Increasing Substitutions in European Football Is Associated With Decreased Injury Rates Among Elite Athletes.

Background: In the 2019/2020 football season, an increase from three to five substitutions was implemented in European football to help players manage a congested match calendar following lockdown due to the COVID-19 pandemic. In this study, we aimed to determine injury rates before and after implementation of five substitutions. Secondary objectives included characteristics and duration of injury and associated risk factors.

Materials and methods: A retrospective review of players injured while playing in the first division of the Spanish professional football league (La-Liga) during the 2017/2018, 2018/2019, 2022/2023, and 2023/2024 seasons were identified from an online database, Transfermarkt. Injury- and player-related characteristics, as well as game play before and after the implementation of five substitutions, were studied. Multivariate regression models were used to assess complications, adjusting for age, minutes played, and appearances.

Results: The overall incidence during the study period was 0.76 injuries per player-season. A total of 1,268 injuries were reported prior to the rule change with an incidence of 0.94 injuries per player-season compared to 711 reported injuries with an incidence of 0.57 injuries per player-season after. There were significantly decreased odds of multiple injuries (odds ratio [OR]: 0.68; 95% CI [0.56, 0.82]; P<0.001) and muscle injuries (OR: 0.72; 95% CI [0.59, 0.87]; P<0.001) after the increase in substitutions.

Conclusion: Implementation of five substitutions was associated with significantly decreased injury rates in LaLiga. Additionally, players had significantly lower odds of sustaining multiple injuries and muscle injuries. [Orthopedics. 202x;4x(x):xx-xx.].