1. ML Schenkman, PT, PhD, is Professor, Physical Therapy Program, Department of Rehabilitation Medicine, University of Colorado Health Sciences Center, 4200 E Ninth Ave, C244, Denver, CO (USA).
2. Dr Schenkman, Mr Clark, Dr Xie, and Dr Kuchibhatla provided concept/research design, writing, and data analysis. Ms Shinberg and Ms Ray provided data collection and recruited subjects. Dr Schenkman, Ms Shinberg, and Ms Ray provided project management. Ms Shinberg provided technical direction for data collection and reduction. Dr Schenkman provided fund procurement, facilities/equipment, and insti
3. K Clark, PT, MS, is a graduate student in the Department of Biostatistics, School of Public Health, University of North Carolina, Chapel Hill, NC. He was a graduate student in the Physical Therapy Program, Duke University, when this work was carried out
4. T Xie, PT, PhD, is Financial Consultant, MONY Group, Raleigh, NC. He was a graduate student in the Physical Therapy Program, Duke University, when this work was carried out
5. M Kuchibhatla, PhD, is Assistant Research Professor, Department of Bioinformatics and Biostatistics and Center for the Study of Aging and Human Development, Duke University Medical Center, Durham, NC
6. M Shinberg, PT, MS, is Physical Therapist, Shriner's Hospital for Children, Philadelphia, Pa. She was Engineer, Motion Analysis Laboratory, Duke Center on Aging, at the time this work was completed
7. L Ray, PT, MS, is Physical Therapist, Department of Physical Therapy, Duke University Medical Center