As previous literature updates, I have performed a PubCrawler search looking for football articles in NCBI Medline (PubMed) and GenBank databases.

Following studies were retrieved for this week:

1 Reliability of self-reported career histories reported by former professional association football players included in the health and ageing data iN the game of football (HEADING) study

Reference: Ann Work Expo Health. 2026 May 12;70(4):wxag032. doi: 10.1093/annweh/wxag032.
Authors: Ioannis Basinas, Helena Copsey, Fiona S Carson et al.
Summary: The aim was to assess the ability of former professional association football players in England to recall their playing careers. Self-reported data regarding playing careers were available from former professional football players participating in the Health and Ageing Data IN the Game of football (HEADING) study. We compared the self-reported data from 141 participants regarding the teams, positions, periods, and leagues they played for against the data available in publicly available records, compiled with the assistance of the English Professional Footballers‘ Association. Self-reporting of career histories occurred a mean of 28.5 years since the players had their last competitive season. Overall, 20 discrepancies between self-reported and register-based data were observed in the career histories of 18 (12.8%) individual players. This is in line with data from earlier reliability studies on the self-reporting of occupational histories. The most common error observed was incorrect recording of years of play in certain clubs, occurring in 9 instances. Missing teams in self-reports were observed in another 8 cases. The results suggest that former professional association football players can provide plausible information over long periods regarding the general characteristics of their professional career. This information could form the basis for a reliable exposure assessment within epidemiological analyses. Further work is required to assess recall of the amount of heading and other head impacts during training and play.

2 Predictive modeling of injury risk based on body composition and physical fitness performance tests in professional football: A four-year study

Reference: J Sports Sci. 2026 May 14:1-15. doi: 10.1080/02640414.2026.2673250. Online ahead of print.
Authors: Francisco Martins, Élvio Rúbio Gouveia, Krzysztof Przednowek, Edson Palomares, Davi Vale, Hugo Sarmento
Summary: Preventing sports injuries in professional football enhances players‘ availability and performance. Machine learning, including artificial neural networks, provides the opportunity to build multivariable prognostic prediction models that can help develop personalised risk estimations for injury occurrence. This study aims to construct predictive methods for injury risk based on selected body composition and physical fitness in professional football players across four seasons. The study sample comprised of 121 professional football players (26.1 ± 4.2 years old) who represented this team over the study period. The investigation was conducted according to three methodological sets of assessments: (i) average season, (ii) initial performance, and (iii) 2 weeks before injury. The primary classifier to predict injury risk was the K-star, which had a sensitivity of 81%. This method used data from 2 weeks before injury, including age, experience, body composition and lower-limb explosive strength. In application, regular body composition assessments and lower-limb explosive strength seemed more accurate in predicting muscle injury occurrence in this specific professional club. Predictive models learned from real-world training data and injury information can significantly aid early detection of injury risk. Future research could be valuable if longitudinal studies with classification methods use external and internal workload data.

3 Epidemiology of injuries across multiple male professional football academies within Club Academy Scotland

Reference: J Sports Sci. 2026 May 13:1-10. doi: 10.1080/02640414.2026.2673244. Online ahead of print.
Authors: Steven Curnyn, Mark Leslie, Sean Cumming, Debbie Palmer, Sean Williams
Summary: Injuries can negatively impact the development of academy footballers through time lost from training and matches. Reducing injury risk is therefore a priority. This study analysed 545 male players (U11-U18; age range 9-17) across five academies in Club Academy Scotland (CAS) during the 2024/2025 competitive season. Injury incidence (per 1000 hours), severity (mean and median days lost), and burden (days missed per 1000 hours) were recorded for both contact and non-contact injuries. Exposure included all training and match hours. Overall injury incidence, severity, and burden were substantially higher in matches than in training (8.53 vs. 2.21 per 1000 hours, 28 vs. 20 days, and 236 vs. 44 days lost per 1000 hours, respectively). The U14 age group recorded the highest match injury incidence and burden (15.95 per 1000 hours and 510 days lost per 1000 hours). In training, non-contact injuries occurred more frequently than contact injuries (1.78 vs. 0.43 per 1000 hours), predominantly affecting the knee and ankle/heel. Muscle tears and sprains were the most common injury types. The high proportion of non-contact lower limb injuries suggests that targeted neuromuscular training programmes may be beneficial, particularly for mid-adolescent players. .

4 The effects of an 8-week Exer-Genie-assisted speed and ABC drill training program on speed, hamstring strength, and vertical jump performance in female football players

Reference: BMC Sports Sci Med Rehabil. 2026 May 13. doi: 10.1186/s13102-026-01744-3. Online ahead of print.
Authors: Yusufcan Keskin, Mehmet Yavuz Taşkıran, Gürkan Elçi
Download link: https://link.springer.com/content/pdf/10.1186/s13102-026-01744-3_reference.pdf
Summary: The increasing physical demands of modern women’s football necessitate integrated training approaches capable of simultaneously enhancing acceleration, force production, and neuromuscular control. Although devices such as the Exer-Genie® are frequently implemented in resisted sprint training, scientific evidence regarding their effectiveness in adolescent female athletes remains limited. Therefore, this study aimed to examine the effects of an eight-week Exer-Genie®-assisted speed and agility-balance-coordination (ABC drill) training program on sprint performance, hamstring muscle strength, and vertical jump performance in young female football players. A total of 37 licensed female football players competing in the Turkish Women’s Second League (mean age = 14.4 ± 1.4 years) voluntarily participated in the study. Participants were randomly assigned to an experimental group (n = 20) or a control group (n = 17). The experimental group completed an Exer-Genie®-assisted sprint and agility-balance-coordination training program twice per week for eight weeks, while the control group continued their regular training. Pre- and post-intervention assessments included 0-10 m, 10-30 m, and 30 m sprint performance, hamstring muscle strength and impulse values, and countermovement jump performance.Data were analyzed using repeated-measures ANOVA. Significant time × group interactions were observed for 0-10 m sprint time (3.9% improvement; F = 10.17, p = .003, η² = 0.038) and 30 m sprint time (3.8% improvement; F = 21.08, p < .001, η² = 0.020). Hamstring maximal strength increased by approximately 20% (left: F = 15.94, p < .001, η² = 0.03), while hamstring impulse improved by approximately 36% (left: F = 10.62, p = .002, η² = 0.05; right: F = 9.75, p = .004, η² = 0.03). No significant improvements were observed in lower-limb strength asymmetry. Eight weeks of Exer-Genie®-assisted speed and ABC drill training significantly enhanced acceleration and hamstring strength parameters in young female football players. The observed improvements (~ 4% in sprint performance, ~ 20% in maximal strength, and ~ 36% in impulse capacity) support the potential usefulness of combining resisted sprint training with neuromuscular coordination drills.

5 Three-Season Analysis of Physical Performance in Professional English Football: Influence of Match Outcome, Match Location, and Players‘ Position During Official Competitions

Reference: J Strength Cond Res. 2026 May 13. doi: 10.1519/JSC.0000000000005410. Online ahead of print.
Authors: Marco Beato, Matt Allen, Mikael Jamil, Jordi Vicens Bordas
Summary: This study presents a unique longitudinal analysis of physical performance across 3 consecutive seasons of the same professional English football club, capturing its progression from League One to the Championship and ultimately to the Premier League. Using official match data, the investigation aimed to determine how physical performance metrics are influenced by contextual factors including match outcome, location, and playing position. Players ( n = 49) were categorized into 5 positional groups: center backs, wing backs, center midfielders, attacking midfielders, and strikers. Matches were classified by outcome (win, draw, loss) and location (home, away), with player positions assigned based on in-game roles. Global navigation satellite systems-derived metrics included total distance covered, high-speed running (HSR), sprinting distance, and high-intensity distance (HID), alongside counts of high-intensity accelerations and decelerations. Significant effects were found for season ( p = 0.005), match outcome ( p = 0.031), and position ( p < 0.001) on total distance; for season ( p < 0.001), match outcome ( p = 0.010), and position ( p < 0.001) on HSR; and for season ( p < 0.001), match outcome ( p = 0.024), and position ( p < 0.001) on sprinting distance. High-intensity distance was significantly influenced by season ( p < 0.001), match outcome ( p = 0.009), and position ( p < 0.001). Accelerations ( p = 0.004) and decelerations ( p < 0.001) were significantly affected only by position. Match location showed no significant effect except on sprinting distance. These findings highlight the increasing physical demands across competitive tiers and emphasize the importance of tailoring physical preparation to both league level and positional requirements.

6 The fine line between deliberate play and deliberate practice within talent development in grassroots football: evidence from a one-year longitudinal case study

Summary: Front Sports Act Living. 2026 Apr 27:8:1799878. doi: 10.3389/fspor.2026.1799878. eCollection 2026.
Authors: Dag Vidar Hanstad, Eivind Å Skille, Bjørn Tore Johansen, Anna-Maria Strittmatter
Download link: https://pmc.ncbi.nlm.nih.gov/articles/PMC13158181/pdf/fspor-08-1799878.pdf
Summary: While former studies into talent development in football have considered elite clubs and retrospective studies, this single-case study provides detailed data on the training activities of a 13-year-old male football player in a grassroots club who later became a professional at the highest level in Norway. An intrinsic longitudinal single-case study design was adopted to develop an in-depth, contextually grounded understanding of the load and forms of physical activity within and beyond organized football as performed and experienced by one specific player over the course of a full year in a grassroots football environment. The empirical material includes daily logging and categorization of all activities in a training dairy, with notes provided by the player – and supplemented with in-depth semi-structured interview with the player. The dataset comprises 733 h of activity over one year, the majority of which consisted of organized football-specific activity (team training: 196 h; matches including warm-up: 84; private football academy training: 110). In addition, the player engaged in 157 h of unorganized football (alone: 79; with friends: 78), sport-related school activities (physical education: 59; unorganized football play in the schoolyard: 28), and 99 h of individual non-football-specific training such as strength training, injury-prevention exercise, and recreational activities including cross-country skiing and family leisure. This case from grassroots football demonstrates substantial variation between deliberate practice and deliberate play. Two categories that are conceptually distinct yet appear equally important in the developmental pathway. At the same time, some training forms represent a blend of play and practice. For instance, unorganized football with friends in this study displays several characteristics typically associated with deliberate practice, whereas team training with a coach also contains elements of play.

7 Development and Validation of a Kinetics Prediction Model for Football Cutting Using a Single Trunk-Mounted IMU

Reference: Sensors (Basel). 2026 Apr 28;26(9):2741. doi: 10.3390/s26092741.
Authors: Inae Kim, Soo-Ji Han, Joong Hyun Ryu, Sanghyuk Han, Jinsung Yoon, Jongchul Park
Download link: https://www.mdpi.com/1424-8220/26/9/2741
Summary: This study aimed to estimate vertical ground reaction force (vGRF) and lower-limb joint moments during football cutting movements using a trunk-mounted inertial measurement unit (IMU) combined with a Random Forest model, and to validate the feasibility of this approach. IMU data collected during 45° cutting tasks were corrected using an Extended Kalman Filter (EKF). The model demonstrated good and consistent performance for vGRF (coefficient of determination, R2 = 0.766; correlation coefficient, r = 0.796) and sagittal plane moments of the ankle and knee (R2 = 0.661-0.689, r = 0.807-0.842). While Bland-Altman analysis indicated low bias and generally good agreement, precision at the individual-trial level and accuracy for non-sagittal plane moments somewhat reflected the inherent within-player trial-to-trial variability in movement execution, particularly in non-sagittal loading patterns. It should be noted that performance estimates under the current trial-based validation design may differ from those obtained using a subject-independent framework such as leave-one-subject-out cross-validation. This study demonstrates that a single trunk-mounted IMU can reliably estimate key lower-limb loading patterns, providing a practical foundation for wearable-based kinetic monitoring in applied football settings.

8 YOLOv8 computer vision for automated offside detection in professional football validated through supervised learning

Reference: Sci Rep. 2026 May 11. doi: 10.1038/s41598-026-52668-4. Online ahead of print.
Authors: Abdul-Rahman Abdel-Fattah, Samir Brahim Belhaouari, Halil İbrahim Ceylan, Serdar Bayrakdaroğlu, Raul Ioan Muntean, Wissem Dhahbi, Ismail Dergaa, Abdelfatteh El Omri
Download link: https://www.nature.com/articles/s41598-026-52668-4_reference.pdf
Summary: Offside calls are integral to maintaining fairness and competitive integrity in football, yet current officiating processes are constrained by limitations in accuracy despite technological advancements. This investigation developed and validated an automated offside detection system using YOLOv8 object detection architecture to address documented limitations of Video Assistant Referee (VAR) systems in offside decision accuracy. Supervised learning validation employed 400 annotated instances from professional match footage. The YOLOv8 medium variant was configured for four-class detection, with a focus on extreme player positions, reducing computational complexity by approximately 70% relative to comprehensive player tracking while accepting accuracy trade-offs in marginal scenarios. The system was optimized for computational efficiency through highly accurate tracking of player positions. Data were partitioned into 40% (n = 160) for training and 60% (n = 240) for testing, with 5-fold cross-validation. The automated system achieved robust performance metrics across 240 test instances: overall accuracy of 83.0%, precision of 85.0%, recall of 87.0%, and F1-score of 86.0%. Confusion matrix analysis revealed true positives (n = 130), true negatives (n = 70), false positives (n = 22), and false negatives (n = 18). Individual case analysis demonstrated 80% agreement with ground truth classifications. System performance significantly exceeded the random classification baseline (p < 0.001). The strategic extreme player tracking approach achieved substantial computational efficiency while maintaining decision accuracy across diverse match scenarios. A YOLOv8-based offside detection system demonstrates proof-of-concept feasibility for decision-support applications in football officiating. Performance (83% accuracy, 95% CI: 79-87%) on 240 test instances remains below professional benchmarks (> 93%), with single-camera constraints and limited dataset size restricting generalizability to proof-of-concept validation rather than operational deployment.

9 Effects of Functional Inspiratory Muscle Training Based on Core Stability Exercise on Respiratory Functions and Physical Performance in Football Players

Reference: J Strength Cond Res. 2026 May 7. doi: 10.1519/JSC.0000000000005397. Online ahead of print.
Authors: Yunus Emre Tütüneken, Kübra Kardes, Elif Kabasakal, Eda Nur Çakir, Atilla Can Kalay, Görkem Tetik, Elif Sude Deliktaş
Summary: Inspiratory muscle training is recognized as a potential strategy to enhance performance. This study compares the effects of a program that incorporates Functional Inspiratory Muscle Training (FIMT) based on Core Stability Exercise with Core Stability Training (CST) in football players. Thirty subjects were randomly assigned to either the FIMT group or the CST group. Both programs were conducted over 6 weeks, with five 45-minute sessions each week, alongside regular training routines. Outcomes measured included respiratory muscle strength, pulmonary function tests, the Biering-Sorensen Test (BST), the Anterior Plank Test (APT), and the Y-Balance Test (YBT). Results indicated statistically significant improvements in the FIMT group for maximal inspiratory pressure, maximal expiratory pressure, forced vital capacity, and FEV 1 values ( p < 0.05). However, there were no significant differences between the groups in BST, APT, and YBT results ( p > 0.05). Overall, FIMT proved more effective than CST in enhancing respiratory muscle strength and lung volumes in football players, while both methods similarly affected trunk muscular endurance and dynamic balance.

10 Exploring sport friendship quality profiles in football participation among Chinese adolescents: a latent profile analysis

Reference: Front Psychol. 2026 Apr 24:17:1792610. doi: 10.3389/fpsyg.2026.1792610. eCollection 2026.
Authors: Qinghua Wu, Ying Zhao, Jieyou Zhou
Download link: https://pmc.ncbi.nlm.nih.gov/articles/PMC13154861/pdf/fpsyg-17-1792610.pdf
Summary: Football benefits adolescents‘ physical and mental health, but participation rates in China remain low despite government efforts. Few scholars have studied peer relationship differences as potential influences on football participation. This study investigated how sport friendship quality profiles relate to football participation and gender among adolescents. We recruited 450 adolescents (M age = 12.46 years, SD = 1.78; range = 8-16 years; male = 214, female = 236) and used the Sport Friendship Quality Scale (SFQS) to measure six dimensions of peer relationships. Latent Profile Analysis (LPA) was employed to identify subgroups based on friendship quality. The BCH method was then used to test differences in football participation across profiles, and ANOVA was used to examine gender differences. LPA revealed three distinct friendship quality profiles: a High-Need Group (16.6%) with low scores across all dimensions, and two other profiles characterized by consistently high scores (53.8%) and moderate but uneven scores (29.6%). Football participation differed significantly across profiles (χ2 = 17.22, df = 2, p < 0.001), with the High-Need Group showing the lowest engagement, followed by the moderate-score group, and the high-score group showing the highest level of participation. Friendship quality profiles and gender are associated with adolescent football participation. Findings highlight the need for targeted social interventions, particularly for the High-Need Group, and gender-specific strategies to support female engagement.

11 „It was clear from his childhood that he was destined to be a top striker“: investigating the construction of football talent narratives in the Italian sporting press

Reference: Front Psychol. 2026 Apr 24:17:1817389. doi: 10.3389/fpsyg.2026.1817389. eCollection 2026.
Authors: Gabriele Morganti, Thomas Blackwood, Alexandra Lascu, Francesca Strassoldo di Villanova, Elvira Padua, Bruno Ruscello, Adam L Kelly
Download link: https://pmc.ncbi.nlm.nih.gov/articles/PMC13152823/pdf/fpsyg-17-1817389.pdf
Summary: In this study, we adopted an interpretivist perspective to explore the construction of football talent narratives in the Italian sporting press. We aimed to understand distal influences on the recognition of beliefs and practices related to talent identification, selection, and development in Italian football. To achieve this, we conducted inductive content analysis on 26 articles from La Gazzetta dello Sport and interpreted the findings through the Skilled Intentionality Framework. Findings revealed that football talent narratives were constructed to emphasize: (a) the early steps (i.e., early start and father as mentor and gateway to early participation, early selection and specialization), (b) developmental pathways and career trajectories (i.e., early achievements and performance progression, playing up, and early exposure to senior-level football), (c) the attributes (i.e., body proportions and physical attributes, technical and tactical skills, and psychological characteristics), and (d) socially mediated validation (i.e., public recognition and market value and youth international selection). We argue that the Italian sporting press uses its narratives not only to describe talent but also to prescribe particular ways of becoming talented, thereby guiding the intentionality of players, parents, practitioners, and other stakeholders navigating the Italian football ecosystem. In line with this, our study contributes to the ongoing discussions about refining conceptualizations of talent identification and development as complex and socially constructed processes, encouraging sporting systems to reflect on the wider sociocultural context in which they operate, to investigate and refine their current practices and outcomes from an ecological perspective.

12 Knowledge of sport-related concussion among referees in youth football in Croatia, Germany, Norway, and Türkiye – a survey-based study

Reference: J Sci Med Sport. 2026 Apr 28:S1440-2440(26)00148-9. doi: 10.1016/j.jsams.2026.04.009. Online ahead of print.
Authors: Giulia Gorgoni, Gabriel Monthuley, Thor Einar Andersen, Nora Kümmeth-Gangel, Ivana Pavlinac, Zoran Dogas, Anna Nordström
Download link: https://www.jsams.org/action/showPdf?pii=S1440-2440%2826%2900148-9
Summary: Sport-related concussions (SRCs), though common in football, remain under-recognized, particularly at youth and amateur levels where medical personnel are rarely present. Referees are key stakeholders in safeguarding player health, yet their knowledge and awareness of SRCs are underexplored. This study assessed referees‘ knowledge and awareness about SRCs across Europe. A 19-item questionnaire was distributed by national football associations in Croatia, Germany, Norway, and Türkiye. Items addressed demographics, concussion knowledge, symptom recognition, awareness of assessment tools, and interest in education. A concussion knowledge score (CKS) was calculated. Data were analyzed using Kruskal-Wallis and Wilcoxon rank-sum test, with significance set at p < 0.05. 2722 surveys were analyzed. The overall median CKS was 75% with no significant differences between countries (p = 0.345). In Germany, CKS differed by gender and prior SRC history (significant differences, p < 0.01). Commonly recognized symptoms included dizziness (≥90%) and headache (≥78%), whereas subtler signs like irritability (≤21%) were poorly identified. Eleven percent of referees reported awareness of SRC assessment tools, most citing eye movement tests; only few named formal tools such as Sport Concussion Assessment Tool (SCAT) or Concussion Recognition Tool (CRT). Across all respondents, 73% expressed interest in concussion education. Referees demonstrated moderate SRC knowledge but notable gaps in recognizing subtle symptoms and awareness of validated assessment tools. Due to the highly uneven sample distribution, between-country comparisons are exploratory. Incorporating concussion education into referee licensing may enhance early identification and promote player safety in youth and amateur football.

13 Return-to-play timing and secondary anterior cruciate ligament injury risk in elite soccer players: A transfermarkt-based longitudinal analysis

Reference: J Exp Orthop. 2026 May 19:13:e70763. doi: 10.1002/jeo2.70763. eCollection 2026 Apr.
Authors: Riccardo D’Ambrosi, Andy Williams, Bertrand Sonnery-Cottet, Christian Fink, Philipp Baumert
Download link: https://esskajournals.onlinelibrary.wiley.com/doi/epdf/10.1002/jeo2.70763
Summary: Anterior cruciate ligament (ACL) injuries are frequent and potentially career-threatening in elite soccer. The optimal timing for return-to-play (RTP) remains debated, particularly its association with secondary ACL injury. This study evaluated temporal trends in RTP duration and investigated the association between RTP duration, post-ACL match exposure and secondary ACL injury risk in professional male soccer players. Longitudinal publicly available data were analysed from Transfermarkt (2005-2020) on ACL injuries in elite male soccer players from Germany, France, Italy, Spain and the United Kingdom. Players were grouped into three five-season periods. Multivariable logistic regression was used to examine the association between RTP duration (days) and secondary ACL injury risk, adjusting for time period, post-ACL match exposure (per 1000 min) and age. Secondary ACL injury proportions and RTP duration trends were compared across time periods. A total of 1011 ACL injuries were identified in 862 unique players; 15.5% (n = 134) sustained ≥2 ACL injuries. Mean RTP duration increased over time (196.7 ± 50.9 days in 2005-2010 vs. 219.9 ± 67.4 days in 2015-2020; p < 0.001). The proportion sustaining a secondary ACL injury increased from 9.0% to 16.4% (p = 0.031). Post-ACL match exposure was strongly associated with reinjury risk (OR: 1.39 per 1000 min, p < 0.001), and younger age was independently associated with higher risk (OR: 0.86 per year, p < 0.001). After adjustment, players in 2010-2020 still exhibited a > 2-fold higher reinjury risk compared with 2005-2010 (p < 0.05). Longer RTP duration was not protective and showed a small positive association with reinjury risk (OR: 1.004, p = 0.034). Although RTP duration has increased over the past 15 years in elite soccer, this has not reduced secondary ACL injury risk. Extending RTP duration alone does not appear to reduce reinjury risk.

14 Secondary Muscle Injuries and Performance Decline After Anterior Cruciate Ligament Reconstruction in Professional Soccer: A Retrospective Matched Cohort Study

Reference: Am J Sports Med. 2026 May 19:3635465261441252. doi: 10.1177/03635465261441252. Online ahead of print.
Authors: Daniele Mazza, Angelo De Carli, Francesco De Carli, Salvatore Gagliardo, Francesco Suraci, Giorgio Liberati Petrucci, Vincenzo Santoriello, Paolo Zeppilli
Summary: Professional soccer players who return to play after anterior cruciate ligament reconstruction (ACLR) often experience secondary muscle injuries, but the true incidence, timing, and contributing factors remain incompletely defined. It was hypothesized that soccer players returning after ACLR would show a higher incidence of secondary muscle injuries than matched controls, with an increased risk associated with premature return to play (RTP). The purpose of this study was to identify the incidence and risk factors for muscle injuries after ACLR and to evaluate their impact on athletic performance. A total of 40 professional male soccer players who underwent ACLR between 2020 and 2023 were followed for 24 months after RTP. Players were matched 1:1 to controls based on age, position, league, and preinjury minutes played. Collected variables included RTP timing, muscle injury incidence and timing, injury characteristics, performance metrics (minutes played, goals/assists, defensive actions), and market value changes. Analyses included paired t tests, multivariable logistic regression, Kaplan-Meier survival curves, and Cox proportional hazards modeling. Within 12 months of RTP, 13 of 40 players (32.5%) in the ACLR group sustained at least one secondary muscle injury compared with 5 of 40 players (12.5%) in the control group (incidence rate ratio, 2.60; P < .001). The injury risk peaked between 3 and 6 months after RTP. RTP in <9 months was a strong independent predictor of a secondary muscle injury (adjusted odds ratio, 4.85 [95% CI, 2.12-11.07]). Professional soccer players returning to play after ACLR face a substantially elevated risk of secondary muscle injuries, particularly within the first 3 to 6 months. Premature RTP is a key modifiable risk factor.

15 The Antioxidant Paradox in Soccer: Striking the Balance between Protection and Performance

Reference: Comb Chem High Throughput Screen. 2026 May 12. doi: 10.2174/0113862073442299260217110531. Online ahead of print.
Authors: Manaf AlMatar, Fatma Hassan Abd Elbasset Mourgan, Eman Abdelhalim Mohamed Ali, Nana ELDawy Ahmed Hefny, Wafaa Mohmoud Abdellatif Bekir
Summary: Antioxidants are also taken by athletes to facilitate recovery and performance, especially by soccer players, given their high-level physical activity, which has been reported to produce ROS that contribute to the severity of muscle injury and fatigue. However, ROS also act as signaling mediators, crucial for muscle adaptation and mitochondrial function. The recent study aims to discuss the potential dual role of antioxidant intake in soccer, emphasizing that chronic intake can inhibit adaptations via ROS signaling, whereas acute intake can be useful for athletes, especially during periods with congested fixtures. The study involves the role of vitamin C and vitamin E, Coenzyme Q10 (CoQ10), Docosahexaenoic Acid (DHA), polyphenols, as well as other commonly supplemented antioxidants with further explanation on the potential role of the time, dosage, and duration associated with recovery, findings showing potential enhanced recovery for soccer players following intake but with high dosage potentially associated with inhibited adaptations. Recommendations for soccer players, specifically coaches, relate to the appropriate timing of antioxidant supplementation to prevent inhibited adaptations following permissible levels of use during training.

16 Amateur Soccer Heading and Acute Elevations in Blood-Based p-Tau217 and S100B

Reference: JAMA Neurol. 2026 May 18:e261224. doi: 10.1001/jamaneurol.2026.1224. Online ahead of print.
Authors: Marloes I Hoppen, Marsh Königs, Charlotte E Teunissen, Inge M W Verberk, Jos Twisk, Jaap Oosterlaan, Everard G B Vijverberg
Summary: Former professional soccer players have increased risk of neurodegenerative disease, potentially due to cumulative exposure to repetitive head impacts such as heading. However, the acute effects of heading on neural integrity remain unclear. The aim was to assess the acute association of real-life heading with blood biomarkers of neural damage before and after soccer matches. In this prospective population-based case-control study, soccer players participated in organized matches (August-December 2024). Blood samples were collected prematch and immediately and delayed postmatch (<1 and 24-48 hours, respectively). Video analysis quantified heading exposure, including frequency and intensity. Exercise intensity was monitored using local position monitoring and heart rate analysis. Players from higher-level amateur soccer competitions were recruited through communication channels of the Royal Dutch Football Association and screened for eligibility. Inclusion criteria included the following: male sex, age older than 18 years, and no history of a neurological condition.Real-life heading exposure during a single amateur soccer match. Blood biomarkers of neural damage were measured and included the following: phosphorylated tau 217 (p-tau217), brain-derived tau (BD-tau), neurofilament light chain (NfL), glial fibrillary acidic protein (GFAP), S100B calcium-binding protein (S100B), and neuron-specific enolase (NSE). The main outcome was the association between heading exposure and change in biomarker concentration, assessed with linear mixed models while correcting for exercise intensity. A total of 389 soccer players were screened for eligibility. Among the 302 players participating in 1 of the 11 matches (mean [SD] age, 24.6 [5.2] years), 216 (72%) had heading exposure. Mean (SD) exposure was 2.0 (2.1) headers per player per match, and 48% of players had high-impact heading exposure (ball trajectories >20 m; 80 players [26%] with exposure to a single high-impact header; 65 players [22%] with exposure to multiple high-impact headers). Players exposed to heading showed significantly greater immediate postmatch increases in S100B concentration (n = 299, P = .03; Cohen d = 0.29) compared with unexposed players. Exposure to more headers was associated with greater increases in S100B (n = 299, P = .02; Cohen d = 0.07 per header) and p-tau217 concentration (n = 296, P = .01; Cohen d = 0.09 per header). High-impact headers were also associated with greater increases in p-tau217 (n = 148, P = .03; Cohen d = 0.40) and S100B concentration (n = 149, P = .02; Cohen d = 0.43) compared with no exposure. Observed biomarker elevations normalized within 24 to 48 hours. No other significant associations were found. Results were robust to sensitivity analysis adjusting for blood volume. Findings of this case-control study show that soccer heading was associated with acute increases in blood biomarkers of neural damage, including dose-response relationships. These findings suggest that amateur-level heading may acutely affect neural integrity.

17 Evaluation of using the SOCcer automated occupation auto-coding algorithm to assist expert coding of job descriptions

Reference: Ann Work Expo Health. 2026 May 12;70(4):wxag031. doi: 10.1093/annweh/wxag031.
Authors: Pabitra R Josse, Daniel E Russ, Leila Orszag, Cheryl E Peters, Grace Shen-Tu, Jennifer E Vena, Melissa C Friesen
Download link: https://pmc.ncbi.nlm.nih.gov/articles/PMC13181392/pdf/wxag031.pdf
Summary: Systems to automatically code job descriptions to standardized occupations, such as SOCcer, reduce the burden of expert coding in occupational studies, but expert coding remains needed. We evaluated how frequently experts select a SOCcer-suggested code when using the SOCAssign platform, which shows SOCcer’s top 10 scoring codes (Si, with i denoting results ranking, compared to independent coding). We evaluated 2 protocols for SOCcer-assisted coding using the SOCAssign platform that we undertook when we had insufficient resources to employ the best practice of independent double-coding, with discordances resolved by consensus. Protocol 1 used a single coder, with a supervisor providing additional review for a subset based on features we identified that were more likely to indicate potential discordance between coders. Protocol 2 allocated jobs to be coded by 1 or 2 coders based on the SOCcer score (the probability an expert would have selected that code) for the highest scoring code (S1 score) and the score difference between the top 2 scoring codes. For comparison purposes, we included a third set of jobs that had previously undergone independent expert coding. For each job, we identified if the expert selected the top-scoring (S1) code, or one of the top 3 (S1-3) or top 10 (S1-10) scoring codes from SOCcer and compared findings across coding protocols, overall and by S1 score. In Protocol 1, 25% of 6,824 jobs underwent supervisory review. In Protocol 2, jobs with an S1 score <0.2 or S1 – S2 score difference of <0.2 underwent coding by 2 experts (45% of 7,381 jobs); the remainder were coded by one expert. In both protocols and in independent coding, experts selected S1, one of S1-3 or one of S1-10 with similar prevalences (48% to 50%, 62% to 64%, and 73% to 74%, respectively). Expert coders were more likely to deviate from the SOCcer-suggested list for jobs with low score/score differences (39% to 44%) than high score/score differences (11% to 13%). In all evaluations, the frequency of selecting a SOCcer-suggested code increased with score, with some attenuation observed when the S1 – S2 score difference was <0.2. Our evaluations provide support for SOCcer-assisted expert coding. We provide recommendations for identifying jobs where multiple reviewers may be most needed.

18 Comparisons of kinanthropometric variables and physical performance in adolescent soccer players of different biological maturation

Reference: PeerJ. 2026 May 13:14:e21203. doi: 10.7717/peerj.21203. eCollection 2026.
Authors: Rou Wang, Meng Liu, Frank Nugent et al.
Download link: https://pmc.ncbi.nlm.nih.gov/articles/PMC13179742/pdf/peerj-14-21203.pdf
Summary: Biological maturation is a crucial factor in the physical development of adolescent soccer players, affecting key performance-related variables essential for talent development. This study investigated differences across maturation stages in kinanthropometric and physical performance parameters in young male soccer players. Forty-three players (13.26 ± 1.03 years) were classified into pre-, circa-, and post-peak height velocity (PHV) groups, with maturation status assessed using a validated AI-based method (China-05). Participants then completed a series of kinanthropometric assessments, including height, body mass, and body composition measured via dual-energy X-ray absorptiometry (DEXA). Additionally, they performed physical performance tests, which consisted of the countermovement jump (CMJ), isometric mid-thigh pull (IMTP), maximal oxygen uptake (VO2max) test, Wingate anaerobic test (WAT), 10-meter and 30-meter sprint times, and the Yo-Yo intermittent recovery test (Yo-Yo IR1). Results showed significant differences in fat mass and skeletal muscle mass, particularly between post- and pre-PHV players (p < 0.001), with post-PHV players exhibiting higher skeletal muscle mass. In terms of performance, the post-PHV group recorded significantly lower VO2max (p < 0.05) but higher CMJ heights (p < 0.001), while sprint times showed no significant variation across maturity stages (p > 0.05). Fatigue index and peak force also differed notably, with post-PHV players displaying higher fatigue levels and peak force (p < 0.001). Significant differences in IMTP impulse at 100 ms and 300 ms (p < 0.001) indicated greater strength and power with advanced maturation. These findings underscore the influence of biological maturation on kinanthropometric and physical performance metrics, linking advanced maturation with increased strength and power but reduced aerobic capacity in post-PHV players, likely due to greater body mass. The results highlight the need for tailored training programs that consider both chronological and biological age to optimize player development, supporting more effective talent identification and training strategies.

19 Position-Dependent External Load Management in Professional Football: An Exploratory Observational Study on the Effects of Microcycle Length

Reference: J Strength Cond Res. 2026 May 27. doi: 10.1519/JSC.0000000000005429. Online ahead of print.
Authors: Carlos Galiano, Fábio Yuzo Nakamura, João Ribeiro, Iván Asín-Izquierdo, Jose Antonio Asian-Clemente
Summary: The literature shows that professional football players face different external loads during matches based on their playing positions, but it remains unclear whether their weekly accumulated load reflects their specific roles or remains consistent regardless of position. The objectives of this study were to analyze how microcycle length affects the external load ratio across different playing positions in professional football players, and to examine differences in the ratio values depending on players‘ specific positions and microcycle length. Global Positioning System-based metrics from a professional football club were collected for 2 consecutive seasons, covering a total of 92 matches (68 regular season, 12 European competitions, and 12 national cup). The external load ratio was defined as the accumulated load in the microcycle/match load in competition. The results of the study show that, in most cases, longer microcycles are associated with higher external load ratios across all playing positions and variables analyzed (p < 0.001). However, except for total distance, all external load variables showed similar ratios between 3-day and 4-day microcycles. Furthermore, the ratios between positions remained similar across all playing positions and microcycle lengths evaluated, except for high decelerations in 3- and 6-day microcycles (p < 0.040) and high accelerations in 3-day microcycles (p < 0.001). In conclusion, longer microcycles increase external load ratios across all playing positions, with training loads generally aligned with match demands regardless of position or microcycle length. Effective load monitoring and individualization are essential to optimize performance and reduce injury risk in professional football.

20 Examining the relationship between gamification profiles (HEXAD) and mental fatigue in football players: a theoretical and contextual analysis

Reference: BMC Psychol. 2026 May 21. doi: 10.1186/s40359-026-04828-4. Online ahead of print.
Authors: Mehmet Kara, Fatma Cepikkurt, Murat Genc, Huseyin Gumus, Mustafa Can Koc, Dessalegn Wase Mola, Bekir Yalman
Download link: https://link.springer.com/content/pdf/10.1186/s40359-026-04828-4_reference.pdf
Summary: Human behavior in performance settings reflects the interplay of cognitive and psychological processes. This study examined the associations between gamification user types and mental fatigue scores in male football (soccer) players and investigated the interactive effects of playing position, competition level, and serious injury experience. A total of 331 male football players actively competing in different cities across Turkey participated in this cross-sectional, correlational study. Data were collected via the Mental Fatigue Awareness Scale in Athletes (MFASA) and the Modified Gamification User Types Scale (MGUTS). Analyses included Pearson correlation and two-factor analysis of variance (ANOVA). The MGUTS total score was negatively associated with mental fatigue (r = – .17, p < .01). Mental fatigue scores differed significantly as a function of the playing position × serious injury experience interaction (F(3, 323) = 12.38, p < .001, η² = 0.103) and the playing position × competition level interaction (F(3, 323) = 20.69, p < .001, η² = 0.161). The interaction effects were most pronounced particularly in the goalkeeper and defender positions. Mental fatigue in football players operates as a multidimensional construct shaped not only by physical loading but by the joint influence of motivational profiles, position-specific cognitive demands, and experience-level factors. The findings highlight the importance of differentiating mental fatigue assessment and intervention approaches on the basis of positional role and competition level.

21 Hip Joint Loading During Walking Is Associated With Cartilage Defect Severity in Young Adult Football Players With Hip/Groin Pain

Reference: J Orthop Res. 2026 May;44(5):e70219. doi: 10.1002/jor.70219.
Authors: Kay M Crossley, Yi-Chung Lin, Anthony G Schache et al.
Download link: https://pmc.ncbi.nlm.nih.gov/articles/PMC13179577/pdf/JOR-44-0.pdf
Summary: Understanding factors associated with early hip osteoarthritis (OA) in young active adults may facilitate hip OA prevention. We investigated the cross-sectional association between hip contact force (HCF) during walking and cartilage defect severity, accounting for cam morphology size (alpha angle), hip pain severity, sex, age, and walking speed, in football players with hip/groin pain. One hundred and twenty-one football players (18-50 years; 26 women) with > 6-month hip/groin pain and no radiographic OA underwent MRI and a Dunn 45° radiograph. Outcome: Scoring Hip Osteoarthritis with MRI (SHOMRI) score for cartilage defect severity (0-20), categorized into three SHOMRI groups: (a) SHOMRI = 0; (b) SHOMRI = 1-3; and (c) SHOMRI = 4+. Movement and ground force data were captured whilst participants walked at their self-selected pace. Musculoskeletal modeling was used to calculate HCF for one stride cycle. The exposure variable was HCF impulse (body weight times seconds [BW.s]). Differences in HCF impulse based on SHOMRI group (for the most symptomatic hip) were assessed using linear models, controlling for alpha angle, sex, age, walking speed, hip pain, and contralateral hip pain status. Resultant HCF impulse was significantly higher for participants in the 0 versus 4+ SHOMRI group (mean difference; 95%CI: 0.142BW.s; 0.028-0.256 for swing and 0.106BW.s; 0.029-0.184 for stance) and 0 versus 1-3 SHOMRI group (0.071 BW.s; 0.016-0.125 for swing). Participants with more severe cartilage defects walked with lower hip joint loading, and other variables (e.g., alpha angle size, hip pain severity, age) contributed little to this relationship. Hip joint under-loading could be a possible target for hip OA prevention.