The association between Guardian Cap use during practices and sport-related concussion risk in high school American football players

Objective Guardian Caps (GCs) have been widely implemented at all levels of American football participation based on laboratory evidence that they may reduce head impact forces. The purpose of this study was to determine if GC use during practice was associated with a lower risk of sport-related concussion (SRC) during practices and games among high school football players. Methods Data were collected on 2610 athletes from 41 Wisconsin schools that self-selected into GC or Non-GC cohorts. Athletic trainers recorded practice and game exposures and SRCs through the 2023 season. Generalised linear mixed models were built to determine the effect of GC utilisation on SRC rates, accounting for school and player exposures. Results In the total cohort (Non-GC n=1188 (45.5%); GC n=1422 (54.5%)), 180 athletes (6.9%) sustained SRCs. 64 SRCs occurred during practice (GC n=33 (51.6%); Non-GC n=31 (48.4%)). GC use was not associated with a decreased risk of SRC during practice in the univariable analysis (relative risk (RR)=1.04, 95% CI 0.58 to 1.86, p=0.90) or after accounting for previous SRC within the last year (RR 1.01, 95% CI 0.57 to 1.79, p=0.97). No players of either cohort wore GCs during games. There were 116 SRCs sustained during games (GC n=68 (58.6%); Non-GC n=48 (41.4%)). GC use during practice was not associated with the risk of SRC during games in the univariable analysis (RR 1.13, 95% CI 0.72 to 1.78, p=0.60) or after accounting for previous SRC within the last year (RR 1.13, 95% CI 0.71 to 1.78, p=0.61). Conclusion GC use during practice in high school American football players was not associated with a decreased risk of sustaining SRC in practice or games. Data are available upon reasonable request.