Official match time underestimates injury incidence in football and beach soccer compared with futsal

Accurate determination of injury incidence and burden is essential for effective prevention [1]. Misjudging the problem risks leading to ineffective or unnecessary measures [13]. Standardized reporting of injuries using incidence and burden rates is critical for valid cross-sport comparisons [12]. The incidence rate reflects injuries per hours of exposure and the burden rate reflects absence days per hours of exposure [1, 12]. Official match time refers to the match duration according to the rules of the game: 90 min for association football (hereafter referred to as football), 40 minutes for futsal, and 36 min for beach soccer [3-5]. Total playing time represents the actual duration from the initial to the final whistle, including stoppage time (if applicable) [5]. Effective playing time refers to the duration when the ball is in play [5]. In football, effective playing time is approximately 55%–60% of the official match time [2]. In futsal, official match time is equal to the effective playing time because the clock stops whenever the ball is out of play [4]. In beach soccer, mixed timing rules mean that official match time does not fully reflect total or effective play [3]. The International Olympic Committee (IOC) football-specific consensus recommends using official match time (90 min) for football [12]. However, it suggests that futsal and beach soccer may adopt certain relevant aspects of the football consensus until their own guidelines are developed [12]. While the definitions of injuries in the IOC consensus are largely transferable to futsal and beach soccer, the same is not true for exposure time and using official time across all variants creates inaccurate comparisons [6-9]. To elaborate this critical issue, that is, to provide an example and rough estimate of total/effective playing times, final matches of the FIFA Men's World Cup 2022 (Football), FIFA Futsal World Cup 2021, and FIFA Beach Soccer World Cup 2021 were analyzed by two investigators independently. A single event during a match was defined as any occurrence that caused the ball to go out of play (e.g., throw-in, goal kick). Simultaneous or overlapping occurrences (e.g., foul and substitution) were coded as multiple events. A datasheet was created to record each event (e.g., throw-in, goal kick), its duration (in seconds), and whether the clock was stopped (applicable only to beach soccer). Inter-rater reliability was excellent, with Cohen's Kappa ≥ 0.97. We identified 101 events in football, 211 in futsal and 103 in beach soccer. The frequency, duration, and total time per event are presented in Supporting Information S1: File 1. The ratio of official match time/effective playing time was 1.65 for football, 1 for futsal and 1.28 for beach soccer (Table 1). Studies on injury in futsal and beach soccer often rely on the official match time [6-9], following IOC recommendations [12]. Our preliminary findings show that this practice underestimates injury incidence by 65% in football and by 28% in beach soccer—as compared with futsal. Previous meta-analyses estimate match injury incidence as 36/1000 h in football and 44.9/1000 h in futsal [10, 11]. Adjusting our ratios (multiplying football injury rates by 1.65), injury incidence rate in football increases the rate to 59.4/1000 h, surpassing futsal. Needless to say, this discussion can also be extrapolated for performance-related outcomes (e.g., total distance covered or sprint activities per minute). It should be emphasized that these ratios are rough estimates derived from single matches in each sport, provided solely to illustrate potential discrepancies and to highlight the need for further research. More extensive analysis should be derived from robust conversion factors, considering, player position, pitch size, number of players, match context, and relative team strength. Recognizing and correcting these differences is crucial for reliable injury surveillance. Future research should establish sport-specific conversion factors for exposure time and develop futsal- and beach soccer–specific extensions of the IOC consensus statement. These extensions should integrate harmonized core definitions to allow cross-sport comparisons, also capturing unique features of each discipline, such as the small-sided format of futsal and the high head injury incidence, frequent bicycle kicks, and barefoot play in beach soccer. However, tailored approaches may complicate comparability through differing registration methods. Therefore, overarching IOC guidelines remain essential. A dual framework, harmonized core definitions complemented by sport-specific refinements, would provide the best balance between comparability and sport-specific accuracy. In conclusion, relying solely on official match time as exposure in football, futsal, and beach soccer produces biased incidence estimates due to differing timekeeping rules. Standardizing definitions and sport-specific consensus statements are essential steps toward improving the accuracy of injury surveillance and enhancing preventive strategies. Yavuz Lima: Conception and design, data acquisition, writing, proofreading. Levent Özçakar: Internal review, data analysis, proofreading. Ogün Köyağasıoğlu: Internal review, data acquisition, proofreading. Benjamin Clarsen: Internal review, data analysis, supervision, proofreading. The authors have nothing to report. The authors declare no conflicts of interest. The authors have nothing to report. The data that support the findings of this study are available from the corresponding author upon reasonable request. Please note: The publisher is not responsible for the content or functionality of any supporting information supplied by the authors. Any queries (other than missing content) should be directed to the corresponding author for the article.