1. OY Kwon, PT, PhD, is Assistant Professor, Department of Rehabilitation Therapy, College of Health Science, Yonsei University, Wonju-si, Kangwon-do, Korea. Dr Kwon was a postdoctoral fellow at Movement Science Lab, Program in Physical Therapy, Washington University School of Medicine, St Louis, Mo, when this project was conducted
2. MJ Mueller, PT, PhD, is Associate Professor, Program in Physical Therapy, Washington University School of Medicine, 4444 Forest Park Blvd, Campus Box 8502, St Louis, MO 63110-2292 (USA).