1. Department of Physical Therapy, Neumann College, One Neumann Drive, Aston, PA 19014, USA. Tel.: ; Fax: ; E-mail: Lsilvers@neumann.edu
2. Gait Study Center, Department of Orthopedics and Medicine, Temple University School of Podiatric Medicine, Philadelphia, PA, USA
3. Department of Rehabilitation Sciences, MCP Hahnemann University, Philadelphia, PA, USA