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Abstract
Concussion is prevalent in collision and contact sports and, therefore, an injury of specific interest. Laboratory and epidemiological research in football codes, in which headgear is not mandatory, has demonstrated the limited effectiveness of headgear in preventing concussion. To further understand the biomechanics of concussion and develop effective prevention methods, it was necessary to investigate the dynamics of head impacts in sport. The kinematics from no-injury head impact cases, in elite football codes commonly played in Australia, were estimated using quantitative video measurement methods and rigid body reconstructions. The 13 no-injury head impact cases were collated with 27 previously reconstructed cases of medically-verified concussion. A detailed finite element model of the human head was used to approximate the regional distributions of tissue-level predictors of injury in the brain by simulating the 40 head impact cases. The results were evaluated using logistic regression analysis and it was found that rotational kinematics, in the coronal plane, were significantly associated with concussion. In addition, maximum principal strain and Von Mises stress, in the corpus callosum and thalamus, were found to be significantly associated with concussion. The results suggest that impacts to the temporal region of the head cause coronal rotations, which render injurious stress and strain levels in the brain. The findings support the hypothesis that sports-related concussions mechanistically share biomechanical characteristics with diffuse axonal injury. A review of soft-shell sporting headgear identified opportunities to improve designs and performance standards by applying current biomechanical knowledge and tolerance limits of concussion.