Quantifying Head Impacts in Collegiate Lacrosse.

Background: Concussion and repetitive head impact in sports has increased interest and concern for clinicians, scientists, and athletes. Lacrosse is the fastest growing sport in the United States, but the burden of head impact in lacrosse is unknown.

Purpose: The goal of this pilot study was to quantify head impact associated with practicing and playing collegiate lacrosse while subjects were fitted with wearable accelerometers.

Study Design: Descriptive epidemiology study.

Methods: In a single year, a collegiate cohort of 14 women's and 15 men's lacrosse players wore mastoid-patch accelerometers to measure the frequency and severity of head impacts during official practices and games. Average impact severity, mean number of impacts, and cumulative acceleration were evaluated, stratified by sport and event type.

Results: Men's and women's collegiate lacrosse players did not significantly differ in the number of head impacts received during games (11.5 for men vs 9.2 for women) or practices (3.1 vs 3.1). Men's lacrosse players had significantly higher average head acceleration per impact during games compared with women (21.1g vs 14.7g) but not during practices (21.3g vs 18.1g). For both men and women, more impacts occurred during games than during practices (men, 11.5 vs 3.1; women, 9.2 vs 3.1), but impact severity did not significantly differ between events for either sport (men, 21.1g vs 21.3g; women, 14.7g vs 18.1g).

Conclusion: The study data suggest a higher impact burden during games compared with practices, but this effect is driven by the quantity rather than severity of impacts. In contrast, sex-based effects in impact burden are driven by average impact severity rather than quantity. Data collected from larger multisite trials and/or different age groups could be used to inform ongoing debates, including headgear and practice regulations, that might appreciably affect the burden of head impacts in lacrosse.

Clinical Relevance: While most head impacts do not result in a clinical diagnosis of concussion, evidence indicates that subconcussive head impacts may increase susceptibility to concussion and contribute to long-term neurodegeneration.