2024 Scholars' Research Symposium Abstract: Characteristics of Play Associated with Head Impact Severity During Tackling in Youth Football.

Introduction: In the last decade, concussions and subconcussive brain trauma in football and other high impact sports have become of increasing concern. Tackling, in youth football, accounts for a high proportion of head impacts and injuries, including concussions. Thus, minimizing head impact severity during tackling may help in reducing concussion risk and subconcussive brain trauma. However, it is unknown how discrete aspects of play in youth football relate to head impact severity during tackling.

Methods: 25 youth tackle football players (12.9 ± 0.6 yr) wore helmets outfitted with the Head Impact Telemetry (HIT) System during two football seasons (64 practices and 18 games). Measures of head impact severity, including linear acceleration (LA) and rotational acceleration (RA), were collected at each session, along with videography. Videos and HIT System data were cross analyzed using a validated rubric to code each registered head impact based on several pre-identified characteristics of play. Sample distributions of play characteristics were compared using the nonparametric Mann-Whitney U test. Level of significance for all tests was α = 0.05.

Results: There were 1025 head impacts identified for players making a tackle or being tackled. LA of head impacts was significantly greater (p = 0.017) for players making a tackle (n = 614; 21.70 [16.40-30.13] g) than players being tackled (n = 411; 20.50 [15.90-30.10] g). In comparing head impacts on tackles, LA was significantly greater (p = 0.010) for special teams (n = 39; 29.10 [21.40-39.70] g) over defense (n = 348; 22.50 [16.90-31.55] g), and RA was significantly greater (p = 0.003) for special teams (n = 39; 2241 [1223-3175] rad ∙ sec-1) over defense (n = 348; RA = 1618 [1004-2293] rad ∙ sec-1). While being tackled, player-to-ground head impacts LA values (n = 102; 25.85 [18.65-35.13] g) were significantly greater (p less than 0.001) than player-to-player head impacts (n = 308; 19.75 [14.95-26.68] g), and player-to-ground head impacts RA values (n = 102; 1687 [1108-2690] rad ∙ sec-1) were significantly greater (p less than 0.001) than player-to-player head impacts (n = 308; 1313 [906-1832] rad ∙ sec-1).

Conclusions: There are certain characteristics of play in youth football that were associated with higher magnitude head impacts during tackling, including being the tackler, special teams plays and head contact to the ground while being tackled. These characteristics of play may serve as targets for mitigation efforts aimed at reducing head impact severity in youth football.