OBJECTIVE: To determine the effects of infraction and noninfraction collisions sustained during participation in youth ice hockey on biomechanical measures of head impact severity. DESIGN: Prospective cohort study.
SETTING: Bantam League ice hockey games during 1 season. PARTICIPANTS: A convenience sample of 16 male Bantam AAA-level ice hockey players (including 1 goaltender who was removed from the analyses; mean age, 14 y; 9 forwards and 6 defensemen) was studied.
ASSESSMENT OF RISK FACTORS: Body collisions that occurred during matches were captured on video footage. Recording followed the movement of the puck and was continuous and time-stamped. Collisions outside the view of the camera were excluded from the analysis. Collisions were subdivided into rule infractions or not, the type of infraction (boarding/charging, checking from behind, elbowing, head contact, and high sticking), and whether the player was the striker or was struck. Collisions were evaluated from the video by the principal investigator, and 4 months later, a subset was reevaluated (88% agreement in evaluation of the presence and type of infraction).
MAIN OUTCOME MEASURES: The main outcome measure was head impact severity during collisions, measured as linear acceleration >10g of the center of gravity of the head, rotational head acceleration (rad·s), and Head Impact Technology severity profile (HITsp; Simbex, Lebanon, New Hampshire), which is a composite of linear and rotational accelerations and impact duration and location. These measurements were picked up and transmitted by means of the HIT system that was contained in the players' close fitting helmets, which were adapted for the purpose. They were synchronized to the video record of collisions. MAIN
RESULTS: Of 665 body collisions, 82.7% were deemed legal, and 17.3% were deemed infractions. Linear accelerations and HITsp were greater during collisions involving infractions than during noninfraction collisions (P = 0.012 and P = 0.021, respectively), but rotational accelerations did not differ for infractions and legal collisions (P = 0.142). Elbowing, intentional head contact, and high-sticking infractions accounted for 11% of collisions and, compared with all noninfractions, produced greater linear acceleration (P = 0.005) and HITsp (P = 0.01) but not greater rotational acceleration (P = 0.059). Boarding/charging infractions and checking from behind did not result in significantly greater linear acceleration, rotational acceleration, or HITsp than all noninfraction collisions (P ≥ 0.103 for each category). Players who were struck from behind sustained lower rotational head accelerations than those who did the striking, but there were no other differences between players who were struck and the strikers in elbowing, head contact, high-sticking, boarding, or charging infractions.
CONCLUSIONS: Although collisions involving infractions were a small proportion of Bantam-level ice hockey collisions, they did result in greater head impact severity on some biomechanical measures.