Sections View Full Chapter Figures Tables Videos Full Chapter Figures Tables Videos Supplementary Content Download Section PDF ++ Susan B. O'Sullivan, PT, EdD ++ Professor Emerita ++ Department of Physical Therapy ++ College of Health Sciences ++ University of Massachusetts Lowell ++ Lowell, Massachusetts + ++ Thomas J. Schmitz, PT, PhD ++ Professor Emeritus ++ Department of Physical Therapy ++ School of Health Professions ++ Long Island University ++ Brooklyn Campus ++ Brooklyn, New York