1. Graduate School of Comprehensive Human Sciences, Doctoral program of Sports Medicine, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8574, Japan
2. Taekwondo Major School of Sports Science, University of Dankook; San 29 Anseo-dong, Cheonan-si Choongnam 330-714, Korea
3. Institute for Biomedical Engineering Consolidated Research Institute for Advanced Science and Medical Care, University of Waseda, 513 Waseda-tsurumaki, Shinjuku, Tokyo 162-0041, Japan