抄録
The purpose of the present study is to investigate the changes of calcaneal bone mass and leg extension power by muscular strength training and de-training. Subjects were eleven women (aged range 18 to 19 years) with low body mass index (mean BMI=17.4). They participated in our experiments after giving their informed consent. The muscular strength training was performed by leg press, leg extension and leg curl using machines respectively. The process of the experiment consisted of two times control experiments (C1,C2) before training, for a nine weeks training period (T-period) and for a six months de-training period (DeT-period). Calcaneal bone mass, leg extension power and body composition were measured in C1, C2, after T-period and after DeT-period. Relative calcaneal bone mass (%) was calculated by means of standard value of seventeen-aged women bone mass in this study. The mean value of the bone mass of eleven subjects after T-period increased by 6.5% to 88.8% as compared with that of C2 (82.3%). And the value of the bone mass after DeT-period decreased by 5.5% to 83.3% as compared with that after T-period. In the corresponding the change of the bone mass values, the mean value of the leg power extension also changed in C1, C2, after T-period and after DeT-period. However, the correlation between the rate of the change of bone mass and the rate of the change of leg extension power in individual subjects was not observed. It was conjectured that quantity of harder mechanical stress as muscular strength training influences calcaneal bone mass in this study. [J Physiol Sci. 2007;57 Suppl:S245]
