A One-Year Retrospective Study of the Occurrence of Sport-Related Concussions in Japanese University Sports: Characteristics of Athletes with Multiple Occurrences

Background/Objectives: This study aimed to investigate the occurrence of sport-related concussions (SRCs) in Japanese university sports and to identify factors associated with experiencing multiple SRCs within a single season. Methods: Data were collected through a web-based survey conducted from June to October 2022, focusing on injuries sustained between April 2021 and March 2022. Participants were recruited from universities affiliated with the Japan Association for University Athletics and Sport and were required to be actively participating in sports. Results: Overall, 10,978 participants were analyzed; 195 reported SRCs, whereas 10,783 did not. Athletes who reported SRCs were significantly taller and heavier, had a higher body mass index, and included a higher proportion of male athletes than those who did not report SRCs. SRCs were most frequently reported in rugby football, American football, soccer, and lacrosse. Among athletes with SRCs, those with multiple SRCs tended to be taller and were significantly heavier. They also had a significantly higher proportion of severe first SRCs during the season. Conclusions: SRCs were most frequently reported in rugby football, American football, soccer, and lacrosse, and greater severity of the initial SRC in a season was associated with multiple SRC occurrence. These findings should be interpreted with caution because SRCs were self-reported and not clinically verified, mild cases may have been underreported, and time-loss-based severity may not reflect clinical severity.