The purpose of this study was to quantify the severity of head impacts sustained by individual collegiate football players and to investigate differences between impacts sustained during practice and game sessions, as well as by player position and impact location. Head impacts (N = 184,358) were analyzed for 254 collegiate players at three collegiate institutions. In practice, the 50th and 95th percentile values for individual players were 20.0 g and 49.5 g for peak linear acceleration, 1187 rad/s2 and 3147 rad/s2 for peak rotational acceleration, and 13.4 and 29.9 for HITsp, respectively. Only the 95th percentile HITsp increased significantly in games compared with practices (8.4%, p = .0002). Player position and impact location were the largest factors associated with differences in head impacts. Running backs consistently sustained the greatest impact magnitudes. Peak linear accelerations were greatest for impacts to the top of the helmet, whereas rotational accelerations were greatest for impacts to the front and back. The findings of this study provide essential data for future investigations that aim to establish the correlations between head impact exposure, acute brain injury, and long-term cognitive deficits.
Joseph J. Crisco (Corresponding Author), Bethany J. Wilcox, and Jason T. Machan are with the Bioengineering Laboratory, Department of Orthopaedics, the Warren Alpert Medical School of Brown University and Rhode Island Hospital, Providence, RI. Thomas W. McAllister is with the Department of Psychiatry, Geisel School of Medicine at Dartmouth, Lebanon, NH. Ann-Christine Duhaime is with Pediatric Neurosurgery, Children’s Hospital at Dartmouth, Dartmouth Hitchcock Medical Center, Hanover, NH. Stefan M. Duma and Steven Rowson are with Center for Injury Biomechanics, Virginia Tech–Wake Forest, Blacksburg, VA. Jonathan G. Beckwith and Jeffrey J. Chu are with Simbex, Lebanon, NH. Richard M. Greenwald is with Simbex, Lebanon, NH, and with Thayer School of Engineering, Dartmouth College, Hanover, NH.
Conflict of Interest Disclosure: Joseph J. Crisco, Richard M. Greenwald, and Simbex have a financial interest in the instruments (HIT System, Sideline Response System [Riddell, Inc]) that were used to collect the biomechanical data reported in this study.