[1] Ctr Dis Control & Prevent, Natl Ctr Injury Prevent & Control, Div Unintent Injury Prevent, 4770 Buford Hwy NE,Mail Stop F62, Atlanta, GA 30341 USA
[2] Stanford Univ, Sch Med, Dept Emergency Med, Stanford, CA 94305 USA
[3] Univ Calgary, Dept Psychol, Calgary, AB, Canada
[4] Princeton Univ, Dept Athlet Med, Univ Hlth Serv, Princeton, NJ 08544 USA
[5] Univ Washington, Sch Med, Dept Rehabil Med, Seattle, WA 98195 USA
[6] Univ Washington, Sch Med, Dept Orthopaed, Seattle, WA USA
[7] Univ Washington, Sch Med, Dept Sports Med, Seattle, WA USA
[8] Univ Washington, Sch Med, Dept Neurol Surg, Seattle, WA 98195 USA