Sections View Full Chapter Figures Tables Videos Annotate Full Chapter Figures Tables Videos Supplementary Content + Download Section PDF ++ Erin Hartigan, PT, DPT, PhD, OCS, ATC ++ Associate Professor ++ Physical Therapy Department ++ University of New England ++ Portland, Maine ++ ++ David A. Scalzitti, PT, PhD ++ Assistant Professor ++ Program in Physical Therapy ++ George Washington University ++ Washington, DC