1. Program in Physical Therapy, Washington University School of Medicine, St. Louis, MO, USA
2. Department of Orthopaedic Surgery, Washington University School of Medicine, St. Louis, MO, USA
3. Department of Mechanical Engineering and Materials Science, Washington University School of Medicine, St. Louis, MO, USA
4. Division of Biostatistics, Washington University School of Medicine, St. Louis, MO, USA
5. Department of Physical Therapy, University of Pittsburgh, Pittsburgh, PA, USA