels (5%) were recorded in the dominant arm as compared with the nondominant arm in VP (p<0.05). No differences between arms were observed in control subjects. Right and left leg BMC and BMD values were similar in control subjects while 4% higher BMC values were recorded for the left leg in the VP group (p<0.05). A close relationship between left leg muscle mass and BMD was observed in the femoral neck subregions of all the subjects (r = 0.81, 0.81, 0.78 and 0.79 for the femoral neck, intertrochanteric, greater trochanter and Ward's triangle subregions respectively; p<0.001; n = 30). These findings clearly demonstrate a considerably high BMC and BMD in professional volleyball players which seems to be related to the loading type of exercise they perform.