1. JM VanSwearingen, PT, PhD, is Associate Professor of Physical Therapy, Department of Physical Therapy, School of Health and Rehabilitation Sciences, University of Pittsburgh, 6035 Forbes Tower, Pittsburgh, PA 15260 (USA).
2. JS Brach, PT, PhD, GCS, is Clinical Assistant Professor of Physical Therapy, Department of Physical Therapy, School of Health and Rehabilitation Sciences, University of Pittsburgh, and a postdoctoral fellow, Department of Epidemiology, Graduate School of Public Health, University of Pittsburgh