Injuries tendency during fall league match in the Japanese Chushikoku area collegiate American Football league match, past 7 seasons (2012 - 2018).

Objective: American Football (AF) is a sport with intense physical contact, and there are many injuries. According to the surveys on injuries in collegiate AF in Japan, ligament injuries were the most frequent (37 - 39%). These studies were conducted in the Kanto or Kansai leagues, which have sufficient players. However, no surveys on injuries has been conducted in leagues with a small number of players, such as in the Chushikoku league. Therefore, this study aimed to investigate the occurrence of injury in the Chushikoku Collegiate AF league. Methods: The survey period spanned 103 games played over 7 seasons. The survey subjects had described in the injury report of the Japan AF Association. The injury report was described when a "timeout for the injured" was called by the referee. The survey items included the player's position, injury type, injury location, the quarter (Q) during which the injury occurred, and the number of injuries per game. Results: The total number of injuries was 424. The number of injuries per games was 4.1 per game. The most frequent type of injury was bruising in 138 cases (32.5%). In addition, there were 114 cases (26.9%) of muscle cramps and 74 cases (17.5%) of ligament injuries. There were 189 cases among offensive players and 235 cases among defensive players. The timing of the injury was the 3Q in 127 cases and 4Q in 183 cases. Overall, 73.1% of injuries occurred late in the game. Conclusion: Previous studies reported the number of injuries for the Kanto Collegiate AF league to be 1.3 per game. In contrast, the number of injuries in Chushikoku league was 4.3 per game, and the prevalence of bruises and muscle cramps was overwhelmingly large. This high number could be due to several factors, such as few players per team (few opportunities for substitution), and the participation of students with lower skills. Clinical implications: The injury rates in the Chushikoku league tended to differ from those of other leagues. [ABSTRACT FROM AUTHOR]