1. MN Orlin, PT, MS, PCS, is Assistant Professor, Department of Rehabilitation Sciences, MCP Hahnemann University, 245 N 15th St, MS 502, Philadelphia, PA 10102 (USA).
2. TG McPoil, PT, PhD, ATC, is Professor and Co-Director, Gait Research Laboratory, Department of Physical Therapy, Northern Arizona University, Flagstaff, Ariz