It is well known that the regular aerobic exercise training has a certain effect to decrease the adipose tissue. However, it is difficult to evaluate the exercise training per se on the body compositional change due to the contamination effect derived from the change of other factors (e.g., the diet and seasonal change) during the training period in humans. Therefore, to assess the effect induced by the low-intensity exercise training per se, we employed one-legged training model using an alternative leg as a control, and measured the cross-sectional area of fat, muscle and bone in both thighs (50 % of the thigh distance) before and after the training. Eight young sedentary women (aged: 21-23 yr) were participated in the 12 weeks training program. Each subject had the supervised 60-min one-legged cycle ergometer training threetimes a week. The training or non-training leg (TL or NTL) was assigned randomly, and the exercise intensity was selected as 40 % of peak VO₂ (i.e., below AT：anaerobic threshold) at the start of training. Before and after the training, the subjects performed one-legged (using TL or NTL) and two-legged incremental cycle exercise tests until exhaustion to determine the peak VO₂. Each compositional area of both thighs were evaluated by our developmental ultrasound-measuring system. As a result, there was no essential difference of the fat area of both thighs at the end of training (TL : 68.6 ± 17.8 vs NTL : 68.3 ± 18.5 cm²) . The remaining (muscles and fat) and the total areas also showed no differences between both thighs, as same as the body mass and LBM (lean body mass). Only significant improvement was noticed in the duration time on one-legged cycle incremental exercise after training (TL : 1049 ± 122 vs NTL : 930 ± 109 s, p<0.05). The results show that low-intensity one-legged aerobic training can not induce any body compositional change in the trained thigh, while some peripheral factor may be improved the endurance rather than the O₂ transport.

DESCENTE SPORTS SCIENCE Vol.20/THE DESCENTE AND ISHIMOTO MEMORIAL FOUNDATION FOR THE PROMOTION SPORTS SCIENCE