1. Department of Exercise and Sport Science, National Center for Catastrophic Sports Injury Research, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
2. Special Olympics International, Washington, DC, USA
3. Department of Family Medicine, Center for Sports Cardiology, University of Washington, Seattle, WA, USA
4. Department of Epidemiology, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
5. Department of Exercise and Sport Science, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
6. Injury Prevention Research Center, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
7. Matthew Gfeller Center, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
8. Cantu Concussion Center, Emerson Hospital, Concord, MA, USA