1. The Micheli Center for Sports Injury Prevention, Waltham, MA
2. Division of Sports Medicine, Department of Orthopedics, Boston Children's Hospital, MA
3. Department of Rehabilitation Sciences, College of Health Sciences, University of Kentucky, Lexington
4. Department of Biostatistics, College of Public Health, University of Kentucky, Lexington
5. The SPORT Center, Division of Sports Medicine, Cincinnati Children's Hospital Medical Center, OH
6. Departments of Pediatrics and Orthopaedic Surgery, University of Cincinnati, OH
7. Department of Orthopaedics, University of Pennsylvania, Philadelphia
8. Mayo Clinic Biomechanics Laboratories and Sports Medicine Center, Departments of Orthopedics, Physical Medicine and Rehabilitation and Physiology & Biomedical Engineering, Mayo Clinic, Rochester and Minneapolis, MN