1. Department of Community Health Sciences, Kobe University Graduate School of Health Sciences, Kobe, Japan.
2. Department of Cardiovascular Rehabilitation, National Cerebral and Cardiovascular Center, Suita, Japan.
3. Department of Rehabilitation, Tanabe Orthopedics, Osaka, Japan.
4. BackTech, Inc., Tokyo, Japan.
5. Department of Rehabilitation, Kobe Mariners Hospital, Kobe, Japan.