Head Impact Exposure Of A Youth Football Team Over Eight Consecutive Seasons

Abstract

There is growing evidence for the potential risk of brain injury due to repetitive, subconcussive head impacts in youth football. Despite increased awareness and efforts to reduce head impact exposure (HIE) in this sport, an objective, longitudinal assessment of HIE in youth football is noticeably lacking. PURPOSE: To examine HIE in middle school football players over multiple seasons. METHODS: HIE was evaluated in 94 middle school football players (11-14 yr) who participated in a community youth tackle football program with the same coaching staff over eight consecutive seasons (2012-2019). HIE was assessed using the Head Impact Telemetry System, which utilizes a helmet-mounted array of six single-axis accelerometers to measure head impact frequency, severity (linear and rotational acceleration) and location. Mean head impacts per player per session (HIPS) and median head impact severity measures were compared across seasons. RESULTS: There were 33,519 head impacts registered throughout the eight-year study. Mean practice HIPS and overall HIPS decreased each season, resulting in a 79.4% (10.7 vs. 2.2 HIPS, P < 0.001) and 74.4% (12.5 vs. 3.2 HIPS, P < 0.001) decrease, respectively, from 2012-2019. Mean game HIPS were reduced by 60.6%, with a significant difference observed between 2012-14 and 2015-19 (17.7 ± 0.7 vs. 9.5 ± 2.1 HIPS, P < 0.01). Median linear and rotational acceleration remained relatively unchanged during the study. Head impacts greater than 80 g decreased every season from 103 in 2012 to 11 in 2019. Nine subjects experienced physician-diagnosed concussions during the study, resulting in a concussion rate of 1:3724 head impacts. CONCLUSIONS: Head impacts incurred by youth football players from a community football league decreased considerably over eight seasons, with players in the final year of the study sustaining approximately one-fourth the head impacts per session as players experienced during the first year. The greatest and most consistent decline occurred in practices, though players also had much fewer head impacts in games. While factors associated with observed reductions in head impact exposure were not investigated, these results suggest that coaching and/or player behavior can be modified to greatly reduce the head impact burden and brain injury risk of youth football players.