Kevin M. Guskiewicz, Jason P. Mihalik 27-Mar-2014 Exerc Sport Sci Rev. 2011;39(1):4-11. 
Biomechanics of Sport Concussion: Quest for the Elusive Injury Threshold Kevin M. Guskiewicz, Jason P. Mihalik Disclosures Exerc Sport Sci Rev. 2011;39(1):4-11. We hypothesize that within the spectrum of concussion or mTBI, the biomechanical threshold for sustaining the injury is not only elusive, but impact severity (measured in acceleration/deceleration) may be clinically irrelevant. This review aims to collate findings from our recently conducted studies investigating biomechanical relationships with various factors such as playing position, types of play, concussive versus subconcussive impacts, location of impacts, and clinical measures of concussion. The effects of impact management materials in ice hockey helmets on head injury criteria P Rousseau*, A Post, and T B Hoshizaki Neurotrauma Impact Science Laboratory, Department of Human Kinetics, University of Ottawa, Ottawa, Ontario, Canada The manuscript was received on 1 December 2008 and was accepted after revision for publication on 24 June 2009. DOI: 10.1243/17543371JSET36 Abstract: The objective of this study was to compare the capacity of vinyl nitrile and expanded polypropylene, two materials commonly used in ice hockey helmets, to reduce the peak linear acceleration, peak angular acceleration, and head injury criterion values during a direct impact to a hybrid III headform. Six different ice hockey helmets were tested using a pneumatic linear impactor at velocities similar to those in hockey. The results showed that helmets using expanded polypropylene foam liners are significantly better at reducing linear acceleration; however, helmets using vinyl nitrile foam liners are significantly better at reducing angular acceleration. Furthermore, the impact location influenced the performance of the liner.