1. Department of Physical Medicine and Rehabilitation, Penn State College of Medicine, Hershey, Pennsylvania, USA
2. Spinal Cord Injury and Disorders Center, Hunter Holmes McGuire VA Medical Center, Richmond, Virginia, USA
3. School of Kinesiology, University of Southern Mississippi, Hattiesburg, Mississippi, USA
4. Department of Public Health Sciences, Penn State College of Medicine, Hershey, Pennsylvania, USA