Head Impact Exposure of a Youth Football Team over Eight Consecutive Seasons

Med Sci Sports Exerc. 2021 Jul 23. doi: 10.1249/MSS.0000000000002756. Online ahead of print.

Abstract

Despite growing evidence for the potential risk of brain injury due to repetitive, subconcussive head impacts in youth football, a longitudinal assessment of head impact exposure (HIE) in this population is lacking.

Purpose: This study examined HIE of middle school football players over multiple seasons.

Methods: HIE was evaluated in 103 football players (11-14 yr) who participated in a community-based youth tackle football program, up to two years, with the same coaching staff over eight consecutive seasons (2012-2019). HIE was assessed using the Head Impact Telemetry (HIT) System. Median of individual mean head impacts per session (HIPS) and median of individual 50th and 95th percentile head impact magnitudes were compared across seasons.

Results: There were 33,519 head impacts measured throughout the study. Median HIPS for all sessions decreased every year, with a significant reduction from 2012 to 2019 (11.1 vs. 2.3 HIPS; P < 0.05). Median game HIPS were significantly reduced in 2019 compared to 2012-14 (5.00 vs. 16.30-17.75 HIPS; P < 0.05). Median practice HIPS were reduced by 81.3%, while median game HIPS were reduced by 69.3%. Median 50th and 95th percentile linear and rotational acceleration were lower in 2019 compared to some earlier years but remained unchanged during games.

Conclusion: Head impacts incurred by youth football players decreased substantially over eight seasons, with players in the final year sustaining approximately one-fourth the head impacts per session as players experienced during the first year. The most prominent decline occurred in practices, though players also had much fewer head impacts in games. These results suggest that coaches' and/or players' behavior can be modified to greatly reduce the head impact burden in youth football.