In youth hockey the act of bodychecking is used to separate the opponent from possession of the puck by contacting the body. In one form or another bodychecking has been an integral part of hockey, especially competitive hockey. Bodychecking is associated with a high risk for concussion symptoms with a number of studies reporting a significant decrease in concussion symptom presentation when bodychecking is removed from the game (Black et al., 2016). To decrease the incidence of concussion symptom presentation and maintain body checking in the game, some leagues have introduced modified body contact rules. This study compared the brain trauma profiles, characterized by frequency and magnitude, of players playing with modified body contact rules to a standard bodychecking hockey league. U15 AAA adhered to standard bodychecking, while M15 minor only allowed shoulder-to-shoulder contact while keeping sticks on the ice and travelling in the same direction along the boards.

16 U15 AAA and 16 M15 minor hockey games were analyzed documenting head impacts, and head impact conditions that were reconstructed to examine the differences by comparing frequency and magnitudes of head impact events. There were 76 and 101 impacts in AAA and M15 minor, respectively. Most common events in AAA were head-to-glass, shoulder, and other;​ and in M15 minor were head-to-shoulder, head, and other. Magnitudes were grouped into very low, low, medium, high, and very high. The only magnitude levels that were significantly different when comparing total head impacts were more very low magnitude head impacts in M15 minor. Most common frequencies of magnitude levels for events in AAA were low glass, and in M15 minor were very low head, and low shoulder events.

Changing the body contact rules increased the frequency of very low magnitude events and did not change the frequency of individual events between the medium and very high magnitude events. The low magnitude displayed a shift from head-to-glass to shoulder-to-head events when body contact rules were modified. These findings suggest that modifying body contact rules can result in differences in the frequencies and magnitudes of head impacts in U15 ice hockey. Changing body contact rules resulted in changes of most common events, though the frequency of magnitudes of brain trauma did not decrease with modified contact. It is important to understand the risks associated with the frequencies of events and magnitudes in both divisions.