Video analysis of high-magnitude head impacts in men's collegiate lacrosse.

Background/aim: Lacrosse is one of the fastest growing sports in the USA. Efforts to minimise head injuries focus on promoting safe play through player and coach education, rules enforcement and use of effective protective equipment. The study aims to determine event characteristics of high-magnitude head impacts in men's collegiate lacrosse competitions through video analysis.

Methods: Seventeen Division I men's collegiate lacrosse players wore instrumented helmets that collected biomechanical measures of head impacts. During 15 competitions, the magnitude of linear acceleration, rotational velocity and helmet impact location were recorded. Impacts with linear accelerations above a 70 g threshold were correlated with video to confirm impact location and to determine event characteristics-source of impact and player activity at the time of impact.

Results: A total of 122 high-magnitude impacts were reviewed on video. Player-to-player contact (n=94, 77.0%) was the most common impact mechanism, followed by stick-to-player contact (n=11, 9.0%). Impacts occurred most often when the athlete was delivering a body check (n=39, 32.0%), fighting for loose ball possession (n=35, 28.7%) or attacking the goal (n=35, 28.7%). The most frequent impact locations were the front of the helmet (n=46, 37.8%) and the left side of the helmet (n=26, 21.3%).

Conclusions: In men's collegiate lacrosse games, the majority of high-magnitude head impacts resulted from player-to-player contact when the sensored athlete did not have possession of the ball. Video analysis provides the game context for head impact mechanisms, which is critical to developing sport-specific injury prevention strategies.