1. Department of Physical Medicine & Rehabilitation, University of Pittsburgh, Pittsburgh, Pennsylvania
2. Centers for Rehab Services, University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania
3. Department of Bioengineering, University of Pittsburgh, Pittsburgh, Pennsylvania
4. Department of Physical Therapy, University of Pittsburgh, Pittsburgh, Pennsylvania
5. Department of Kinesiology and Community Health, University of Illinois at Urbana-Champaign, Champaign, Illinois