A retrospective, within-player case-crossover investigation of professional women footballers has identified modest increases in match exposure and estimated travel distances during the weeks immediately preceding anterior cruciate ligament injuries compared to identical calendar periods from the preceding competitive season. The analysis evaluated 375 professional players competing across Tier 3 to Tier 5 standards who suffered publicly reported anterior cruciate ligament injuries between 2022 and 2024. Researchers examined individual participation records across 30-day, 60-day, and 90-day pre-injury observation windows, contrasting them against each athlete’s personal baseline from exactly 365 days prior. Across every evaluated timeframe, injured athletes logged statistically greater match minutes, total match appearances, and starting appearances before injury than during the matched non-injury control window. However, the observed between-season differences were accompanied by small to negligible effect sizes and extensive individual variation, demonstrating that pre-injury match participation and travel distance serve as contextual risk markers rather than direct, independent causes of ligament rupture.
Anterior cruciate ligament ruptures represent one of the most severe medical burdens in modern professional association football, carrying prolonged recovery timelines that account for roughly 28 percent of total lost playing time and an average competitive absence of 292 days. Beyond the immediate disruption of time loss, sustaining an anterior cruciate ligament tear elevates the subsequent risk of further knee joint injury by two- to four-fold, frequently produces persistent deficits in physical strength and skill performance, and elevates long-term vulnerability to post-traumatic knee osteoarthritis. In many instances, the severity of the damage culminates in premature athletic retirement. These career consequences remain especially pronounced throughout elite women’s football, where reported injury incidence rates run two to three times higher than those recorded among male professional cohorts, while post-surgical return-to-play metrics remain comparatively compromised.
Medical and sports science literature describes anterior cruciate ligament injury aetiology as a complex, multifactorial phenomenon resulting from continuous interactions between non-modifiable intrinsic traits and extrinsic environmental stressors. Intrinsic influences encompass past injury history, specific anatomical and physiological adaptations, chronological age, and sex-related biological profiles. Because such internal characteristics cannot be actively altered during competitive seasons, scientific attention has focused increasingly on modifiable extrinsic elements, particularly competition scheduling demands, accumulated travel volumes, and physical fatigue. While elevated competitive loading and frequent travel schedules have been proposed to compromise neuromuscular control and tissue resilience during rapid cutting maneuvers, empirical investigations into exposure profiles in women’s football have historically been scarce, relying primarily on small cohorts or between-player comparisons that fail to control for personal physical differences.
To overcome the analytical challenges posed by athlete heterogeneity, the research team implemented a retrospective within-player case-crossover methodology that allowed each injured footballer to serve as her own comparator across consecutive competitive seasons. From an initial identification pool of 541 professional players with publicly verified anterior cruciate ligament ruptures occurring between January 2022 and December 2024, paired longitudinal records were secured for 375 athletes with a mean chronological age of 24.3 years. Each subject met the criteria for Tier 3, Tier 4, or Tier 5 competitive levels under the modified McKay classification structure, representing highly trained, elite international, and world-class performers. Of the recorded injury events with detailed contextual descriptions, 233 ruptures occurred during competitive match fixtures, 78 occurred during team training sessions, and 64 remained unclassified due to limited media documentation, while 11 players sustained re-injuries during the surveillance timeframe.
Player exposure data were gathered through validated media-based surveillance protocols relying primarily on verified records from SoccerDonna alongside secondary cross-referencing against Sofascore. Researchers catalogued competitive formats across domestic leagues, domestic cups, international club tournaments, and national team fixtures, alongside starting selections and minutes on the pitch. Across the dataset, domestic league fixtures comprised the vast majority of match involvement, representing 71.3 percent of matches during injury campaigns and 69.1 percent during control campaigns. Home and away match distributions remained balanced across observation periods at approximately 49 percent home matches and 51 percent away matches. The authors noted that while match minutes and starting appearances represent reliable pragmatic proxies for external match-related workload, the publicly available metrics did not capture internal physiological strain, training sessions, movement velocities, wellness, or direct sleep duration.
Travel exposure was quantified across the 30 days preceding each anterior cruciate ligament injury using the Haversine mathematical formula to determine geographical displacements between home club venues and away competition destinations. Round-trip distances were calculated for away club fixtures, home club fixtures received an assigned value of zero kilometres, and national team departures were calculated from the athlete’s home stadium to the national match venue. For injuries sustained during away fixtures, travel was computed as a one-way displacement. Travel estimates were verified against the FIFPRO women’s workload monitoring tool across seventeen validation cases, exhibiting near-perfect concordance with an intraclass correlation coefficient ranging between 0.99 and 1.00. Time zone crossings were tracked alongside cumulative travel distance, providing indirect indicators of itinerary logistical demands without recording exact flight paths, layovers, or direct ground transport durations.
Statistical evaluation revealed consistent, statistically significant increases in competitive exposure across all analyzed observation intervals, although the absolute differences remained modest. At the 30-day pre-injury threshold, players averaged 34 additional match minutes, 0.8 more appearances, and 0.7 additional starts during their injury seasons relative to their personal baseline from the previous year. Over the 60-day window, these comparative increments expanded to 54.2 additional match minutes, 1.0 more appearance, and 1.0 additional start. By 90 days, injured footballers logged an average excess of 67.6 minutes, 1.2 appearances, and 1.1 starting selections. Across all three observation windows, these exposure differences achieved statistical significance at p < 0.001, though the accompanying Cohen’s d effect sizes ranged narrowly from 0.212 to 0.370, confirming that the magnitude of overall difference was small.
Examinations of match congestion indicators provided a notable contrast with previously published literature that had linked ligament trauma directly to compressed fixture schedules. Within the analyzed cohort, fixtures separated by fewer than five days of recovery appeared slightly more often during the 60-day and 90-day pre-injury periods, averaging differences of 0.3 and 0.4 matches respectively, with negligible effect sizes of d = 0.128 and d = 0.121. Furthermore, metrics tracking matches separated by fewer than three days of rest, unused substitute appearances on team benches, and total scheduled rest days exhibited no statistically significant differences between the injury season and the preceding control period. These findings indicate that absolute accumulated match exposure may distinguish injury windows more reliably than short-term fixture congestion markers, even though the practical clinical relevance of 34 extra minutes over a month remains uncertain.
Geographical movement calculations during the 30 days preceding anterior cruciate ligament ruptures demonstrated an average estimated travel distance of 2724 ± 4821 kilometres in the injury season compared to 2194 ± 4625 kilometres across the matched control period. Although this difference proved statistically significant under Wilcoxon signed-rank testing (V = 22,184, p < 0.001), the substantial variance and broad interquartile range yielded a negligible Cohen’s d effect size of 0.106. The number of time zone crossings showed no significant seasonal variation, averaging 1.2 ± 2.9 crossings prior to injury versus 1.0 ± 3.1 in the control period. In subgroup comparisons, match-related injuries accounted for an average excess of 97 match minutes over 90 days compared to control periods, and players transitioning between club teams accumulated an excess of 76 minutes, whereas training-related injuries showed no statistically significant difference in accumulated minutes.
Bivariate correlation testing established that excess travel distance was moderately associated with excess match minutes (ρ = 0.399, p < 0.001) and more strongly associated with excess match appearances (ρ = 0.556, p < 0.001), demonstrating that physical match participation and long-distance travel frequently coincide in professional football schedules. In multivariable mixed-effects logistic regression models, zero travel during the 30-day pre-injury window was associated with significantly lower odds of an observation belonging to the injury season compared to experiencing any travel (odds ratio 0.43 in the minutes model, odds ratio 0.53 in the appearances model). Conversely, continuous match minutes and appearances did not maintain independent statistical significance within the regression frameworks once travel status was accounted for, suggesting that travel may serve as a proxy for complex clusters of athletic and logistical demands.
Descriptive mapping across competitive tiers highlighted that concurrent increases in both match exposure and estimated travel distance were especially concentrated among specific athlete subgroups, notably players advancing from Tier 3 to Tier 4 domestic and international levels, alongside established Tier 5 world-class athletes. Progression toward higher competitive tiers routinely involves increased competition frequency, entry into multi-stage domestic and continental tournaments, and expanded national team obligations. The authors theorized that rapid escalations in competitive and travel stress could potentially induce transient reductions in neuromuscular readiness, rapid force development, and dynamic movement control during demanding decelerations or cutting actions. However, the researchers emphasized that such physiological mechanisms remain speculative within the scope of observational data and require verification through prospective testing.
The study authors highlighted several essential methodological limitations that preclude drawing direct causal conclusions from these observational results. The dataset relied on publicly reported injury notifications and lacked an uninjured comparison cohort, meaning the findings describe contextual differences within injured individuals rather than absolute injury probability across the wider playing population. Public sources did not consistently differentiate between primary ligament tears, ipsilateral graft failures, or contralateral ruptures, nor did they provide information on contact versus non-contact injury mechanisms, training volumes, or internal physiological strain. Furthermore, travel metrics derived from Haversine calculations represented direct geographical displacements between stadiums rather than actual flight connections, road transit times, or sleep disruptions, reinforcing that match exposure and travel distance should be interpreted strictly as hypothesis-generating contextual markers rather than deterministic predictive thresholds.
Subject of Research: Pre-injury match exposure and estimated travel distance in professional women’s football
Article Title: Match Exposure and Estimated Travel Before ACL Injury in Professional Women’s Football: An Exploratory Within-Player Case-Crossover Study
Article References: Hampstead, W., Pappas, E., Whalan, M., Wakefield, B., Crespin, V., & Lovell, R. (2026). Match Exposure and Estimated Travel Before ACL Injury in Professional Women’s Football: An Exploratory Within-Player Case-Crossover Study. Sports Medicine – Open, 12(1), Article 170. https://doi.org/10.1186/s40798-026-01144-4
Image Credits: AI Generated
DOI: 10.1186/s40798-026-01144-4
Keywords: women’s football, anterior cruciate ligament, ACL injury, match exposure, travel demands, sports medicine, case-crossover study, athletic workload, Match, Exposure, Estimated, Travel
