American society of biomechanics journal of biomechanics award 2019: Circumstances of head impacts in men's university ice hockey

This observational study examined the circumstances of head impacts in men's university ice hockey. Video footage was collected of 449 head impacts experienced by 37 players over 33 games. Videos were analyzed using a reliable, structured questionnaire to classify: playing zone, location on ice, puck possession, direction of gaze, object striking the head, location of head impact, trajectory of colliding players, and penalties. Generalized Linear Models were used to compare response categories for the proportion of players experiencing at least one head impact, and the number of head impacts per player. The majority of events resulting in head impact involved contact with another player (93%). Head impacts occurred most often to players who did not have puck possession, who were checked along the boards in their offensive zone. Players were just as likely to experience head impact with an environmental object, as with an opposing player's body part. Glass-to-head impacts represented 30% of cases, four times as common as board-to-head impacts. Hand-to-head impacts accounted for 23% of cases, twice as common as shoulder- or elbow-to-head impacts. In 27% of events, there were two or more successive impacts to the head (e.g., contact with shoulder and then boards). Only 16% of head impacts which involved contact with another player resulted in infractions. Our results support the need for additional research on the benefits of stricter rule enforcement, and modifications to the stiffness of glass and padding of gloves, for reducing the frequency and severity of head impacts in ice hockey.