The effects of 12 wk exercise-training program on total and regional body composition, and bone mineral density (BMD) were assessed by dual-energy X-ray absorptiometry (DEXA) in mild obese 8 women [age 49.4±3.1 (SE) yr, BMI 27.2±0.5]. The exercise - training program results in substantial increase in predicted maximal oxygen uptake (28.1±2.5 to 35.8±2.5 ml/kg/min ; P<0.01). The total fat mass decreased by 3.6 kg (23.44±0.94 to 19.85±1.12kg ; P<0.01), and the total fat-free mass did not change (36.00±0.71 to 36.01±0.63 kg ; not significant) when measured by DEXA. Fat mass reduced in the arms (4.50±0.39 to 3.72±0.23 kg ; P<0.05), legs (5.19±0.39 to 4.52±0.44 kg ; not significant), and trunk (11.99±0.78 to 10.10±0.70 kg ; P<0.01) as a result of training. There were no significant changes in total (1.150±0.018 to 1.139±0.016), lumber spine (L 1-4 ; 1.101±0.035 to 1.087±0.033), and femoral neck BMD (0.856±0.031 to 0.847±0.032). In addition, osteocalcin (a marker of bone formation) and tartrate-resistant acid phosphatase (a marker of bone resorption) were measured before and after training to assess bone turnover. The exercise-training program resulted in a decrease in osteocalcin (9.67±0.98 to 7.82±0.98 ng/ml ; P<0.05) and in a increase in tartrate-resistant acid phosphatase (9.33±0.69 to 12.82±0.77 IU ; P<0.01).
　These findings confirmed that 12 wk of exercise-training, which results in decreases in total and regional fat mass, was not sufficient to increase total and regional BMD. Exrcise-training can increase bone resorption, and this does not appear to be accompanied by changes in total and regional BMD. The reason for this conflict will require further study.

DESCENTE SPORTS SCIENCE Vol.17/THE DESCENTE AND ISHIMOTO MEMORIAL FOUNDATION FOR THE PROMOTION SPORTS SCIENCE