The Acceleration-Axonal Strain Relationship and mTBI: Future Directions for Head Protection Available to Purchase

The primary determinant of helmet suitability in performance standards and certification programs is the head-form acceleration (peak acceleration <275 to 300 g) obtained in the drop tests. This has led to ice hockey helmets that have been very successful in reducing the risk of focal (localized) head injuries. Parallel to this development has been a concomitant increase in the amount and severity of checking about the head that has led to a substantial rise in mTBI at all levels of hockey. While this may be regarded as a behavioral issue, calling for improved player respect, rules enforcement, etc., there are some who believe that mTBI risk reduction can be achieved via helmets. The cause of mTBI is axonal shear strain precipitated by rotational acceleration of the brain. While recent research has indicated that the concussion state is precipitated by a strain of some 2 to 5% and beyond, the level of acceleration needed to produce this amount of strain is unknown. This paper will explore the need for establishing an acceleration-axon strain relationship that may eventually be used to develop head protection strategies that are effective in reducing the concussion risk in hockey.