Injury Incidence in Professional Football Is Highest During Mid- and Late-Season: A Three-Season Retrospective Cohort Study.

Background: Injuries are a major concern in professional football because they may reduce player availability and affect team performance. Injury risk may vary across different phases of the season in relation to changes in training and competition demands, recovery, and cumulative workload. Objectives: To describe the epidemiology of injuries in a professional football team over three consecutive seasons and to evaluate seasonal variations in injury characteristics and injury-related time-loss. Methods: This retrospective study analyzed 260 time-loss injuries sustained by 78 of 96 registered male first-team players (mean age 27.0 ± 4.5 years) from a professional football club in Türkiye over three consecutive seasons (2022-2023 to 2024-2025). Total team exposure was 33,609 player-hours (2409 match player-hours and 31,200 training player-hours). Injuries were classified according to injury setting, seasonal period, anatomical location, injury type, and injury-related time-loss. Exploratory generalized estimating equations (GEE) analysis accounted for repeated injuries within players. Results: A total of 260 injuries were recorded; 62.3% occurred during training and 37.7% during matches. The overall injury incidence was 7.7 per 1000 player-hours (95% CI, 6.8-8.7), with rates of 40.7 per 1000 match player-hours (95% CI, 33.0-49.6) and 5.2 per 1000 training player-hours (95% CI, 4.4-6.1). The groin-thigh-lower-leg region (52.7%) and the thigh (25.4%) were the most frequently affected anatomical sites, while muscle injuries accounted for 43.5% of all injuries. Estimated injury incidence was highest during the mid- and late-season (9.29 and 9.12 per 1000 player-hours, respectively) and lowest during the preparation period (2.55 per 1000 player-hours). Exploratory GEE analysis showed significant differences in injury counts across seasonal periods (Wald χ2 = 41.35, p < 0.001). Compared with the late season, injury incidence was lower during the preparation period (IRR 0.17, 95% CI 0.09-0.33; p < 0.001), whereas no significant differences were observed for the early or mid-season. Conclusions: Injury incidence was lowest during the preparation period and highest during the competitive season. Because exposure estimates were based on team-level rather than individual player-level data, these findings should be interpreted cautiously. Prospective multicentre studies with individual exposure data are needed.