1. DA Ulrich, PhD, is Professor, Department of Kinesiology, and Director, Center for Motor Behavior and Pediatric Disabilities, University of Michigan, 401 Washtenaw Ave, Ann Arbor, MI 48109-2214 (USA)
2. MC Lloyd, MA, CW Tiernan, MS, and JE Looper, PT, MSPT, are doctoral candidates in the Department of Kinesiology, University of Michigan, and are associated with the Center for Motor Behavior and Pediatric Disabilities
3. RM Angulo-Barroso, PhD, is Associate Professor, Department of Kinesiology, University of Michigan, and is associated with the Center for Motor Behavior and Pediatric Disabilities