Mechanisms causing NHL concussion.

<p>The causes of NHL concussion or suspected concussion were documented for the subset of injuries occurring during the 10 randomly selected weeks for all 3 seasons. The proportion of injuries within each season caused by each mechanism is shown, with the number of injuries above each bar. Unintentional actions included tripping and colliding with a teammate. The rates of each mechanism remained constant over the seasons tested (p>0.05 for all).