Head impacts in youth national hockey leagues in Slovakia: a retrospective analysis of four seasons.

Traumatic brain injury in contact sports can lead to serious health consequences either immediately or later in the life of injured subjects. The objective of this study was to estimate the incidence of head impacts in the Under 18 (U18) and Under 20 (U20) junior ice-hockey leagues in Slovakia over the seasons 2013/2014-2016/2017 using data from official game statistics. Incidence risks (IR) per 1000 athlete exposures were calculated for the season and stratified by a period of the game, by month, round, and part of the season.