1. Institute of Health and Sport Sciences, University of Tsukuba, Tsukuba, Ibaraki 305, Japan,
2. Laboratory of Exercise and Sports Science, Department of Environmental Science, Yokohama City University, 22‐2, Seto, Kanazawa‐ku, Yokohama 236, Japan,
3. Faculty of Integrated Arts and Sciences, Hiroshima University, Higashihiroshima, Hiroshima 739, Japan