Determinants Of Head Impact Exposure In Youth Football

Abstract

Concussions are on the minds of many football players, parents and coaches; but attention has increased toward the potentially damaging effects of repetitive, subconcussive head impacts, particularly among youth football players. Advocates of the sport are looking for ways to improve player safety and reduce the potential risk of long-term brain abnormalities. PURPOSE: To identify intrinsic and extrinsic characteristics of play associated with head impact exposure in youth football. METHODS: Head impacts from one youth football team (7th & 8th grade) were measured during every practice and game during the 2018 & 2019 football seasons via a sideline head impact telemetry system and subsequently evaluated using video collected during each session. Each verified head impact was scored using a validated rubric consisting of up to 12 discrete characteristics of play (5 intrinsic, 7 extrinsic). The mean, median and 95th percentile linear acceleration (LA) was calculated for each play characteristic. RESULTS: Over two seasons, 1202 practice (median LA: 19.90 g) and 1571 game (median LA: 21.00 g) head impacts (2773 total) were examined. The “kickoff” (n = 95 impacts; 6% of all game impacts) had the highest 95th percentile LA (69.89 g) among all game play types (e.g., “run”, “pass”, “punt”, etc.). Impacts that occurred “outside the hash marks” (61.75 g) and in the “redzone” (59.40 g) had the highest 95th percentile LA rankings among horizontal and vertical field positions, respectively. When players did not anticipate being hit (n = 53; 1.9% of all impacts), head impacts had a 95th percentile LA of 69.52 g, compared to 47.02 g when they anticipated the impact. Head impacts resulting from players’ helmets hitting the ground (95th percentile LA: 72.94 g) accounted for 11.6% of all impacts (n = 323). CONCLUSIONS: These data indicate that certain, modifiable characteristics of play are associated with higher magnitude head impacts in youth football. Additional research is warranted to continue to examine practice and game situations (extrinsic characteristics) that produce higher magnitude head impacts, which could assist football-governing bodies in developing or modifying policy guidelines to help make the game safer. Supported by a grant from The National Operating Committee on Standards for Athletic Equipment (NOCSAE).