1. Institute for Integrated Sports Medicine, Keio University School of Medicine, 35 Shinanomachi, Shinjuku-ku, Tokyo 160-8582, Japan
2. Department of Neurology, Mitate Hospital, Fukuoka, Tagawa 826-0041, Japan
3. Department of Orthopaedic Surgery, Keiyu Orthopaedic Hospital, Gunma 374-001, Japan