Breaking point: Fatigue and behavioral edges in global football tournaments

The global football calendar has become increasingly congested, with elite players now participating in a growing number of domestic, continental, and international competitions with minimal recovery time. While the commercial and institutional motivation for this expansion is evident (e.g. greater revenue, broadcasting rights, and global audience engagement), the physiological and qualitative costs of this trend are becoming increasingly evident.

These concerns are increasingly echoed by practitioners. For instance, commenting on his team's season in 2026, Antonio Conte, coach of Napoli and the reigning Italian champions at the time of the statement, argued that “there is simply too much football being played, players are being worn down” explicitly linking fixture congestion to player exhaustion and commercial pressures. The statement, made during a press conference and reported by Il Giornale (31 January 2026), captures a widespread sentiment among elite coaches. While anecdotal in nature, such remarks motivate the need for a systematic, long-run empirical assessment of workload accumulation and its consequences for international competition.

Recent analyses have identified that contemporary footballers may engage in up to 80 competitive matches within a calendar year, often with fewer than 72 h of recovery between fixtures (Carling et al., 2015). This scheduling density has clear physiological implications. Although the total distances run per match remain relatively stable, congested calendars are associated with reductions in high-intensity running, fewer accelerations and decelerations, and the adoption of deliberate pacing strategies to mitigate fatigue (Oliva-Lozano and Muyor, 2022; Jones et al., 2019). These adaptations may compromise overall match intensity, tactical complexity, and, ultimately the quality of the sporting spectacle.

The detrimental effects of fixture congestion are further exacerbated by cumulative fatigue, increased musculoskeletal strain, and impaired neuromuscular function. For example, Gonzàlez-Fernàndez et al. (2025) found that four-match weeks significantly increased fatigue markers and delayed recovery in youth players. Moreover, meta-analyses of professional squads reveal a positive correlation between fixture congestion and injury incidence (Howle et al., 2020). Notably, congested periods are also linked to reduced cognitive functioning, which may negatively affect decision-making and match outcomes (Mohr et al., 2005).

These concerns are not confined to laboratory or biometric analysis. In recent years, high-profile tournaments such as Euro 2024; Copa América 2024 have been criticized for producing lackluster performances, likely exacerbated by overuse and cumulative player fatigue ^[1]. Footballers themselves have begun to voice discontent, warning that an overloaded schedule “is killing the product” and calling for structural reforms led by player associations and unions ^[2]. The 2024–25 season, described as “the longest ever,” has brought these debates to the fore ^[3].

From a cultural standpoint, there is growing concern that the sheer volume of football may paradoxically erode its entertainment value by diminishing scarcity, anticipation, and tactical sharpness ^[4]. Competitive balance, a widely recognized driver of spectator appeal, is generally enhanced by closely contested matches (Fort and Maxcy, 2003). This is consistent with evidence from other sports showing that deeply ingrained playing habits, shaped by specific local rules, can persist and affect performance when the competitive framework changes (Alfano and Capasso, 2020).

From a performance standpoint, the overextension of elite athletes challenges the central promise of professional football: delivering high-quality, physically intense, and emotionally resonant competition. If excessive match frequency undermines physical preparedness and raises injury risk, the long-term appeal of the sport may be compromised. This issue is particularly pressing in light of recent structural changes to the international football calendar, most notably the forthcoming expansion of the FIFA Club World Cup. Since 2025, the tournament features 32 teams and occur quadrennially, a substantial increase in elite-level competitive commitments for players already subjected to demanding seasonal workloads. Moreover, since 2026 also the FIFA World Cup feature 48 teams, expanding its number of participants and hence increasing players' workload globally.

From an economic design perspective, such expansions raise concerns about diminishing marginal returns from additional fixtures and the risk of long-term audience saturation (Szymanski, 2003). Unlike previous tournaments, which involved fewer matches and teams, the restructured World Cup will impose extended travel, exposure to varied climatic conditions, and additional high-stakes fixtures, particularly for players from clubs in the top five European leagues (the English Premier League, La Liga in Spain, the Bundesliga in Germany, Serie A in Italy, and Ligue 1 in France). Consequently, the cumulative burden of regular season play is likely to intensify even further, reinforcing the urgency of understanding the downstream effects on match quality, competitive balance, and the broader dynamics of international football.

The objective of our contribution is twofold: to trace the evolution of player workloads over the past 50 years, and to provide initial empirical insights into how fixture inflation may be associated with the spectacle and sustainability of elite football in an era of continuous global expansion. This article investigates whether there is a threshold beyond which “more football” ceases to enhance the sport's appeal and instead begins to erode its physical, aesthetic, and competitive integrity. To address this question, we compile a historical dataset covering the last 50 years, documenting the cumulative minutes played by the 50 footballers that played the most across seasons (and hence those with the greatest workload). Our primary objective is to offer a descriptive analysis of the evolution of player workloads over time, disaggregated by player role and by league groupings. In particular, we contrast athletes from the top five European leagues with those who are active in other professional leagues, thereby offering empirical evidence on the changing demands in the game.

We complement this analysis with regression models assessing the relationship between cumulative minutes played and the perceived spectacle of international tournaments, including the FIFA World Cup, UEFA European Championship, and CONMEBOL Copa América. Through this empirical strategy, we aim to contribute to the ongoing debate on fixture congestion by situating it within a historical context and by providing quantitative evidence on its potential consequences for the quality of elite football.

The qualitative standard of football matches is widely acknowledged to be the outcome of a complex interplay of multiple interrelated factors. Among these, players' accumulated match time is increasingly recognized to be a salient determinant, particularly in the context of the relentless expansion of modern football calendars. While physical conditioning, tactical coordination, and team structure remain fundamental to performance, the cumulative burden of match exposure has emerged as a significant, and contested, driver of both individual performance and overall match quality (AIC, 2024; Chang et al., 2024).

The existing literature provides mixed evidence. On the one hand, several studies suggest that frequent match participation may consolidate technical fluency and tactical cohesion, especially for attacking players. Chang et al. (2024) find that match frequency is a stronger predictor of offensive productivity than either total minutes played or the number of starting appearances, suggesting that potential rhythm benefits from continual engagement. On the other hand, there is robust evidence linking excessive workload to increased injury risk. The Italian Footballers' Association (AIC, 2024) reports that players with more than 40 appearances per season face a significantly higher probability of muscular and joint injuries, with projections warning that continued calendar expansion may raise unavailability rates by over 50%.

Further evidence comes from age-specific analyses: veteran players over the age of 31 experience the highest injury incidence under heavy workloads (Chang et al., 2024). Conversely, Sal-de-Rellán et al. (2023) show that younger national teams tend to outperform older ones in FIFA World Cups, suggesting a resilience advantage under tournament pressure.

From a physiological standpoint, debate persists as to whether elite players can adapt to dense scheduling. For example, Lago-Peñas et al. (2016) argue that total distance and sprint frequency can be maintained despite fixture congestion. Similarly, Bradley (2024) reports elevated high-intensity running during the 2022 FIFA World Cup. However, these findings must be treated with caution. As Fernández-Cortés et al. (2022) demonstrate, periods of high match density often coincide with tactical conservatism and reduced offensive intensity, likely driven by both psychological fatigue and deliberate load-management strategy.

A related strand of literature examines the relationship between workload and match spectacle, an emerging yet underexplored concept encompassing goal frequency, competitive intensity, and fluidity of play. To our knowledge, no study has directly assessed the impact of cumulative minutes played with a club on the spectacle of international summer tournaments such as the FIFA World Cup, UEFA European Championship, or Copa América. Instead, existing research has tended to focus on related dimensions. For instance, Scoppa (2015) finds that short rest periods (three days or fewer) correlate with improved performance in international tournaments, although this effect appears to have diminished in recent decades. Collet (2013) and Njororai (2014) investigate metrics such as possession, passing patterns, and goal timing, finding limited predictive value for international success and suggesting that late-match goals are frequent but not statistically understood.

Other contributions emphasize the importance of positional and contextual factors. Di Salvo et al. (2007) demonstrate that central and wide midfielders endure significantly higher physical loads than players in other positions, underscoring the need for role-specific workload analyses, a focus the present study adopts. Raya-González et al. (2022) extend this line of inquiry by showing that post-injury reintegration often fails to restore sprint capabilities, potentially compromising tactical continuity and reducing match spectacle.

Despite the expanding body of research on performance and injury metrics, few studies adopt an integrative framework linking club-level workloads to the qualitative dynamics of international football. As Fernández-Cortés et al. (2022) and Sullivan et al. (2014) argue, the sport would benefit from frameworks that unify physical, technical, and psychological indicators under conditions of fixture congestion. This article addresses this gap by documenting long-term trends in playing time across leagues and positions, and by exploring whether player overuse may be associated with diminishing returns in the appeal of international tournaments.

Building upon the descriptive analysis of player workload over time, this study investigates whether accumulated playing time during the regular season is associated with the dynamics of international competitions. Specifically, we examine whether the intensity and frequency of match exposure over the course of the regular season, operationalized as the total minutes played during the regular season, affect the competitive and disciplinary characteristics of major summer tournaments, namely the FIFA World Cup, the UEFA European Championship, and the CONMEBOL Copa América.

The first part of the analysis provides a longitudinal account of the evolution of playing time by role (e.g. defenders, midfielders, forwards, goalkeepers) and by league grouping (the top five European leagues versus all other leagues). This descriptive component maps the distributional patterns of workload among international players, offering a foundation for understanding how modern football's intensified scheduling may manifest unevenly across roles and contexts.

The second part tests a set of empirical hypotheses linking cumulative regular-season minutes to key indicators of match outcomes and style in international tournaments. These indicators, commonly used proxies to illustrate match dynamics, include the total number of goals scored per match, the goal difference, and the incidence of yellow and red cards. Examining these variables allow us to capture both the offensive vibrancy and the physical or emotional intensity that characterize international football contests.

Accordingly, we hypothesize:

Following this introduction, the remainder of the paper is structured as follows. Section 2 describes the dataset, and presents descriptive statistics on the number of minutes played by the 50 most-utilized players each season from 1975–76 to 2023–24. Section 3 outlines the empirical strategy used to examine the relationship between minutes played and the spectacle of international football competitions, while Section 4 discusses the results. Section 5 concludes.

To address our research questions, we compiled an original dataset drawing on multiple sources and covering nearly 50 years of football history (from the 1975/1976 to the 2023/2024 seasons), comprising a total of 4,900 observations. Of these, 2,450 correspond to players from the “Top 5 Leagues” (Premier League, Serie A, Ligue 1, Bundesliga, La Liga), while the remaining 2,450 pertain to players active in other domestic and international competitions (hereafter referred to as “All Leagues”).

A primary data source is Transfermarkt, one of the most widely recognized and comprehensive databases on professional football. The platform's data are compiled and updated through a combination of manual input by registered users, contributions from dedicated editors and data scouts, and subsequent verification by its the editorial team. Although Transfermarkt does not rely on a single proprietary data provider, its community-based collection methodology, supplemented by editorial cross-checking, ensures broad coverage and a level of reliability appropriate for aggregate-level analyses.

Owing to its wide coverage and open structure, Transfermarkt has been increasingly adopted in academic research. Its datasets, encompassing player market valuations, injuries, match performance, and match exposure, have been used in numerous studies across sports economics, analytics, and sports medicine, confirming the platform's importance as a credible data source in empirical football research (e.g. Leventer et al., 2016; Grassi et al., 2020; Hoenig et al., 2022).

For each season, we identified the 50 players with the highest number of minutes played, a criterion designed to ensure comparability across leagues with varying match structures and calendar lengths. Each observation includes demographic variables (name, age, nationality), contextual information (club, league, type of competition), and performance metrics (number of matches played, and total minutes on the pitch). The dataset was carefully cleaned to ensure consistency across seasons, eliminating duplicates and correcting anomalies. By focusing on the 50 players who played the most minutes in a given league group and year, the dataset provides a synthetic yet robust representation of elite player workloads, capturing long-term trends in the intensification of football schedules and enabling a role- and league-specific breakdown of time use across nearly five decades.

The descriptive analysis reveals a sustained increase in the average number of minutes played by top professional footballers over the last 50 years, both in terms of mean and total values. This upward trajectory, observable across both the top five European leagues and the broader group of all professional leagues, underscores the mounting intensity of the global football calendar. Figures 1 to 3 illustrate this trend, showing that while players in the top five leagues generally accumulated significantly fewer minutes per season than their counterparts in other leagues during the 1970s and 1980s, the gap has progressively narrowed. In recent decades, average workloads in elite European competitions have risen substantially, approaching those of players in smaller leagues. Nonetheless, on average players in the “All Leagues” category still record, on average, 300–500 more minutes per season, suggesting lower rates of squad rotation and player turnover. On average, the players who were on the pitch for the most minutes in the top five leagues played 500 min more in 2023–24 than they did in 1975–76, an increase of approximately one-seventh, from an average of 3500 min–4000 min per season. To contextualize, with due acknowledgment of the differences between professions, this is akin to moving from a 40-hour per week to a 45- or 46-hour workweek.

It should also be noted that the seasons between 2020 and 2022 were inevitably influenced by the effects of the COVID-19 pandemic, with compressed calendars, forced interruptions, and rescheduling, which clearly generated some outliers that are visible in the annual playing time data, especially for positions and leagues with less squad depth.

Figure 4 presents playing-time distribution by position, disaggregated by decade and league group. While overall patterns remain broadly stable, the data reveal structural shifts in positional usage consistent with tactical evolution in modern football.

Overall, the positional breakdown of players with the most playing time points to a set of generally stable deployment patterns, yet it also reveals important structural shifts. These shifts mirror broader tactical developments in modern football and underscore the differentiated physical demands placed on players in various roles. Figure 5 summarizes the trends, confirming not only the upward trajectory of average seasonal playing time for all the roles, but also the differences in intensity depending on the tactical role and league context. Collectively, these patterns reinforce the hypothesis of a progressive exposure to physical overload, an issue central to the current debate on the so-called “congested calendar” among clubs, coaching staff and international bodies. Full positional breakdowns are reported in Online Appendix.

Over the last 50 years, players have played an ever-greater number of minutes. But has this rise in regular-season workloads affected international competitions? To empirically assess the relationship between accumulated playing time during the regular season and key characteristics of international football tournaments, we focus on four dependent variables that align with the hypotheses outlined above: the average number of goals scored per match, the average goal difference, the average number of yellow cards, and the average number of red cards. Each variable is calculated by adding up the relevant match-level observations across all matches in a given tournament and dividing that figure by the total number of matches played.

For tournament $t$ with $Mt$ matches, each dependent variable $yt$ is defined as: $yt$ = $(1Mt)∑m=1Mtym,t$ , where $ymt$ is the match-level observation for match $m$⁠. For example, goal difference in match $m$ is $|goalsa−goalsb|$⁠; if a tournament has 51 matches with goal differences summing to 62, the average goal difference per match equals 62/51 ≈ 1.22. Regular-season minutes for player $i$ in season $s$ are defined as the total minutes played in domestic league matches only, excluding domestic cup ties, European club competitions, and international fixtures. For each season, this figure is drawn from Transfermarkt's match-by-match records. To harmonize seasons across leagues with different calendar structures (e.g. the August–May schedule of European leagues versus the January–December structure of some South American leagues), we assign each season to the calendar year in which the summer international tournament falls: the proxy for, say, Euro 2024 is constructed from the 2023/24 season across all leagues, defined as the last completed domestic league season before the start of that tournament.

Historical data for the FIFA World Cup were obtained from the FIFA's official historical archive, while data on continental football tournaments (e.g. the UEFA European Championship and the Copa América) were gathered from the Rec.Sport.Soccer Statistics Foundation (RSSSF), one of the most comprehensive and long-standing digital archives dedicated to international football. RSSSF is an independent network of researchers, sports historians, and contributors that has compiled a large corpus of structured textual data over several decades, drawing on official documents, federation records, historical publications, and archival material. The data are published in a static, text-based format and are not generated from relational databases or standardized APIs.

For the purpose of this study, the data were manually extracted and reorganized into harmonized tables. For the European Championship, the dataset includes, for each match, the tournament year, competition stage, referee, participating teams, goals scored by each side, and (where applicable) extra time, penalty shootouts, and disciplinary actions. A similar structure was applied to the Copa América dataset, with minor adjustments to account for the tournament's specific historical and organizational characteristics.

The data construction process followed a consistent normalization protocol to ensure comparability across editions and competitions. Although the original sources are textual and non-automated, their historical depth and the rigor of their compilation make them reliable for quantitative comparative and longitudinal analysis. The resulting tournament-level averages capture multiple dimensions of match dynamics, including offensive output, competitive balance, and disciplinary intensity.

Given the count nature of the dependent variables, we employ a Poisson regression framework to estimate the relationship between playing time and tournament outcomes. Since our dependent variables (goals scored, goal difference, yellow cards, and red cards per match) are non-negative count variables, the Poisson model is theoretically appropriate. It assumes equality between the conditional mean and variance, a property well-suited for tournament-level aggregates where overdispersion is limited. As noted by Cameron and Trivedi (1998), Poisson models offer consistent and efficient estimates under mild assumptions and are particularly advantageous for small samples with low frequencies, as in our case. The exponential functional form ensures non-negative predicted values, aligning with the structure of our outcomes.

The Poisson quasi-maximum likelihood estimator yields consistent estimates under a correctly specified conditional mean even when outcomes take non-integer values, and without requiring the dependent variable to follow a Poisson distribution, as established by Gourieroux et al. (1984) and subsequently applied in a wide range of economics contexts including sports economics.

Our primary independent variables are the mean and median minutes played during the regular season by the 50 most-utilized players preceding each tournament, computed separately for players from the top-five European leagues and from all professional leagues worldwide. This macro-level proxy is not merely a data constraint but reflects the nature of the research question: how the progressive intensification of the global football calendar reshapes international tournament dynamics at the aggregate level. The top-50 proxy is highly correlated with the workload of actual tournament participants, since national squads are disproportionately drawn from the most active club players.

While imperfect, this approach provides a consistent, comparable, and empirically grounded measure of player usage across time and contexts. Focusing on the top five European leagues also enables us to isolate the impact on players in international competitions. This choice is empirically grounded: as Figure 6 shows, more than 66% of participants in recent major international tournaments (FIFA World Cups 2018; 2022; UEFA Euro 2024) were drawn from these leagues, underscoring their central role as producers of global football talent and as key shapers of the technical and tactical standards of international play.

Importantly, this percentage likely underestimates the true influence of players from the top five leagues, as host nations automatically qualify for these tournaments and often include players from local or lower-tier leagues, slightly inflating the representation of the “All Leagues” category. Nevertheless, the overwhelming presence of players from elite European clubs remains evident, validating the analytical emphasis placed on these leagues. Methodologically, this focus ensures that the analysis targets the segment of professional football where player exposure, competitive intensity, and fixture congestion are most acute, making it particularly suited to study the dynamics and consequences of cumulative player workload.

We include dummy variables for tournament type (UEFA Euro and Copa América, with the World Cup as reference category) to control for structural differences across competitions. The limited sample (N = 43) constrains the model to a maximum of four independent variables, following the rule of thumb of 10–15 observations per regressor (Babyak, 2004). This is a structural constraint, not a design choice: major international tournaments occur infrequently by definition.

To investigate whether fatigue affects player types differently, we extend our empirical design to incorporate role-specific measures of playing time. Specifically, we compute the mean and median regular season minutes for each positional group (i.e. defenders, midfielders, forwards, and goalkeepers) within the top 50 most-utilized players. These variables are included in additional regressions to explore whether seasonal workload for specific positions correlates more strongly with tournament-level indicators of spectacle and discipline. This disaggregated approach provides a more nuanced understanding of how accumulated physical demand across positions may influence the quality and intensity of elite international football.

More specifically, the empirical model is estimated using a Poisson regression, which is appropriate for the count-based nature of the dependent variables. Let $yt$ denote one of the four proxies for tournament-level spectacle or disciplinary intensity in tournament t (i.e. the average number of goals per match, the average goal difference, the average number of yellow cards, or the average number of red cards). The core specification is given by:

where $Eurot$ and $Copat$ are dummy variables indicating whether tournament t is a UEFA European Championship or a CONMEBOL Copa América, respectively, with the FIFA World Cup serving as the omitted, and hence reference, category. The variable $Mint$ represents the key independent variable of interest, either the mean or the median number of minutes played during the regular season by the 50 most-utilized players in year t, using either the top five European leagues or all leagues combined. In extended specifications, this variable can also refer to role-specific averages, such as average minutes played by defenders, midfielders, forwards, or goalkeepers, within the same framework (i.e. 50 most-utilized players). The exponential functional form ensures the non-negativity of the predicted outcomes and allows for an intuitive interpretation of coefficients as semi-elasticities, facilitating a direct assessment of how variation in seasonal player workload relates to the offensive output and disciplinary profile of international football tournaments.

The dataset underlying our analysis includes all major international tournaments for which reliable data on regular-season minutes played were available. Specifically, we focus on the final stages of the FIFA World Cup, UEFA European Championship, and CONMEBOL Copa América, covering the period from the Euro 1976 to the Copa América 2024. For each tournament year, we calculate the mean and median regular-season minutes played by the 50 players with the highest seasonal workloads in that year. As noted earlier, these players are not necessarily participants in the respective tournaments; rather, this measure serves as a proxy for the intensity of player usage at the highest levels of professional football during the seasons preceding each competition. While this approach does not directly track tournament participants, it captures the broader conditions of physical load and fixture congestion under which international players are assembled.

The final sample comprises 43 tournament-level observations. Tournament-level aggregation reduces noise relative to match-level data and Poisson models perform reliably in small well-specified samples. The dataset underlying our analysis covers all final phases of the FIFA World Cup, UEFA European Championship, and CONMEBOL Copa América from Euro 1976 to Copa América 2024. Descriptive statistics are reported in Table 1 in the Online Appendix.

To further assess the robustness and reliability of our estimates in the context of a relatively small sample, we implement a jackknife resampling procedure. The jackknife is a non-parametric technique that evaluates the sensitivity of statistical estimates to individual data points. By systematically excluding one observation at a time from the sample and re-estimating the model, the jackknife allows us to evaluate the influence of each tournament on the overall regression results and to assess the stability of the estimated coefficients across subsamples. Originally introduced by Quenouille (1949) and extended by Tukey (1958), the jackknife is particularly well suited to small samples because it does not rely on distributional assumptions and avoids the data fragmentation that can occur with bootstrap procedures when observations are few and discrete. The jackknife estimate of variance for a parameter is derived from the variation in estimates obtained from the leave-one-out subsamples. In our application, this entails estimating 43 Poisson regressions, each omitting one data point, and examining the distribution and variance of the resulting coefficients.

This technique reveals whether any single tournament year disproportionately influences the direction or significance of findings, and confirms whether estimated associations are stable across subsamples. Estimated associations are directionally consistent across all specifications (both mean- and median-based proxies, and both top-five and all-league subsamples) providing empirical reassurance beyond formal hypothesis testing.

The Poisson regression estimates are reported in full in Tables 2 and 3 of the Online Appendix, while Figures 7 to 10 summarize the key coefficients. All models are estimated separately using mean and median seasonal minutes, for the top-five European leagues and all leagues combined. Tournament dummies for the Euro and Copa América control for competition-specific effects, with the World Cup as the reference category.

The tournament dummies yield consistent and interpretable results. Across specifications, neither the Euro Cup nor the Copa América exhibits a statistically significant effect on the total number of goals scored per match, suggesting no systematic difference from the World Cup in aggregate offensive output. However, both competitions are strongly associated with significantly lower average goal differences, indicating that matches in these regional tournaments tend to be more evenly balanced than the World Cup, possibly reflecting differences in seeding, preparation, or competitive parity.

Turning to the core explanatory variables, regular season playing time does not exhibit a statistically significant association with the average number of goals per match. Coefficients for both mean and median minutes, whether based on top five leagues or all leagues, are not significant, providing no empirical support for hypothesis H1.

By contrast, average goal difference per match shows a statistically significant negative association with seasonal minutes. For example, the coefficient for median minutes in the top five leagues is −0.00158 (p < 0.01), implying that each additional minute reduces the expected goal difference by approximately 0.16% (exp(−0.00158) ≈ 0.9984). Put differently, an increase of one additional match per season (about 90 min) would be associated with a 14.4% reduction in goal difference. This effect also appears in the all-league specification, where the coefficient reaches −0.00181 (p < 0.01). These findings suggest that tournaments following seasons with heavier player workload tend to produce closer contests with narrower margins of victory, possibly due to the leveling effects of fatigue across stronger and weaker teams, thus offering partial empirical support for hypothesis H2.

Regarding disciplinary outcomes, yellow card frequency is positively and significantly associated with seasonal playing time. Across all specifications, higher median or mean minutes are linked to more yellow cards per match. For instance, in the all-league sample, the coefficient for median minutes is 0.00157 (p < 0.01), indicating that a one-minute increase in seasonal workload raises the expected number of yellow cards by approximately 0.16% (exp(0.00157) ≈ 1.0016). This finding supports hypothesis H3, suggesting that accumulated fatigue heightens the likelihood of minor infractions, potentially due to slower reaction times or reduced physical control.

Red card incidence, by contrast, shows a robust and statistically significant negative association with player workload. In the all-league specification using median minutes, the coefficient is −0.00236 (p < 0.01), implying that each additional minute of seasonal workload reduces the expected number of red cards per match by approximately 0.24% (exp(−0.00236) ≈ 0.9976). This outcome runs counter to hypothesis H4. Although initially counterintuitive, this result may reflect a behavioral adjustment among fatigued players and teams, who adopt more risk-averse strategies to avoid serious fouls and players getting sent off. Figures 7 to 10 further indicate that these associations are broadly consistent across positions, with only minor deviations observed for goalkeepers.

Overall, seasonal playing time does not suppress scoring but contributes to closer contests and a shift in the disciplinary profile of international tournaments. The mechanisms underlying these patterns are discussed in full in Online Appendix; a brief summary follows.

The absence of a significant effect on goals per match likely reflects offsetting mechanisms: ex-ante squad rotation by coaches, the technical resilience of high-minute players, game-theoretic equilibria favoring mutual conservatism, and threshold effects whereby fatigue impairs execution quality without reducing scoring opportunities.

The shift from three to five permitted substitutions may have further buffered the observable impact of fatigue on scoring in recent tournaments, suggesting that reported associations may understate the true relationship under the pre-2020 regime.

The negative association between workload and goal difference likely reflects an equalizing effect of fatigue: stronger teams, whose players accumulate heavier workloads, lose some of their physical advantage, producing tighter contests. Tactical conservatism and game-theoretic convergence towards lower-risk equilibria reinforce this pattern.

The asymmetric disciplinary pattern (more yellow cards, fewer red cards) reflects the nature of fouls under fatigue: tired players commit minor tactical infractions rather than explosive, reckless challenges, consistent with heuristic decision-making (Raab, 2012), impaired cognitive control (Smith et al., 2016), and the superior self-regulatory capacity of elite athletes (Mazzanti et al., 2025).

While average goals per match are unaffected, the broader spectacle of international football is reshaped by accumulated workload. Closer contests (narrower goal differences) may heighten competitive suspense; more yellow cards and fewer red cards suggest more interrupted but less violent play. Cumulative fatigue thus dampens certain dimensions of spectacle while intensifying others.

This article set out to examine trends in regular-season minutes played by professional footballers, and to assess whether their accumulation is associated with the structure and dynamics of international tournaments. A central objective was to provide a long-run descriptive account of player usage, with particular attention to differences between athletes competing in the top five European leagues and those active in the broader set of professional leagues worldwide. The empirical analysis covered all final phases of the FIFA World Cup, UEFA European Championship, and CONMEBOL Copa América from 1976 to 2024, focusing on four key tournament-level indicators: average number of goals per match, average goal difference, and average numbers of yellow and red cards per match.

The descriptive evidence confirms a sustained rise in seasonal playing time among the most heavily utilized professional footballers over five decades, with top-five league players now approaching the workload levels historically seen in lower-rotation leagues. This convergence suggests that fixture congestion is eroding the conditioning advantage of elite national squads, potentially contributing to the tighter competitive margins observed in recent international tournaments.

Building on this empirical backdrop, the article employed Poisson regression models to test whether variation in seasonal player playing time is associated with changes in tournament-level outcomes. While no statistically significant effect emerged for the average number of goals per match, the analysis uncovered a robust negative association between player workload and goal difference. Tournaments following seasons with higher cumulative minutes tended to produce more evenly contested matches, potentially reflecting the equalizing effect of fatigue across national teams. In addition, greater seasonal usage was positively associated with the average number of yellow cards per match, supporting the idea that fatigue may elevate the risk of minor infractions. Conversely, red card incidence decreased with higher workloads, possibly indicating more cautious or risk-averse tactical behavior under physical strain.

Together, these findings indicate that while cumulative player workload may not directly suppress scoring outright, it does appear to influence the competitive balance and disciplinary profile of international tournaments. The narrowing distribution of goal differences and the shifting patterns of foul behavior reflect deeper structural pressures rooted in the modern football calendar. As governing bodies continue to expand international competitions, including the launch of the FIFA Club World Cup, this research highlights the importance of understanding how seasonal usage patterns shape the quality and nature of the sport's most prestigious events. The results point to a growing need for coordination between domestic and international scheduling to safeguard both player welfare and competitive integrity.

In addition to documenting long-term trends in minutes played by professional footballers, this study offers new empirical evidence on the relationship between seasonal player usage and international tournament dynamics. Nonetheless, several limitations constrain the scope and interpretation of the results.

Several limitations should be noted. The workload proxy (top-50 seasonal minutes) is an aggregate measure and may not perfectly reflect the actual fatigue of specific tournament participants. Tournament-level averaging masks within-tournament heterogeneity. The sample (N = 43) limits statistical power and the inclusion of additional controls, a structural constraint that cannot be remedied by demanding richer specifications. Finally, the analysis does not directly measure physiological fatigue or control for rule changes and contextual shifts. These limitations are discussed in full in Online Appendix.

These limitations notwithstanding, the approach adopted here offers a consistent and historically grounded framework for evaluating how the intensification of the professional calendar may reshape the character of international football. Future research incorporating biometric data, GPS-derived intensity measures, or data on player recovery periods would allow for a more precise identification of the mechanisms through which seasonal exposure shapes international performance.

This article was refined with the assistance of ChatGPT to improve clarity and flow; the authors have reviewed the final version and take full responsibility for its content.

The supplementary material for this article can be found online.