This study was conducted to determine if the acute: chronic workload ratio (ACWR) is related to the incidence of non-contact injuries. The purpose is to compare the external load of injured and non-injured soccer players with the same characteristics, such as position and age. The present analysis considers both the four and the two weeks preceding an injury. Physical characteristics were recorded and analyzed through global positioning systems (GPS) evaluation over one season of 24 competitive microcycles, 144 training sessions, and 32 matches in a total of 35 professional soccer players from the Greek Super League 1 and Super League 2. The loads calculated were total distance (TD), 15–20 km/h, 20–25 km/h, 25–30 km/h, accelerations (ACC) > 2.5 m/s², and decelerations (DEC) > 2.5 m/s²). Nine injured athletes exceeded the critical threshold of an ACWR > 1.3 several times compared with non-injured athletes that did not reach this level. The present study showed that ACWR is related to a subsequent occurrence of injury but that the threshold of an ACWR can vary. This seems to be mainly influenced by assessing the load of the last two weeks compared with that of the four weeks before the injury.

This study examined acute pre- to post-match changes in perceived mental fatigue, subjective workload, and psychomotor performance in professional male soccer players, and whether cognitive changes were associated with GPS-derived external-load metrics, match outcome, and playing position. The dataset comprised 101 player–match measurements from 40 elite players, with paired pre–post psychomotor assessments yielding n = 202 total measurements. Pre–post comparisons were analysed using repeated-measures ANOVA, supplemented by linear mixed-effects models with a random intercept for player. Soccer matches produced large increases in perceived exertion, mental fatigue, mental demand, physical demand, and effort (all p < 0.001), and significant deteriorations in reaction time, accuracy, processing speed, and response variability (all p ≤ 0.005), confirmed in the mixed-effects analyses (all p ≤ 0.014). In the initial player–match-level analyses, high-intensity accelerations (>3 m·s⁻²) were weakly associated with greater Δreaction-time slowing (r = 0.203), increased response variability (r = 0.276), and reduced Rate Correct Score (r = −0.242), while high metabolic load distance was weakly associated with post-match perceived mental fatigue but not with psychomotor-performance changes. One-way ANOVAs indicated greater post-match psychomotor decrements following losses than draws. Once within-player dependence was modelled, the effects of match outcome, playing position, and most external-load metrics were attenuated, except for a residual match-outcome effect on accuracy and a high-intensity deceleration effect on accuracy. These findings indicate that competitive soccer match play is followed by acute psychomotor-performance decrements and increased perceived mental fatigue, whereas the contributions of mechanical load, match outcome, and playing position appear modest and partly reflect stable between-player differences.

The aim of this study was twofold: (a) to examine the differences on physical indexes between players of different playing positions and (b) to reveal the correlations between their physical parameters and the running profile within the weekly microcycles. The subjects (n = 44) were separated into five positions: central defenders (n = 7), wide defenders (n = 9), midfielders (n = 13), wingers (n = 8) and strikers (n = 7), and all of them belonged to a professional 1st division European team during the 2020–21 and 2021–22 seasons. An incremental treadmill protocol was used to assess the VO₂max, vVO₂max and the vRER in the last week before the regular season. Then, during the first semesters, external load data were collected for two consecutive seasons to analyze the running profiles of the different positions. There were no differences on physical parameters between the players of various positions, but interestingly there were different correlations with the external load during the microcycles. Central defenders did not show any correlation. For the other positions, correlations were found between respiratory exchange ratio (vRER) and metabolic power efforts (MPWEF) (p = 0.028, r = 0.721) for wide defenders, between vRER and medium intensity accelerations (ACC2) (p = 0.004, r = 0.741) for midfielders, medium intensity decelerations (DEC2) (p = 0.01, r = 0.685), metabolic power zone 5 (MPW5) (p = 0.016, r = 0.652), MPWEF (p = 0.005, r = 0.725), and also between maximal rate of oxygen consumption (VO₂max) and high intensity decelerations (DEC3) (p = 0.045, r = 0.564), metabolic power zone 4 (MPW4) (p = 0.026, r = 0.614), MPW5 (p = 0.017, r = 0.646), MPWEF (p = 0.01, r = 0.685). A correlation between velocity on VO₂max (vVO₂max) and ACC2 (p = 0.038, r = 0.733), MPW5 (p = 0.005, r = 0.873), and MPWEF (p = 0.009, r = 0.84) was found for the wingers. Finally, there was a correlation between vRER and MPWEF (p = 0.026, r = 0.866), and between vVO₂max and high intensity accelerations (ACC3) (p = 0.03, r = 0.801) for the strikers. Our study supports that the external load of players in different positions during the training sessions is correlated with their physical indexes. These correlations are determined mostly by their tactical role, but not from their physical level, as there were no differences.

The aim of this study was to record and interpret external load parameters in professional soccer players in competitive microcycles with one or two matches per week, while investigating the interaction between training load and non-contact musculoskeletal injuries during training and matches. Musculoskeletal injuries in athletes are closely associated with workload fluctuations, particularly the acute:chronic workload ratio (ACWR) over preceding weeks. This study analyzed the physical workload of 40 high-level soccer players competing in the Greek championship across two seasons, encompassing 50 competitive microcycles, 60 official matches, and 300 training sessions. GPS-based assessments recorded total distance (TD), running speeds (15–20 km/h, 20–25 km/h, 25–30 km/h), accelerations (>2.5 m/s²), and decelerations (>2.5 m/s²). An independent sample t-test was conducted to compare injured and uninjured athletes, with statistical significance set at p < 0.05. Results showed that 20 injured athletes frequently exceeded the ACWR threshold (>1.3) compared to uninjured players. Analysis of the four weeks preceding the injury revealed that increased workload in high-intensity categories significantly contributed to non-contact injuries. Specifically, high running speeds of 15–20 km/h (p = 0.015), 20–25 km/h (p = 0.045) and >25 km/h (p = 0.008), as well as accelerations (p = 0.010), were linked to a higher risk of injury. The three-week ACWR model indicated statistically significant differences in the ACWR index for total distance (p = 0.033), runs at 15–20 km/h (p = 0.007), >25 km/h (p = 0.004), accelerations (p = 0.009), and decelerations (p = 0.013). In the two-week model, significant differences were found in runs at 15–20 km/h (p = 0.008) and >25 km/h (p = 0.012). In the final week, significant differences were observed in runs at 15–20 km/h (p = 0.015), >25 km/h (p = 0.016), and accelerations (p = 0.049). Additionally, running speeds of 25–30 km/h (p values between 0.004 and 0.016) played a key role in injury risk when limits were exceeded across all weekly blocks. These findings highlight the importance of monitoring ACWR to prevent injuries, particularly by managing high-intensity workload fluctuations in elite athletes.

Background and Objectives: This study aimed to assess the week-by-week predictive value of Acute:Chronic Workload Ratios (ACWRs) for non-contact injury risk in professional soccer players. Materials and Methods: A cohort of 40 elite players was monitored using GPS over two competitive seasons. Binomial logistic regression and ROC curve analyses were performed on ACWR metrics—including total distance, moderate-to high-speed running, sprinting, acceleration, and deceleration—during the four weeks prior to injury (W4 to W1). p-values were further adjusted for multiple comparisons using the false discovery rate (FDR) correction (q < 0.05). Results: Significant predictive models emerged mainly for ACWR metrics related to moderate-speed running (15–20 km/h), sprinting (>25 km/h), and acceleration/deceleration. The ACWR for 15–20 km/h (DSR15–20) demonstrated the highest predictive accuracy, particularly in Week 3 (AUC = 0.811, p = 0.004). Sprinting (DSR>25) was also significantly associated with injury occurrence across Weeks 1–4 (AUC = 0.709–0.755, p = 0.011–0.024). Acceleration (ACC) and deceleration (DEC) metrics showed significant associations prior to correction—ACC in Weeks 3–4 (AUC = 0.737–0.755, p = 0.020–0.026) and DEC in Weeks 3–4 (AUC = 0.720–0.741, p = 0.029–0.043)—but these associations did not retain significance following FDR adjustment (q = 0.052–0.086). In contrast, total distance (ACWR TD) and high-speed running (20–25 km/h) were weaker predictors, reaching only marginal or nonsignificant levels (e.g., Week 3, AUC = 0.675, p = 0.054). After FDR correction, only DSR15–20 and DSR>25 remained statistically significant (q < 0.05), confirming them as robust predictors of non-contact injury risk. Multivariable models adjusted for age and playing position confirmed these findings, with DSR15–20 and DSR>25 retaining their predictive value independent of confounding factors. Injury risk thresholds were established through Estimated Marginal Means (EMMs), defining the “Sweet Spot” and “Danger Zone” for each metric, whereas the “Low Load” zone was treated as exploratory. Conclusions: This weekly ACWR monitoring approach enables practical injury risk profiling, helping training staff optimize load management and minimize non-contact injury risk in elite soccer.