1. Center for Injury Research and Prevention, The Children’s Hospital of Philadelphia, Philadelphia, Pennsylvania2University of Pennsylvania Perelman School of Medicine, Philadelphia
2. Center for Injury Research and Prevention, The Children’s Hospital of Philadelphia, Philadelphia, Pennsylvania
3. National Center for Injury Prevention and Control, Centers for Disease Control and Prevention, Atlanta, Georgia
4. University of Pennsylvania Perelman School of Medicine, Philadelphia4Sports Medicine and Performance Center, The Children’s Hospital of Philadelphia, Philadelphia, Pennsylvania