1. Department of Physical Therapy, University of Maryland School of Medicine, Baltimore, Maryland
2. Department of Health Evaluation Sciences, Division of Biostatistics and Epidemiology, University of Virginia School of Medicine, Charlottesville, Virginia
3. Department of Orthopedic Surgery, University of Maryland School of Medicine, Baltimore, Maryland
4. Department of Epidemiology and Preventive Medicine, University of Maryland School of Medicine, Baltimore, Maryland