1. Spaulding Rehabilitation Hospital, Spaulding National Running Center, Department of Physical Medicine and Rehabilitation, Harvard Medical School, Cambridge, Massachusetts, USA
2. Division of Adolescent Medicine, Department of Pediatrics, Stanford University, Stanford, California, USA
3. University of North Carolina School of Medicine, Chapel Hill, North Carolina, USA
4. Division of Epidemiology, Department of Health Research and Policy, Stanford University, Stanford, California, USA
5. Boswell Human Performance Laboratory, Department of Orthopaedic Surgery, Stanford, California, USA
6. Division of Physical Medicine and Rehabilitation, Department of Orthopaedic Surgery, Stanford University, Stanford, California, USA