Hockey helmet

A hockey helmet is worn by players of ice hockey, inline hockey, and bandy to help protect the head from potential injury when hit by the puck, sticks, skates, boards, other players, or the ice. The shell of a hockey helmet is generally made of a substance called vinyl nitrile that disperses force from the point of contact, while the liner may be made of either vinyl nitrile foam, expanded polypropylene foam, or other material to absorb the energy, to reduce the chances of concussion.^[1] Hockey helmets grip the head from inside by cupping the back of head, or the occipital protuberance. Helmet manufacturers will have a chart that relates their helmet sizes to head measurements. On older models, the helmet size is adjusted by loosening the screws on the side to slide the front portion forward or back.

^ Rousseau, P.; Post, A.; Hoshizaki, T. B. (2009). "The effects of impact management material in ice hockey helmets on head injury criteria". Proceedings of the Institution of Mechanical Engineers, Part P: Journal of Sports Engineering and Technology. 223 (4): 159–65. doi:10.1243/17543371JSET36. ISSN 1754-3371. S2CID 137153670.

[1] Rousseau, P.; Post, A.; Hoshizaki, T. B. (2009). "The effects of impact management material in ice hockey helmets on head injury criteria". Proceedings of the Institution of Mechanical Engineers, Part P: Journal of Sports Engineering and Technology. 223 (4): 159–65. doi:10.1243/17543371JSET36. ISSN 1754-3371. S2CID 137153670.

[1]