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The sport of ice hockey contains the highest incident of concussion and head injury per participant in all of sports (Kendall et al., 2012). In Canada, for example, 3.78% of sport-related emergency room visits in a year related to head injuries experienced by people while playing ice hockey. Among these head injuries, concussions seemed to be the most prevalent type of head injury (Wennberg & Tator, 2003). A concussion or mild traumatic brain injury (mTBI) is “an alteration in brain function, or evidence of brain pathology, caused by an external force” (Menon, Schwab, Wright, & Maas, 2010, p.1637).
The elevated incident of concussions in the sport of ice hockey relates to the high level of impact forces to the head experienced by individuals while playing the sport (Post, Oeur, Hoshizaki, & Gilchrist, 2011; Wennberg & Tator, 2003). These impacts forces result in either linear or rotational accelerations affecting the brain matter and consequently producing concussions (Meaney & Smith, 2011). Linear acceleration refers to a vector quantity representing the rate of change of linear velocity over time measured in units of g (Gimbel & Hoshizaki, 2008). A g unit signifies a multiple of the acceleration due to gravity (Post, Oeur, Hoshizaki, & Gilchrist, 2011). Angular acceleration, on the other hand, refers to a vector quantity representing the change in angular velocity over time measured in radians per second squared (McLean & Anderson, 1997).
Peak linear acceleration represents the most frequent measure used to assess head injuries and helmet performance in the sport of ice hockey. The magnitude of the linear accelerations seems to indicate the severity of the head injury due to the impact (Gurdjian et al., 1968). The magnitude of the rotational accelerations, on the other hand, seems to be more associated with high levels of tissue strain and brain damage (King, Yang, Zhang, & Hadry, 2003).