THE EFFECTS OF GYMNASTICS TRAINING ON BONE-MINERAL DENSITY

The purpose of this study was to examine the effect of 27 wk of gymnas tics training on bone mineral density (BMD), body composition, insulin -like growth factor I (IGF-I), and osteocalcin. Subjects were 11 femal e intercollegiate gymnasts and 11 controls. Dual energy x-ray absorpti ometry (Lunar DPX) was used to determine BMD (L2-L4 and femur) and to assess body composition. The gymnasts were significantly lower in weig ht (53.9 and 60.8 kg) and % body fat (22.6 and 30.6) compared with con trols. After training, body weights of gymnasts remained the same but there was a significant increase in lean tissue mass of 2.9 kg (6.7%, P < 0.05). No changes in body composition were observed in the control s. The gymnasts had significantly higher mean lumbar (1.321 vs 1.225), and femoral neck (1.163 vs 1.079) BMD (g.cm(-2)) than the controls. L umbar BMD increased significantly (1.3%) in gymnasts following trainin g but femoral neck BMD did not increase. No BMD changes occurred in th e control group. Regarding serum IGF-I, no differences were seen betwe en the groups or across time. Serum osteocalcin values were significan tly higher in the gymnasts than the controls, but no differences were found across time. In conclusion, gymnasts had significantly higher BM Ds than controls, and a significant increase in lumbar BMD was seen in the gymnasts following 27 wk of training.