1 From the Discovery Center for Musculoskeletal Recovery, Schoen Adams Research Institute at Spaulding, Boston, Massachusetts (FA); Department of Physical Medicine & Rehabilitation, Spaulding Rehabilitation Hospital, Boston, Massachusetts (FA); Department of Physical Medicine & Rehabilitation, Harvard Medical School, Boston, Massachusetts (FA); Department of Physical Medicine & Rehabilitation, Mayo Clinic, Rochester, Minnesota (CT); Co-Director Rehabilitation Medicine Research Center, Mayo Clinic Rochester, Minnesota (CT); Department of Physical Medicine, Rehabilitation, and Sports Medicine, Department of Physiology, University of Puerto Rico School of Medicine, San Juan, Puerto Rico (WRF); and Editor-in-Chief, American Journal of Physical Medicine and Rehabilitation (WRF).