1. TE Johnston, PT, PhD, MBA, is Research Specialist, Shriners Hospitals for Children, 3551 N Broad St, Philadelphia, PA 19140 (USA)
2. AE Barr, PT, DPT, PhD, is Associate Professor, College of Health Professions, Temple University, Philadelphia, Pa
3. SCK Lee, PT, PhD, is Research Assistant Professor, Department of Physical Therapy, University of Delaware, Newark, Del, and Research Associate, Shriner's Hospitals for Children