Concussion Mechanisms and Activities in Youth, High School, and College Football.

Our purpose was to determine concussion mechanism and activity differences among three cohorts of football players: youth, high school, and college. Participants in this prospective cohort study were youth (ages 5-14 years, 118 teams, 310 team-seasons), high school (96 teams, 184 team-seasons), and college (34 teams, 71 team-seasons) football players. Athletic trainers collected athlete-exposure (AE) and concussion data during the 2012-2014 seasons. Injury mechanism referred to the object that made contact with the concussed player, resulting in the concussion. Injury activity referred to the type of football-specific activity that the player was involved in when the concussion was sustained. Injury proportion ratios (IPR) compared distributions of concussion mechanisms and activities among age levels. A total of 1429 concussions were reported over 1,981,284 AE across all levels (Rate: 0.72/1000AE). Overall, most concussions were caused by player contact (84.7%). During games, a greater proportion of youth football concussions (14.7%) were caused by surface contact than high school (7.3%, IPR = 2.02; 95% confidence interval [CI]: 1.10-3.72) and college (7.1%, IPR = 2.07, 95% CI: 1.02-4.23) football. Compared with college football concussions (90.2%), a smaller proportion of youth (80.0%, IPR = 0.89, 95% CI: 0.79-0.99) and high school (83.2%, IPR = 0.92, 95% CI: 0.86-0.99) football concussions were caused by player contact. A greater proportion of game youth football concussions (42.1%) occurred while an individual was being tackled than occurred in high school (23.2%, IPR = 1.81, 95% CI: 1.34-2.45) and college (23.0%, IPR = 1.83, 95% CI: 1.29-2.62) football. Findings were similar during practices. Compared with college football game concussions (15.8%), a smaller proportion of youth (6.3%, IPR = 0.40, 95% CI: 0.17-0.93) and high school (9.5%, IPR = 0.60, 95% CI: 0.38-0.95) football game concussions occurred while an individual was being blocked. Concussion mechanism and activity differences should be considered when developing concussion prevention and sport-safety methods specific to different age levels, in order to maximize effectiveness.