1. JS Brach, PT, PhD, GCS, is Assistant Professor, Department of Physical Therapy, School of Health and Rehabilitation Sciences, University of Pittsburgh, 6035 Forbes Tower, Pittsburgh, PA 15260 (USA).
2. JM VanSwearingen, PT, PhD, is Associate Professor, Department of Physical Therapy, School of Health and Rehabilitation Sciences, University of Pittsburgh
3. AB Newman, MD, MPH, is Associate Professor, Department of Geriatric Medicine, School of Medicine, and Department of Epidemiology, Graduate School of Public Health, University of Pittsburgh
4. AM Kriska, PhD, FACSM, is Associate Professor, Department of Epidemiology, Graduate School of Public Health, University of Pittsburgh