1. JE Berlin, PT, MPT, is Research Associate and Instructor, Department of Physical Therapy, University of Pittsburgh, 6035 Forbes Tower, Pittsburgh, PA 15260 (USA).
2. KL Storti, MS, MPH, is Research Associate, Department of Epidemiology, Graduate School of Public Health, University of Pittsburgh
3. JS Brach, PT, PhD, GCS, is Assistant Professor, Department of Physical Therapy, University of Pittsburgh