1. Course of Physical Therapy, School of Health Sciences, Faculty of Medicine, Kagoshima University, 8-35-1 Sakuragaoka, Kagoshima 890-8544, Japan
2. Department of Orthopedic Surgery, Faculty of Medicine, Kagoshima University, Japan
3. Fujiyoshi Orthopedic Hospital, Kagoshima, Japan
4. Faculty of Systems and Information Engineering, Center for Cybernics Research, University of Tsukuba, Ibaraki 305-8575, Japan