concussions, or mild traumatic brain injuries (mtbi), occur due to an impact on the head and are the most common type of brain injury for goaltenders in the sport of ice hockey. the two main techniques used to mitigate concussion risk for ice hockey goaltenders include improving the impact absorption capabilities of the goaltender helmets and increasing the athlete’s cervical muscle strength. based on these two strategies, this study examined the effect of thermoplastic polyurethane (tpu) as a goaltender helmet liner material to mitigate concussion risk for individuals with different neck strength levels during simulated horizontal head collisions. to address the purpose of this study, static testing was conducted to examine the material properties of the goaltender helmet liners, which was then used to identify the best tpu liner design that improved the performance of the goaltender helmet technology. one particular tpu liner design was found to weigh 2.7 times more on average than the standard liner; however, it was capable of statically absorbing 10.8 times more energy per kilogram than the standard liner. the researcher selected this tpu design and used it in repeated impact testing to further gauge the performance of the tpu and standard liner materials compared to a bare head without liner protection. repeated dynamic impact trials revealed that the tpu liner mitigated impacts similarly to the standard liner, providing evidence of the tpu effectiveness as a possible helmet liner. [...]