1. K Cernak, PT, DPT, MPH, is Physical Therapist, Division of Physical Therapy, Department of Rehabilitation Medicine, University of Washington Medical Center, 1959 NE Pacific St, Seattle, WA 98195 (USA)
2. V Stevens, PT, is Physical Therapist, Division of Physical Therapy, Department of Rehabilitation Medicine, University of Washington Medical Center
3. R Price, MSME, is Research Scientist, Department of Rehabilitation Medicine, University of Washington Medical Center
4. A Shumway-Cook, PT, PhD, FAPTA, is Professor, Division of Physical Therapy, Department of Rehabilitation Medicine, University of Washington Medical Center