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 Influence of Training Load on Recovery, Wellness, and Performance in Elite Soccer Athletes
Reference: Int J Sports Physiol Perform. 2026 Aug 26:1-8. doi: 10.1123/ijspp.2026-0076. Online ahead of print.
Authors: Sam R Moore, Elena I Cantú, Abbie E Smith-Ryan
Summary: Athlete monitoring has emerged as a common method to track athlete status and adjust training for optimal performance. Despite the influx of monitoring-related resources at the collegiate level, actual training load modifications are largely anecdotal. This prospective cohort study investigated relationships between previous day training load, objective nightly recovery, and next-day subjective wellness and max speed (MS) in elite soccer athletes across a collegiate season. Twenty-six collegiate female soccer athletes were tracked across the duration of their season (2024-2025) for training load (wearable global positioning systems monitors), objective nightly recovery (wearable recovery rings), next-day subjective wellness (morning wellness survey), and MS performance. Previous day training load measures of distance and high-speed running were significant predictors of variables related to nightly objective sleep recovery, next day subjective readiness, and next day speed performance. High-speed running models consistently performed better than total distance for predicting changes in recovery, wellness, and MS. Numerous associations between previous day training load and objective and subjective measures increase accessibility of female athlete monitoring methods for applied practitioners. Although the magnitudes of coefficients vary, the consistency of significant findings across monitoring methods provides utility for continuous and comprehensive athlete monitoring, demonstrating the importance of subjective readiness measures beyond traditional performance metrics, while also addressing the paucity of literature in elite female athletes.
#2 Sport-Specific Athletic Adaptation: What Can We Learn From Elite Soccer Players?
Reference: JACC Adv. 2026 Aug;5(8):103002. doi: 10.1016/j.jacadv.2026.103002.
Authors: Prashant Rao, Connor Riegal
Download link: https://www.jacc.org/doi/epdf/10.1016/j.jacadv.2026.103002
#3 Multivariate Neuromuscular Profile and Principal Component Analysis: A Pilot Study in Professional Female Soccer Players
Reference: Life (Basel). 2026 Jul 28;16(8):1248. doi: 10.3390/life16081248.
Authors: Luis Romero-Vera, David Ulloa-Díaz, Jonathan Concha-Poblete, Misael Sandoval-Cárcamo, Claudio Carvajal-Parodi, Francisco Guede-Rojas, Carlos Jorquera-Aguilera, Cristobal Ulloa-Barboza, Claudio Hernández-Mosqueira, Gustavo Pavez-Adasme, Eduardo Guzmán-Muñoz, Héctor Fuentes-Barría, Jorge Leschot-Gatica
Download link: https://www.mdpi.com/2075-1729/16/8/1248
Summary: Professional women’s football requires precise neuromuscular characterisation because of the high mechanical demands associated with acceleration, deceleration, jumping, braking, landing, and rapid force production. The aim was to characterise the multivariate neuromuscular profile derived from the countermovement jump (CMJ) and isometric mid-thigh pull (IMTP), and to examine neuromuscular components according to tactical positions in professional female football players. Twenty-three professional female football players were assessed using the CMJ and IMTP. Force-time, impulse, rate of force development, jump performance, landing, and inter-limb imbalance variables were extracted. Principal component analysis (PCA) was applied to the standardised variables, and individual component scores were compared according to tactical positions using one-way analysis of variance (ANOVA). The first five principal components explained 79.19% of the total variance. PC1 represented the propulsive force and the rate of force development; PC2 reflected total force and mechanical impulse; PC3 represented early explosiveness; PC4 grouped indicators of inter-limb imbalance; and PC5 integrated jump performance and landing control. No statistically significant differences were observed between tactical positions. The combination of CMJ, IMTP, and PCA enabled multiple muscle-force variables to be synthesised into interpretable neuromuscular dimensions. The findings provide preliminary and exploratory evidence to support the individual monitoring of female football players. Given the low participant-to-variable ratio, the PCA findings should be considered exploratory.
#4 Comparison of Anthropometric Equations to Estimate Body Composition in Chilean Male Adolescent Soccer Players
Reference: J Funct Morphol Kinesiol. 2026 Aug 22;11(3):326. doi: 10.3390/jfmk11030326.
Authors: Álvaro Farfán-Díaz, Miguel Alarcón-Rivera, Marcelo Andrade Oyarzun, Daniel Tapia-Villanueva, Exal Garcia-Carrillo, Iván Molina-Márquez, Rodrigo Yáñez-Sepúlveda, Dario Barrera-González, Felipe Montalva-Valenzuela
Download link: https://www.mdpi.com/2411-5142/11/3/326
Summary: Anthropometric body-composition assessment in youth soccer commonly relies on equations developed in different source populations and based on distinct body-composition models, potentially altering nutritional and sport-related interpretation. This study compared body-fat estimates from equations intended to report the same outcome, body fat percentage, but based on different operational models, and quantified muscle-mass outputs from anthropometric approaches targeting total-body skeletal, whole-body, and tissue-level muscle compartments in a cohort of Chilean male U-15 and U-16 players. This secondary cross-sectional method-comparison study analyzed anonymized anthropometric records collected in 2018 from 50 male players. Slaughter, Faulkner, Carter, Deurenberg, and Sloan-Siri estimates of body fat were compared, together with Poortmans, Lee, Doupe, and Kerr muscle-mass approaches. Absolute agreement among adiposity equations was evaluated using a two-way random-effects, absolute-agreement, single-measure ICC [ICC(A,1)] and Bland-Altman analyses. Muscle-mass approaches were compared with repeated-measures analysis; pairwise difference-versus-mean summaries across different muscle constructs were interpreted descriptively rather than as formal agreement tests. Sensitivity analyses excluded Deurenberg and examined a maturation-related Slaughter scenario. Deurenberg yielded the highest body-fat estimate (18.97 ± 3.07%), followed by Slaughter (13.32 ± 3.35%), Faulkner (10.84 ± 1.40%), Sloan-Siri (8.01 ± 2.80%), and Carter (7.91 ± 1.49%). Global differences were large (χ2(4) = 182.96; p < 0.001; Kendall’s W = 0.915), and individual absolute agreement was low [ICC(A,1) = 0.157; bootstrap 95% CI 0.102-0.212]. Excluding Deurenberg did not remove the between-method differences (χ2(3) = 124.44; p < 0.001; W = 0.830). For muscle mass, mean estimates ranged from 25.11 ± 3.07 kg with Poortmans to 31.26 ± 4.94 kg with Doupe, with a significant method effect after Greenhouse-Geisser correction (p < 0.001). The adiposity equations yielded substantially different numerical estimates of the same reported outcome, body fat percentage, and showed low individual-level absolute agreement. Muscle-mass approaches also produced large numerical differences, partly expected because they target different compartments. Outputs from different equations or constructs should not be treated as numerically interchangeable. Because no criterion reference method was included, this study quantifies method dependence rather than validity and cannot identify the most accurate equation.
#5 Training Sequence Matters: Neuromuscular Training Followed by Small-Sided Games Enhances Physical Fitness and Soccer-Specific Performance in Prepubertal Soccer Players
Reference: J Funct Morphol Kinesiol. 2026 Aug 16;11(3):319. doi: 10.3390/jfmk11030319.
Authors: Sofiene Bouguerra, Mohamed Amine Selmi, Lotfi Bouguerra, Yassine Negra, Roland van den Tillaar, Raouf Hammami
Download link: https://www.mdpi.com/2411-5142/11/3/319
Summary: Physical and technical development in youth soccer depends on the integration of neuromuscular and small-sided games (SSG) training. However, the influence of training sequence on adaptations remains unclear in prepubertal players. Therefore, this study aimed to compare the effects of performing neuromuscular training before or after SSG on physical fitness and soccer-specific performance in trained prepubertal soccer players. Twenty-two trained prepubertal male soccer players were randomly assigned to either neuromuscular training followed by SSG or SSG followed by neuromuscular training. Both groups completed a 6-week in-season intervention, including two weekly sessions, with each group performing 3 weeks of neuromuscular training and 3 weeks of SSG training in a different order. Physical fitness (back extensor strength, five-jump test, 10 m sprint, and Yo-Yo IR1) and soccer-specific performance (change of direction with ball and Loughborough Soccer Passing Test) were assessed before and after the intervention. All 22 participants completed the intervention (n = 11 per group). Both groups demonstrated significant improvements over time in most physical fitness and soccer-specific performance variables (p < 0.01). However, significant group × time interactions indicated that the magnitude of improvement was consistently greater when neuromuscular training preceded small-sided games (p ≤ 0.041). Compared with the SSG-before-neuromuscular group, the neuromuscular-before-SSG group achieved larger improvements in back strength (+9.8% vs. +2.7%), five-jump test (+17.1% vs. +10.0%), 10 m sprint (-10.3% vs. -6.3%), Yo-Yo IR1 distance (+35.4% vs. +20.4%), change of direction with ball (-7.4% vs. -1.0%), and Loughborough Soccer Passing Test (-16.0% vs. -7.8%). Training sequence may influence the magnitude of short-term adaptations in prepubertal soccer players. Although both training orders improved performance, performing neuromuscular training before SSG resulted in greater improvements in several physical fitness and soccer-specific performance outcomes. These findings suggest that training order may represent an important factor in youth soccer training design; however, further research is required to confirm the consistency of this sequencing effect and to explore the mechanisms underlying these adaptations.
#6 Association Between Change-of-Direction Performance and Landing Impact Characteristics During a Single-Leg Forward Drop Jump Landing Task in Junior Soccer Players
Reference: J Funct Morphol Kinesiol. 2026 Aug 10;11(3):312. doi: 10.3390/jfmk11030312.
Authors: Shinya Kishi, Yuuji Kimura, Takao Minami
Download link: https://www.mdpi.com/2411-5142/11/3/312
Summary: Efficient landing shock attenuation is important for both athletic performance and lower-extremity injury prevention in youth soccer players. Although landing biomechanics and change-of-direction (COD) performance have been widely investigated, the relationship between field-based COD performance and landing impact characteristics remains unclear. This study aimed to examine the relationships between linear sprint performance, COD performance, and landing impact during a standardized single-leg forward drop jump landing task in junior soccer players. Thirty-six junior soccer players (22 boys and 14 girls; 10-12 years) participated in this cross-sectional study. Linear sprint performance and COD performance were assessed using a 30 m sprint test and a 30 m zigzag run test, respectively. Landing impact was evaluated during a standardized single-leg forward drop jump landing task using a force plate. Body weight-normalized peak vertical ground reaction force (peak vGRF, %BW) was calculated for each trial, and the average of the final five successful trials was used for analysis. Relationships between performance measures and body weight-normalized peak vGRF were examined using Spearman’s rank correlation coefficients and partial Spearman correlation analyses adjusted for sex. No significant correlation was observed between 30 m sprint performance and body weight-normalized peak vGRF (ρ = 0.106, p = 0.537). In contrast, 30 m zigzag run performance showed a moderate positive correlation with body weight-normalized peak vGRF (ρ = 0.401, p = 0.015), indicating that poorer COD performance was associated with greater landing impact. This association remained significant after adjustment for sex (partial ρ = 0.474, p = 0.004). These findings suggest that landing impact characteristics may represent one biomechanical factor associated with COD performance. Although the observed association was moderate, field-based COD assessments may provide practical information regarding landing impact characteristics. Future studies should incorporate biological maturation, COD deficit, and additional biomechanical variables to further clarify these relationships.
#7 Pre-Season Changes in Physical Performance and Early Competitive Squad Inclusion in Under-15 Male Soccer Players
Reference: J Funct Morphol Kinesiol. 2026 Jul 29;11(3):300. doi: 10.3390/jfmk11030300.
Authors: Artur Avelino Birk Preissler, Filipe Manuel Clemente, Júlio Brugnara Mello, Ana Filipa Silva, Rui Miguel Silva, Pedro Schons
Download link: https://www.mdpi.com/2411-5142/11/3/300
Summary: Pre-season physical monitoring may help coaches understand short-term changes in youth soccer players and examine whether physical indicators are associated with early squad inclusion. This study aimed to analyze changes in physical performance during the pre-season period and to examine whether pre- and post-assessment physical performance differed between squad-included and non-included under-15 male soccer players in the first five official matches of the main competition. Thirty-seven male outfield players were assessed using the Squat Jump (SJ), Countermovement Jump (CMJ), 20 m linear sprint (Sprint-20 m), 20 m change-in-direction test (COD-20m), and Yo-Yo Intermittent Recovery Test Level 1 (Yo-Yo IRL1). Squad-included players were those listed in at least one of the first five official match reports, whereas non-included players were not listed in these reports but remained part of the broader under-15 program. Significant increases were observed in SJ (+1.44 cm, p = 0.007), CMJ (+1.36 cm, p = 0.006), and COD-20m (+0.38 km·h-1, p = 0.002), whereas Sprint-20 m and Yo-Yo IRL1 did not change significantly. Fourteen players were squad-included and 23 were non-included. Squad-included players presented higher pre-assessment values for SJ, CMJ, COD-20m, and the exploratory composite physical score, and higher post-assessment values for SJ, CMJ, Sprint-20 m, COD-20m, and the exploratory composite physical score. The largest between-group difference was observed for post-assessment COD-20m (14.19 ± 0.49 vs. 13.40 ± 0.74 km·h-1, p < 0.001, d = 1.25). Early squad inclusion was associated with higher absolute physical performance, particularly post-assessment COD-20m, whereas the magnitude of pre-to-post changes was not clearly associated with squad inclusion.
#8 An evaluation of dietary practices of soccer players from an English Premier League team using a behavioural change science framework
Reference: J Sports Sci. 2026 Aug 26:1-20. doi: 10.1080/02640414.2026.2722778. Online ahead of print.
Authors: Wee Lun Foo, Graeme L Close, José L Areta, James P Morton
Download link: https://www.tandfonline.com/doi/epdf/10.1080/02640414.2026.2722778?needAccess=true
Summary: Professional soccer players often fail to meet recommended dietary intakes. Accordingly, we aimed to quantify dietary intake of male English Premier League (EPL) players and explore the enablers and barriers influencing dietary behaviours using the Capability-Opportunity-Motivation and Behaviour (COM-B) model. Ten players from a single EPL club participated. Dietary intakes were assessed using the remote food photography method over a 4-day in-season period comprising a training day, the day before a match (MD-1), match day (MD), and the day after a match (MD + 1). On day 5, dietary recalls and semi-structured interviews were conducted to explore factors influencing dietary behaviours. Relative carbohydrate intake was significantly higher on MD-1 (4.6 ± 0.8 g·kg BM-1·day-1) than on training days (3.5 ± 0.8 g·kg BM-1·day-1, p = 0.019) and MD + 1 (3.6 ± 0.5 g·kg BM-1·day-1, p = 0.013). Knowledge (psychological capability) was the primary enabler of dietary behaviours. Key barriers included beliefs about consequences (reflective motivation), particularly the desire to feel light before and during matches and suppressed appetite post-match (automatic motivation). Reflective (desire to feel light) and automatic (suppressed appetite) motivation limited fuelling. Although knowledge supported dietary behaviours, targeted behaviour-change interventions beyond education are needed to improve carbohydrate intake.
#9 Artificial Intelligence and Psychophysiological Monitoring for Integrated Performance Modeling in Elite Soccer: A Scoping Review of Applications, Evidence Gaps, and Translational Challenges
Reference: Sports (Basel). 2026 Aug 19;14(8):360. doi: 10.3390/sports14080360.
Authors: Ismail Dergaa, Wissem Dhahbi, Mohamed Amine Dergaa, Mortadha Razzak, Halil İbrahim Ceylan, Valentina Stefanica, Raul Ioan Muntean, Noomen Guelmami
Download link: https://pmc.ncbi.nlm.nih.gov/articles/PMC13517148/pdf/sports-14-00360.pdf
Summary: Elite soccer performance emerges from the interplay of cognitive, emotional, psychophysiological, and tactical processes that operate in real time during matches. Advances in wearable sensors and artificial intelligence (AI) now allow continuous monitoring of physiological and psychological states. They also allow modeling of how these states relate to tactical and physical performance. Existing reviews have examined machine learning in soccer, heart rate variability (HRV) monitoring, and psychological determinants of performance separately. No scoping review has mapped the intersection of AI analytics, wearable psychophysiological monitoring, and psychological performance constructs as one integrated decision-support framework in elite soccer. The aim of this study was to map the available evidence on the integration of AI and machine learning with psychophysiological monitoring for performance modeling in elite soccer, to identify the psychological constructs already used as model inputs, to describe the wearable technologies and AI methods applied, and to set out the translational challenges and evidence gaps that need priority attention. The review followed the PRISMA extension for Scoping Reviews (PRISMA-ScR) and the updated Joanna Briggs Institute (JBI) methodology. The protocol was registered on the Open Science Framework (OSF). Six databases (PubMed/MEDLINE, Scopus, Web of Science, SPORTDiscus, IEEE Xplore, and PsycINFO) were searched from January 2000 to March 2026 using the Population-Concept-Context (PCC) framework. Two reviewers independently screened titles, abstracts, and full texts (Cohen’s kappa = 0.82). Thirty-six sources met the eligibility criteria after screening of 3104 records. AI and machine learning have been applied widely to predict physical and tactical performance in soccer, yet they rarely include psychological constructs. Reported models (decision trees, gradient boosting, and artificial neural networks) reach high accuracy for physical outcomes in internal validation, for example, above 66% for injury risk. Multi-modal models that add physiological and psychological inputs report stronger prediction. These figures come mostly from internal validation, and external validation and overfitting controls are seldom reported, so they should be read as optimistic upper bounds. Psychological and psychophysiological inputs remain under-represented. Explainable AI (XAI) methods, in particular Shapley Addictive exPlanations (SHAP) values, are appearing, but validation with domain experts is scarce. HRV has been reviewed as a psychophysiological marker in soccer, yet its use within AI decision-support tools for real-time psychological readiness has not been mapped. Three translational challenges stand out: the ecological validity gap between laboratory cognitive tests and match-embedded psychophysiology; the interpretability problem of opaque AI in high-stakes decisions; and the data fragmentation problem created by disconnected physical, tactical, and psychological data streams. Integrating AI with wearable psychophysiological monitoring offers a credible route toward integrated performance modeling in elite soccer. Closing this gap calls for multi-modal frameworks that combine psychological constructs, physiological markers, and tactical data within explainable AI. Research priorities include ecologically valid psychophysiological assessment protocols, position-specific psychological profiling, and practitioner-validated tools that turn AI outputs into usable coaching recommendations.
#10 Mapping Scientific Knowledge on Body Composition and Anthropometry in Soccer: A Bibliometric Analysis of the Last 35 Years (1990-2025)
Reference: Sports (Basel). 2026 Aug 12;14(8):349. doi: 10.3390/sports14080349.
Authors: Juan David Paucar-Uribe, Boryi A Becerra-Patiño, Aura D Montenegro-Bonilla, Armando Monterrosa-Quintero, Jorge Olivares-Arancibia, Daniel Rojas-Valverde, Rodrigo Yáñez-Sepúlveda, José Francisco López-Gil
Download link: https://pmc.ncbi.nlm.nih.gov/articles/PMC13517670/pdf/sports-14-00349.pdf
Summary: Anthropometric analysis has become a key tool for analyzing body composition to assess, monitor, and track structural changes in soccer players. The objective of this study was to analyze the scientific literature on body composition and anthropometry in soccer using a bibliometric analysis. The following databases were consulted: Scopus, Web of Science (WoS), PubMed (Medline), SportDiscus, and the ScienceDirect publishing platform. The study included documents published between 1990 and 2025. Data was selected following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines statement flowchart and subsequently analyzed using Bibliometrix and R software to identify keywords, frequency of occurrence, journal analysis, countries, and other bibliometric indicators. A total of 384 documents met the inclusion criteria. Spain, Italy, Brazil and Portugal stand out as the countries with the highest output. These countries are associated with the most representative authors, led by Suarez-Arrones, L; Nikolaidis, PT; and Campa, F., who are in turn associated with the most representative concepts: „Male“, „Adolescent“ and „Athletic performance“. The most prevalent concepts are population-based: „Adolescent“ and „Young adult“. The top three organizations in terms of contributing to the scientific study of body composition and anthropometry were the University of the Basque Country, Pablo de Olavide University, and the University of Coimbra. It can be observed that most of the literature has focused on youth (29.16% of the total documents), followed by elite players (22.91%) and professionals (14.84%), where the focus is on those aged 14 to 19 years and playing at highly competitive levels, seeking peak performance. Methodological heterogeneity in evaluation protocols constitutes the main structural shortcoming in this field: 32.29% of studies do not specify their protocols, which compromises the comparability of the results. The widespread adoption of international standards, such as the International Society for the Advancement of Kinanthropometry (ISAK) methodology, along with a requirement to indicate the instrument used and the evaluator’s certification level, is a priority for improving the quality of scientific communication in future research.
#11 Short-Term Changes, Individual Variability, and Associations with Baseline Physical Performance in Young Male Soccer Players During the Pre-Season
Reference: Sports (Basel). 2026 Aug 10;14(8):344. doi: 10.3390/sports14080344.
Authors: Artur Avelino Birk Preissler, Filipe Manuel Clemente, Ana Filipa Silva, Rui Sousa Mendes, Pedro Schons
Download link: https://pmc.ncbi.nlm.nih.gov/articles/PMC13517432/pdf/sports-14-00344.pdf
Summary: Monitoring physical performance during the pre-season may help coaches and practitioners interpret short-term changes in young soccer players, although group-level analyses may mask individual variability. This observational longitudinal study analyzed short-term changes, individual variability, and associations between baseline performance and change magnitude in 50 under-17 male outfield soccer players during a 47-day pre-season. Physical performance was assessed before and after the pre-season using the squat jump (SJ), countermovement jump (CMJ), 20 m linear sprint (Sprint-20m), 20 m change-of-direction test (COD-20m), and Yo-Yo Intermittent Recovery Test Level 1 (Yo-Yo IRL1). Significant improvements were observed in SJ (+1.43 cm, p < 0.001), CMJ (+1.37 cm, p < 0.001), and COD-20m (+0.31 km·h-1, p < 0.001), whereas no statistically significant changes were detected in Sprint-20m (-0.14 km·h-1, p = 0.121) or Yo-Yo IRL1 (-26.20 m, p = 0.721). Individual changes were heterogeneous, with 68.0% improving in SJ and COD-20m, 64.0% in CMJ, 40.0% in Sprint-20m, and 54.0% in Yo-Yo IRL1. Exploratory inverse associations were observed between baseline performance and change scores for SJ (ρ = -0.35, p = 0.014), CMJ (ρ = -0.40, p = 0.004), and COD-20m (ρ = -0.30, p = 0.033), whereas no statistically significant associations were detected for Sprint-20m or Yo-Yo IRL1. These findings support integrating group-level changes, individual variability, and baseline-performance context when interpreting short-term physical performance monitoring in youth soccer.
#12 Do Biological Maturity and Motor Performance Influence Perceived Player Quality? Evidence from U-15 Soccer Players
Reference: Sports (Basel). 2026 Aug 7;14(8):342. doi: 10.3390/sports14080342.
Authors: Jakov Marasović, Ante Rađa, Marko Erceg
Download link: https://pmc.ncbi.nlm.nih.gov/articles/PMC13517613/pdf/sports-14-00342.pdf
Summary: This study had two primary first, to examine the influence of biological maturity status and motor performance indicators on coach-assessed player quality in U-15 soccer players; and second, to explore differences in estimated biological age between players of different quality levels. A secondary objective was to identify differences in morphological characteristics and motor performance between players belonging to different bio-banded maturity groups. A total of 240 U-15 male players (14.12 ± 0.84 years) were assessed for estimated biological age (Mirwald method), motor performance (speed and agility tests with and without ball), and perceived quality (5-point scale). Ordinal regression showed that biological age (OR = 2.47) and slalom performance with and without ball, as well as the 20 m sprint with ball, significantly predicted quality, whereas chronological age had a negative effect (OR = 0.44). Biological age differed significantly across quality groups (F = 3.65, p = 0.007, η2 = 0.06), remaining significant after controlling for chronological age (F = 3.78, p = 0.005). Bio-banded groups differed significantly in morphological characteristics and in 20 m sprint performance with and without ball, but most differences were attenuated after adjusting for chronological age. These findings confirm the role of biological maturity in coaches‘ perception of player quality, with agility tests appearing less maturity-biased than speed tests, while highlighting ball-oriented performance as a potential predictor of playing success.
#13 Acute Effects of Guarana (Paullinia cupana) Supplementation on Cognitive Performance, Technical Skills, and Physiological Responses in Amateur Soccer Players
Reference: Sports (Basel). 2026 Aug 3;14(8):329. doi: 10.3390/sports14080329.
Authors: Safwen Rekik, Mohamed Saifedine Fessi, Sami Hidouri, John Elvis Hagan Jnr, Viorel Petru Ardelean, Vlad Adrian Geantă, Khaled Trabelsi, Wassim Moalla
Download link: https://pmc.ncbi.nlm.nih.gov/articles/PMC13517124/pdf/sports-14-00329.pdf
Summary: This study investigated the acute effects of guarana supplementation on cognitive, technical, physiological, and psychological responses in soccer players prior to, during, and following high-intensity 4 vs. 4 small-sided games (SSGs). Thirty-two male amateur soccer players (20.1 ± 2.9 years) completed a randomized, double-blind, placebo-controlled crossover trial involving guarana (300 mg) and placebo, separated by a 7-day washout. After a 70 min absorption period, participants performed the Trail Making Test (TMT-A/B) and Loughborough Soccer Passing Test (LSPT) before and after a 20 min SSG protocol. Heart rate (HR), HR recovery, perceived physical exertion, perceived mental exertion, mood state, and 24 h wellness were assessed. Guarana significantly improved TMT-A performance compared with placebo (p = 0.005, η2p = 0.05), whereas no significant differences were observed for TMT-B (p = 0.08, η2p = 0.02). A significant Group × Time interaction was found for total LSPT performance time (p = 0.01, η2p = 0.06), driven by a significant technical performance optimization at pre-exercise (p < 0.01) that dissipated post-exercise (p > 0.05). Guarana significantly increased mean exercise HR (p < 0.05) and slowed early recovery kinetics (p < 0.05) without altering perceived physical exertion (p > 0.05). Concurrently, it significantly reduced perceived mental exertion (p < 0.01) and attenuated Total Mood Disturbance (p < 0.001). No significant between condition variations were noted for 24 h wellness indices (p > 0.05). These findings suggest that acute low-dose guarana administration may improve basic attentional readiness and was associated with improved pre-exercise technical performance, although this performance advantage was attenuated following high-intensity physical exertion.
#14 Cold Water Immersion or Foam Rolling? A Randomized Crossover Trial Comparing Recovery Effects on High-Intensity Performance and Markers of Muscle Damage and Inflammation in Soccer Players
Reference: Sports (Basel). 2026 Aug 3;14(8):328. doi: 10.3390/sports14080328.
Authors: Balsam Messai, Slaheddine Delleli, Khaled Trabelsi, Achraf Ammar, Medina Srem Sai, John Elvis Hagan, Vlad Adrian Geantă, Hamdi Chtourou
Download link: https://pmc.ncbi.nlm.nih.gov/articles/PMC13517307/pdf/sports-14-00328.pdf
Summary: Recovery between repeated high-intensity efforts is essential to limit fatigue and performance decline in soccer. This study examined the effects of cold water immersion (CWI), foam rolling (FR), and passive recovery during a 15 min interval between two 5 m shuttle run tests (5mSRTs) on physical performance, perceptual responses, and biochemical markers of muscle damage and inflammation. Fifteen soccer players (age: 22.6 ± 2.03 years) completed passive recovery, FR, and lower-body CWI at 15 °C in a randomized crossover design. Creatine kinase (CK), lactate dehydrogenase (LDH), C-reactive protein (CRP), aspartate transaminase (AST), delayed onset muscle soreness (DOMS), and belief questionnaire scores were assessed before the first 5mSRT and immediately after, and then 24 h, 48 h, and 72 h after the second 5mSRT. Between the first and the second 5mSRT, TD remained unchanged following CWI (p = 0.21), whereas significant decreases were observed following passive recovery (p = 0.025) and FR (p = 0.028). Also, BD decreased after passive recovery (p = 0.03). At 48 h, CWI elicited lower CK (p = 0.01) and LDH (p = 0.003) than passive recovery, whereas FR resulted in lower AST concentrations (p = 0.01). Participants reported higher belief scores following CWI and FR than passive recovery throughout the recovery period (p < 0.05). No between-condition differences were observed for FI, PD, RPE, DOMS, or CRP (all p > 0.05). CWI may help preserve repeated-running performance and attenuate selected markers of muscle damage following repeated high-intensity intermittent exercise in soccer players, whereas FR demonstrated only limited physiological effects.
#15 A matter of time or timing: longitudinal analysis of sensitive periods for linear running speed performance and development in elite youth soccer
Reference: Biol Sport. 2026 Apr 20:43:1341-1351. doi: 10.5114/biolsport.2026.161105. eCollection 2026 Jan.
Authors: Maros Kalata, Jakub Lukavsky, Diogo V Martinho, Craig A Williams, Jan M Konarski, Frantisek Zahalka, Robert M Malina, Tomas Maly
Download link: https://pmc.ncbi.nlm.nih.gov/articles/PMC13504958/pdf/JBS-43-57923.pdf
Summary: The objective of the study was to characterize variability in the development of maximal running speed among elite youth soccer players by evaluating its non-linear trajectory relative to both chronological age and biological maturation, and to determine how these trajectories vary relative to estimated maturity timing. A mixed-longitudinal sample of 117 male youth soccer players (10.7-15.9 years, 461 observations) was considered. Maximal running speed was measured via a 20-meter flying sprint. Biological maturity status was estimated as the percentage of predicted adult height (%PAH), and players were classified as early, average, or late maturing. Non-linear developmental trajectories were analyzed using Generalized Additive Mixed Models. Relative to estimated biological maturity status, a consistent peak rate of speed improvement at ~94.4% PAH was noted and it was preceded by a phase of accelerated improvement between ~87.6-90.7% PAH. However, relative to chronological age, the timing of the accelerated developmental phase was related to estimated maturity timing; early and average maturing players experienced this interval of accelerated gains at a significantly younger age than late-maturing peers, who showed no sustained period of acceleration. Maximal running speed performance in youth soccer players is related to biological maturity status rather than chronological age. The identified phases of accelerated improvement represent developmentally meaningful periods that may help contextualize individual differences in the development of sprinting performance and support maturity-based approaches to long-term athlete development, talent identification, and performance monitoring.
#16 Impact of biological maturation on match workload in Portuguese elite male academy soccer players
Reference: Biol Sport. 2026 Apr 20:43:1329-1340. doi: 10.5114/biolsport.2026.161102. eCollection 2026 Jan.
Authors: Nuno Ribeiro, Oliver Gonzalo-Skok, João Valente-Dos-Santos, Mauro Mandorino, Marco Beato, Jamie Salter, Hadi Nobari, Nuno Loureiro, Ruben Ferreira, João Pedro Araújo, Francisco Tavares
Download link: https://pmc.ncbi.nlm.nih.gov/articles/PMC13504954/pdf/JBS-43-57920.pdf
Summary: Youth soccer academies are essential for identifying and developing talented players, yet substantial inter-individual variability in biological maturation may influence match workload beyond chronological age. This study investigated the independent and interactive effects of biological maturation and age on match workload in elite male youth soccer players (U14-U17). Sixty Portuguese academy players were assessed at six time points across two competitive seasons (2021-22 and 2022-23). Biological maturation was classified using the percentage of predicted adult height, grouping players as pre-/circa-PHV and post-PHV. Mixed-effects models were used to examine the effects of age, maturity status, and their interaction on match workload metrics. Chronological age significantly influenced high-speed running (β = 0.527, p = 0.001) and sprint distance per minute (β = 0.174, p = 0.001). In contrast, total distance per minute and total accelerations and decelerations per minute were shaped by significant age × maturity interactions (p ≤ .001), indicating stronger maturityrelated effects at younger ages that attenuated across adolescence. Chronological age alone does not adequately account for variability in match workload among elite youth soccer players. Biological maturation plays a significant role, in conjunction with age, in determining the demands of total distance and acceleration/deceleration, with more pronounced effects observed at younger ages and a diminishing influence as players reach post-peak height velocity (PHV) stages. Conversely, high-speed running and sprinting distances are primarily influenced by age. These findings underscore the necessity of incorporating biological maturity into the interpretation of match workload, particularly during early to-mid adolescence.
#17 The Effect of a Mindfulness-Based Training on Soccer Skills and Mental Focus in Male Students Aged 10 to 14
Reference: Int J Sch Health. 2026 Jul 1;13(3):248-256. doi: 10.30476/intjsh.2026.107779.1537. eCollection 2026 Jul.
Authors: Mohammad Yousefi, Razieh Khanmohammadi
Download link: https://pmc.ncbi.nlm.nih.gov/articles/PMC13504177/pdf/intjsh-13-3-248.pdf
Summary: Mindfulness-based training (MBT) can improve cognitive function, emotional regulation, and motor performance in sports settings. Given the importance of both technical skills and attentional abilities in soccer performance, this study aimed to investigate the impact of MBT on shooting, passing, and mindfulness in male novice players aged 10-14. This quasi-experimental study employed a pre-test-post-test design with a control group and was conducted from June to August 2024 at the indoor sports complex of Miandoab County, West Azerbaijan Province, Iran. Forty novice male football players aged 10 to 14 years were recruited using a convenience sampling method and randomly allocated to either the intervention or control group through simple randomization using sealed, opaque envelopes. The intervention group received mindfulness-based training (MBT) combined with football skill training, whereas the control group received football skill training alone. The intervention period lasted four weeks, during which both groups trained three times per week. Each session for the intervention group consisted of 20 minutes of football skill practice followed by 20 minutes of MBT exercises, while participants in the control group completed 20 minutes of football skill practice only. Shooting skill, passing skill, and mindfulness, assessed using the Mindfulness Inventory for Sport (MIS), were measured at baseline and after the intervention. Data were analyzed using analysis of covariance (ANCOVA) in SPSS version 26. The intervention group showed significant improvements in mindfulness (Pre: 58.50±15.22, Post: 65.75±12.47, P<0.001), football shooting accuracy (Pre: 47.95±9.10, Post: 58.85±13.51, P=0.012), and passing accuracy (Pre: 7.00±1.55, Post: 9.65±3.01, P=0.028) compared with the control group, which showed no significant changes. Between-group analysis controlling for baseline scores confirmed these differences (mindfulness P=0.001, shooting P=0.001, passing P=0.001) with moderate to large effect sizes (partial η²=0.30-0.87), highlighting the practical significance of mindfulness training on mental and technical performance in novice male players. Mindfulness-based training combined with football skill drills significantly enhances shooting and passing performance, as well as mindfulness levels, in novice male football players aged 10 to 14. Given the critical developmental stage and the school-based context of youth sports, integrating MBT practices into school football training programs can effectively improve both technical skills and mental focus. Coaches and educators are encouraged to implement mindfulness interventions as a practical, accessible approach to support the holistic development of young athletes within school environments.
#18 Impact of Ramadan on Body Composition in Elite Youth Soccer Players: A Case Study
Reference: Int J Sports Physiol Perform. 2026 Aug 25:1-3. doi: 10.1123/ijspp.2026-0034. Online ahead of print.
Authors: Ibrahim Akubat, Capucine Bartrand, Ben Simpson, Juan Jose Morillas Pedreno, Karim Chamari
Summary: This case study examined the impact of Ramadan intermittent fasting on body composition in elite youth soccer players competing in Europe. Ramadan fasting poses unique physiological challenges for athletes, yet research in elite youth populations remains limited. Three male elite youth soccer players (aged 17-18 y) were monitored during Ramadan 2025. Body composition was assessed using dual-energy X-ray absorptiometry at the start and end of Ramadan. Variables included body mass (BM), lean BM, fat mass, fat-free mass, percentage body fat, and bone mineral density. Players maintained their usual training schedule and received tailored nutritional support, including periodized carbohydrate intake (5-10 g·kg BM-1) and protein targets (1.8-2.2 g·kg BM-1). Body composition was largely maintained across the fasting period. Players A and C showed negligible changes. Player B demonstrated a notable reduction in BM (-2.21 kg), primarily due to decreased lean BM (-2.12 kg), despite stable fat mass. Bone mineral density remained unchanged for all players. Informed support strategies can help maintain body composition during Ramadan in elite youth soccer players but players may experience negative consequences and reductions in lean BM, indicating a need for individualized monitoring and intervention. Further research should explore dietary compliance and training load interactions to optimize performance and health during Ramadan intermittent fasting.
#19 Reframing Hamstring Strain Injury Risk in Soccer: A Sprint Mechanism-Oriented ‚Hardware-Software‘ Perspective
Reference: Sports Health. 2026 Sep-Oct;18(5):923-927. doi: 10.1177/19417381261452925. Epub 2026 Aug 24.
Authors: Jurdan Mendiguchia, Gerard Carmona
Download link: https://pmc.ncbi.nlm.nih.gov/articles/PMC13504093/pdf/10.1177_19417381261452925.pdf
#20 Touch Restriction Versus Free-Play Small-Sided Games in Soccer: Acute Effects on Serum BDNF, Executive Function, and Technical Actions
Reference: Eur J Sport Sci. 2026 Sep;26(9):e70242. doi: 10.1002/ejsc.70242.
Authors: Yakup Zühtü Birinci, Serkan Pancar, Yusuf Soylu, Emre Sarandöl, Hasan Şimşek, Şenay Şahin, Michael C Rumpf
Download link: https://pmc.ncbi.nlm.nih.gov/articles/PMC13499902/pdf/EJSC-26-e70242.pdf
Summary: This study aimed to compare the acute effects of two 4v4 small-sided game (SSG) formats, touch-restricted SSG (SSGt) and free-play SSG (SSGf), on serum brain-derived neurotrophic factor (BDNF) levels, cognitive performance, and technical actions in young male soccer players. Thirty-two young male soccer players completed two 4v4 SSG conditions in a randomized crossover SSGt (a maximum of two ball touches per possession) and an SSGf. Serum BDNF was measured before and after each session. Executive function was assessed with the Stroop task, cognitive load was evaluated with the Rating Scale of Mental Effort (RSME), and technical actions were analyzed through match performance metrics. Internal load was monitored using heart rate, rating of perceived exertion, and blood lactate levels. Serum BDNF increased significantly only in the SSGt condition, with higher post-exercise values than in the SSGf condition. Mental effort was also significantly greater in SSGt. Executive function performance improved only in SSGt, as reflected by faster completion time in the incongruent color-word interference condition, whereas errors and corrections did not differ between conditions. Moreover, SSGt showed higher numbers of successful passes and shots, fewer unsuccessful passes, and lost balls, whereas interceptions were higher in SSGf. In conclusion, 4v4 SSG with a touch restriction may be a useful strategy for shaping acute neurotrophic, executive-function, and technical-action responses in soccer players. These findings suggest that touch restrictions may help coaches broaden the training stimulus of SSG by increasing cognitive demands without reducing technical effectiveness.
#21 Lower limb muscle strength, inter-limb asymmetry, and vertical jump performance in elite female football players: A cross-sectional study
Reference: PLoS One. 2026 Aug 28;21(8):e0350952. doi: 10.1371/journal.pone.0350952. eCollection 2026.
Authors: Danail Georgiev Ivanov, Petar Peev
Download link: https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0350952
Summary: Lower limb strength imbalance and inter-limb asymmetry are relevant neuromuscular screening markers in women’s football, yet data from national-champion squads in Eastern Europe remain limited. The aim of this study was to characterise lower limb isometric knee strength, hamstring-to-quadriceps (H:Q) ratios, and bilateral and unilateral squat jump (SJ) and countermovement jump (CMJ) performance, and to describe their distribution by playing position, in elite Bulgarian female football players. Nineteen players from FC NSA Sofia Women (Bulgarian Women’s Football Champions, 2024/25; age 20.9 ± 4.3 years; height 168.4 ± 4.7 cm; body mass 60.5 ± 8.0 kg; body mass index 21.3 ± 2.7 kg·m-2) were assessed on a single testing day using a handheld dynamometer (Kineo Intelligent Load) and an optical jump system (Optojump Next). Mean H:Q ratios were 0.58 ± 0.10 (left, 95% CI [0.52, 0.64]) and 0.55 ± 0.07 (right, 95% CI [0.51, 0.60]); the right-limb mean was statistically below the 0.60 reference threshold (t(13) = -2.40, p = 0.032, d = -0.64). Thirteen of fourteen assessed players (92.9%, 95% CI [68.5-98.7%]) presented at least one limb with an H:Q ratio below 0.60. Mean bilateral SJ and CMJ were both 29.2 cm, producing a near-zero elasticity index (0.99 ± 10.6%). Unilateral asymmetry exceeding 10% was observed in 52.9% of players for SJ (95% CI [31.0-73.8%]) and 35.3% for CMJ (95% CI [17.3-58.7%]). Positional profiles are reported descriptively only, given the small subgroup sizes. The findings support routine neuromuscular screening of lower limb strength balance and unilateral jump performance in elite women’s football, and indicate that conditioning programmes should address both hamstring and quadriceps capacity rather than hamstring strength in isolation.
#22 The Effect of Stud Flexibility on Lower Limb Biomechanical Demands in Football-Specific Movements
Reference: Sports Health. 2026 Aug 27:19417381261471422. doi: 10.1177/19417381261471422. Online ahead of print.
Authors: Gabriele Azzolini, Silvia Fantozzi, Andrea Ferretti, Ezio Preatoni
Summary: Stud design is critical in modulating impact forces between football boot and turf, yet most systems prioritize traction using rigid materials, largely neglecting the role of material flexibility in load attenuation. This study assessed the biomechanical effects of 2 novel flexible stud designs compared with a traditional rigid stud during football-specific cutting and landing tasks. Replacing traditional rigid studs with more flexible alternatives would reduce the magnitude and increase the time-to-peak of key lower limb loading variables. Crossover study design. Level 3. Fourteen recreational male players performed a planned 90° cut, a 180° cut, and a single-leg drop-land-and-cut on dry 3G turf wearing the same boot with 3 different stud sets: rigid (STD), flexible (OPT), and more flexible (FLX). Data analysis included scalar comparisons (approach speed, stance time, loading rates) and full-waveform analysis: amplitude-phase registration on ground reaction forces (GRFs) only, along with statistical parametric mapping of GRFs, knee kinematics, and moments. Subjective perception was assessed using a visual analog scale. Participants rated flexible studs higher for stability, comfort, and overall appreciation. Approach speed and stance time were invariant across conditions. In 180° cuts, loading rates were higher with STD than FLX in both vertical (+33.42%) and mediolateral directions (+36.91%). Amplitude-phase analysis showed significant temporal shift during early stance, with STD exhibiting a phase lead compared with FLX. In 90° cuts, the pattern was similar: higher mediolateral loading rate with STD versus FLX (+25.06%) and STD inducing earlier GRF onsets. Knee dynamics did not show evidence of change. Increasing stud flexibility affected the timing of early load uptake – delaying and flattening the initial GRF rise – while improving perceived stability/comfort and preserving perceived grip. This exploratory study identifies stud flexibility as an actionable design lever to mitigate highly impulsive loading, providing a mechanism for attenuating lower-limb load exposures in early stance – a period highly relevant to noncontact anterior cruciate ligament injury risk, showing better subjective perception of comfort and stability and without degrading overall player performance.
#23 Academy prospect to first team regular: Elite head coach and player experiences of youth to first team transition in football
Reference: J Sports Sci. 2026 Aug 27:1-16. doi: 10.1080/02640414.2026.2722784. Online ahead of print.
Authors: Mark McGuigan, Antonio Dello Iacono, Allistair McRobert, Daryl Cowan, Viswanath B Unnithan
Summary: Current literature has shown that transition from academy to first team in elite football is highly challenging and often turbulent. One perspective yet to be explored is that of elite level players who have experienced the entire transition process from academy football to the first team. In addition, an examination of the perceptions of an elite first team head coach would provide a complementary perspective to these insights. Accordingly, this study aimed to generate novel findings by examining the transition experiences and perceptions of a first team head coach (n = 1) and first team players (n = 4) at an elite club. Participants were purposefully sampled and interviewed to extract rich data sets. Thematic analysis of interview data generated 3 themes: (1) mentality over talent, (2) adaptation to first team, and (3) bridging the gap. The findings support mental strength, and in particular, resilience, as being critical aspects of successful first team transition at the elite level and highlight the nature of the hyper-demanding environment players are required to integrate into. The findings provide novel insights to first team transition from the perspective of first team players and the head coach at an elite club.
#24 Football-Specific Performance and Cognitive Fatigue Resistance Following Supplementation with Two Phosphatidylserine Doses Combined with Taurine and Caffeine in Professional Male Football Players: A Randomized, Triple-Masked, Placebo-Controlled Trial
Reference: Nutrients. 2026 Aug 7;18(16):2588. doi: 10.3390/nu18162588.
Authors: Krzysztof Mizera, Dominik Mazurek, Alejandro Martínez-Rodríguez, Anna Kęska
Download link: https://www.mdpi.com/2072-6643/18/16/2588
Summary: Cognitive fatigue and impaired psychomotor function may contribute to reductions in football-specific performance during prolonged match-like activity. This study evaluated cognitive, psychomotor, sprint, and football-specific locomotor responses to multi-ingredient protocols containing taurine, caffeine, and either 300 or 600 mg·day-1 of phosphatidylserine in professional male football players. In this randomized, triple-masked, placebo-controlled, parallel-group trial, 97 professional male football players were allocated to placebo (PLA, n = 24), taurine plus caffeine (TC, n = 24), taurine plus caffeine plus phosphatidylserine 300 mg·day-1 (TCP-300, n = 24), or taurine plus caffeine plus phosphatidylserine 600 mg·day-1 (TCP-600, n = 25) for 14 days. Taurine and caffeine doses were 1500 mg·day-1 and 200 mg·day-1, respectively. Outcomes included 30 m sprint performance, visual and auditory reaction time, Stroop-task performance, perceived mental fatigue, GPS-derived locomotor variables, and post-intervention first-to-second-half performance-loss indices during a standardized football-specific exercise protocol. The baseline-adjusted ANCOVA demonstrated a significant treatment-group effect on post-intervention 30 m sprint time. After Holm-Bonferroni correction, significant treatment-related effects remained for Stroop reaction time, visual reaction time, and perceived mental fatigue. No statistically significant treatment-related effect was observed for auditory reaction time (unadjusted p = 0.074; Holm-adjusted p = 0.096). During the post-intervention standardized football-specific protocol, baseline-adjusted GPS-derived locomotor outcomes differed significantly between groups. First-to-second-half performance-loss indices also differed between groups, with the smallest post-intervention losses generally observed in TCP-600. Because comparable decline indices were unavailable at baseline, these findings do not represent intervention-related changes in fatigue resistance. Under the present 14-day experimental conditions, the multi-ingredient protocols containing taurine, caffeine, and phosphatidylserine were associated with more favorable selected cognitive and psychomotor outcomes, 30 m sprint performance, and baseline-adjusted GPS-derived locomotor outcomes than placebo. The groups also differed in post-intervention first-to-second-half performance loss during the standardized football-specific protocol. Because corresponding decline indices were not assessed at baseline, these findings do not demonstrate an intervention-related improvement in fatigue resistance. Numerically more favorable values were observed for several outcomes in TCP-600; however, differences between TCP-300 and TCP-600 were modest and not consistently statistically significant, and the study was not specifically powered to establish a dose-response relationship. Because phosphatidylserine was not tested independently, these findings should be interpreted as responses to the combined multi-ingredient supplementation protocols rather than as effects of phosphatidylserine alone.
#25 Effects of Halotherapy as an Adjunct to Preseason Training on Respiratory and Aerobic Outcomes in Elite Female Football Players: A Randomized Controlled Trial
Reference: Life (Basel). 2026 Jul 25;16(8):1233. doi: 10.3390/life16081233.
Authors: Derya Çetin Sarışık, Ahmet Serhat Aydın, Mehmet Söyler, Raif Zileli, Ali Özkurt, Coskun Yılmaz, Hamza Küçük, Mevlüt Karataş
Download link: https://www.mdpi.com/2075-1729/16/8/1233
Summary: Aerobic capacity and respiratory efficiency are critical determinants of performance in elite female football, characterized by repeated high-intensity efforts and rapid recovery demands. Halotherapy, involving the inhalation of dry salt aerosol, has been shown to improve pulmonary health; however, its effects on exercise-related outcomes in athletic populations remain insufficiently investigated. This study aimed to examine the effects of a 12-week post-training halotherapy intervention on respiratory muscle strength, pulmonary function, and aerobic performance in elite female football players. Twenty-eight elite female football players competing in the Turkish Women’s First League were randomly assigned to a halotherapy group (HG, n = 14) or a control group (CG, n = 14). Both groups completed an identical preseason training program, while the HG additionally performed 45 min halotherapy sessions three times per week in a controlled halochamber. Pre- and post-intervention assessments included maximal inspiratory and expiratory pressures (MIP, MEP), spirometric parameters (FVC, FEV1, PEF, MVV), and maximal oxygen uptake (VO2max) estimated using the Yo-Yo Intermittent Recovery Test Level 1 (Yo-Yo IRT1), along with total distance covered. A 2 × 2 mixed-model ANOVA was used to assess time and group × time interaction effects. Significant group × time interactions were observed for MIP, MEP, VO2max, FEV1, PEF, MVV, and Yo-Yo IRT1 performance (p < 0.05), with large effect sizes (ηp2 = 0.269-0.924), favoring the halotherapy group. Forced vital capacity (FVC) increased over time in both groups (p = 0.141), with no significant interaction effect. Changes in the control group were comparatively smaller across most outcomes. Post-training halotherapy was associated with improvements in respiratory muscle strength, ventilatory function, aerobic capacity, and intermittent running performance in elite female football players. These findings suggest that halotherapy may be considered as a complementary, non-invasive strategy to support respiratory and aerobic adaptations. Further research is required to confirm these findings and to clarify the underlying physiological mechanisms.
#26 Polygenic Profiles Are Associated with Multidomain Biochemical Adaptations Across a Competitive Season in Professional Football Players: A Longitudinal Observational Study
Reference: Genes (Basel). 2026 Aug 7;17(8):927. doi: 10.3390/genes17080927.
Authors: Jorge Carretero-García, David Varillas-Delgado
Download link: https://www.mdpi.com/2073-4425/17/8/927
Summary: The physiological adaptations required to sustain elite football performance are influenced by both genetic background and dynamic biochemical responses, although their interaction across a full competitive season remains insufficiently characterized. This study aimed to examine the association between polygenic profiles and longitudinal biochemical adaptations in professional football players. Forty male professional football players competing in the Spanish league were monitored across two consecutive seasons. Blood samples were collected at six time points representing different phases of the competitive cycle. Biomarkers related to muscle metabolism, iron status, and hepatic function were analyzed. Polygenic profiles were calculated using Total Genotype Scores (TGS) for muscle performance, hepatic resilience, and metabolic efficiency. Associations were initially explored using Pearson correlations and subsequently evaluated using linear mixed-effects models accounting for repeated measurements within subjects. Exploratory correlation analyses identified several associations between polygenic profiles and biochemical markers. Muscle performance TGS was inversely associated with serum iron (r = -0.36, p = 0.017) and positively associated with CK (r = 0.32, p = 0.041), Hb (r = 0.29, p = 0.046), and Hct (r = 0.33, p = 0.024). Hepatic resilience TGS showed inverse associations with ALT (r = -0.39, p = 0.012), urea (r = -0.51, p = 0.011), and BUN (r = -0.51, p = 0.011). Metabolic efficiency TGS was negatively associated with AST (r = -0.43, p = 0.044), ALT (r = -0.33, p = 0.025), and GGT across multiple time points (p = 0.001-0.013). However, although several nominal associations emerged in linear mixed-effects models accounting for repeated measurements, none remained statistically significant after false discovery rate correction. These findings should therefore be interpreted as exploratory and hypothesis-generating. Polygenic profiles may be associated with inter-individual variability in biochemical adaptations throughout a competitive season. These findings suggest the integration of genomic and biochemical data in precision athlete monitoring, while highlighting causal relationships and predictive applications require further investigation.
#27 The Relationship Between Upper Extremity Performance, Core Endurance, and Balance in Adolescent Football Players
Reference: Sportverletz Sportschaden. 2026 Aug 26. doi: 10.1055/a-2912-1378. Online ahead of print.
Authors: Aslıhan Parlak, Zeynep Hoşbay, Berivan Beril Kılıç, Hüseyin Kavak
Summary: in English, German Upper extremity performance is a key component of the kinetic chain, facilitating force transfer and postural control during football-specific tasks. This study aimed to investigate the relationship between upper extremity stability, core muscle endurance, and dynamic balance in adolescent football players to clarify how upper body performance relates to overall athletic capacity. It was hypothesized that upper extremity performance, core muscle endurance, and dynamic balance would be positively associated. This observational study evaluated 52 male adolescent football players (13.25±1.08 years) who regularly trained for at least 60 minutes on two or more days per week and had participated in organized team football for at least one year. Assessments included the Closed Kinetic Chain Upper Extremity Stability Test (CKCUEST), Upper Quarter Y-Balance Test (UQYBT), core muscle endurance tests, and Lower Quarter Y-Balance Test (LQYBT), and the relationships among these measures were analyzed. No significant differences were observed between dominant and non-dominant sides in LQYBT and most UQYBT directions (p>0.05), except for lower superolateral reach on the dominant side (p=0.036). CKCUEST performance was positively correlated with UQYBT (r=0.371-0.433, p<0.05) and core muscle endurance (r=0.580-0.695, p<0.001). UQYBT performance was also associated with the LQYBT composite scores (r=0.506-0.529, p<0.001) and core muscle endurance (r=0.285-0.569, p<0.05), while LQYBT performance correlated with core flexion and extension endurance (r=0.280-0.576, p<0.05). Upper extremity performance plays an important role in the athletic performance of adolescent football players and is associated with core muscle endurance and lower extremity dynamic balance, supporting the concept of balance as an integrated bodily function. The findings suggest that integrated stability and balance training may enhance athletic performance and support injury prevention.
#28 Intra- and Inter-Rater Reliability of Primitive Reflex Assessments in Youth Football Athletes
Reference: J Funct Morphol Kinesiol. 2026 Aug 21;11(3):324. doi: 10.3390/jfmk11030324.
Authors: Julie Bastiere, Aurélien Patoz, Thibault Lussiana, Marvin Subryan, Cyrille Gindre, Laurent Mourot
Download link: https://www.mdpi.com/2411-5142/11/3/324
Summary: Primitive reflex (PR) assessments based on the Institute for Neuro-Physiological Psychology (INPP) framework are increasingly used in developmental and athletic populations. However, the reproducibility of these observer-based assessments remains insufficiently documented. This study investigated the intra- and inter-rater reliability of subjective PR assessments and examined the potential influence of evaluator expertise in elite youth football athletes. Sixty-nine male youth football players from an elite academy (age: 18 ± 2 years) participated in this study. PR assessments included the Moro reflex, asymmetrical tonic neck reflex, symmetrical tonic neck reflex, and tonic labyrinthine reflex, evaluated using standardized INPP procedures (0-4 ordinal scoring scale). Intra-rater reliability was assessed by an experienced examiner across three testing sessions performed over six months. Inter-rater reliability was evaluated using standardized video recordings independently scored by two novice raters. Relative reliability was assessed using intraclass correlation coefficients (ICCs) with corresponding 95% confidence intervals (95% CIs), while absolute reliability was quantified using the standard error of measurement (SEM) and the minimal detectable change at the 95% confidence level (MDC95). Good to excellent intra-rater relative reliability (ICC = 0.86-0.98; 95% CI = [0.81-0.99]) was observed, with SEM values of 0.1-0.6 and MDC95 values of 0.3-1.7 points. Moderate to excellent video-based inter-rater reliability was found (ICC = 0.69-0.99; 95% CI [0.56-0.99]), with SEM values of 0.1-0.7 and MDC95 values of 0.3-2.0 points. Pairwise comparisons among raters showed moderate to excellent relative reliability (ICC = 0.57-0.99; 95% CI [0.35-0.99]), with SEM values of 0.1-0.5 and MDC95 values of 0.2-1.3 points. Subjective PR assessments performed using the INPP framework demonstrated good to excellent intra-rater relative reliability and moderate to excellent video-based inter-rater relative reliability, together with generally low absolute measurement error in elite youth football athletes. These findings provide preliminary psychometric support for the use of standardized PR assessments in research and applied sport settings.
#29 Position-Specific External Load Between Official Matches and Small-, Medium- and Large-Sided Games in Professional Football
Reference: J Funct Morphol Kinesiol. 2026 Aug 3;11(3):306. doi: 10.3390/jfmk11030306.
Authors: Lukas Herzig, Jörg Stöckert, Matthias Lochmann, Michael C Rumpf
Download link: https://www.mdpi.com/2411-5142/11/3/306
Summary: Sided games are commonly used to condition players for the demands of official games (OGs). Therefore, this study aimed to evaluate if different sided games match position-specific locomotor and mechanical OG demands of professional football players. Twenty-one male professional football players from a second team of a professional football club were monitored during the second half of the 2024/25 season. External load was assessed during OGs and sided games. The latter were categorized by area per player (ApP) as small- (SSG, ApP < 100 m2), medium- (MSG, ApP 100-200 m2) and large-sided games (LSG, ApP > 200 m2). External load was analyzed for total distance (TD), high-speed running (HSR), sprint distance (SPD), and the number of accelerations (ACC) and decelerations (DEC). Players were grouped by position: center backs (CBs), full backs (FBs), central midfielders (CMs), wide midfielders (WMs), and strikers (STs). Across all playing positions (CB, FB, CM, WM, ST), SSGs, MSGs and LSGs elicited significantly higher TD than the OG, except for CM, where no significant differences were observed during SSGs and LSGs. All positions displayed similar HSR during LSGs than OG demands, and some positions also during MSGs (CB, CM, FB) and SSGs (CB). SPD was similar across all positions only during LSGs. ACC and DEC were significantly higher for all positions in SSGs and MSGs than OGs and similar in LSGs. Position-specific OG demands were not statistically from different sided-game formats. ACC, DEC and TD in LSGs met OG demands; however, smaller formats (SSGs, MSGs) overload those variables. In contrast, HSR and SPR load in SSGs and MSGs did not meet OG demands for most positions. For that, coaches should use LSGs, knowing that TD may be overloaded, or supplement SSGs/MSGs with running-based drills for more accurate programming.
#30 A Position-Specific, Time-Efficient Warm-Up Injury Prevention Program in Male Football Players: A Season-Long Intervention Study
Reference: Sports (Basel). 2026 Aug 7;14(8):340. doi: 10.3390/sports14080340.
Authors: Dimitrios Vlachodimos, Athanasios A Dalamitros, Vasiliki Manou, Thomas Metaxas, Nikolaos Stavropoulos, Ioannis Terzidis
Download link: https://pmc.ncbi.nlm.nih.gov/articles/PMC13517201/pdf/sports-14-00340.pdf
Summary: This study assessed the effectiveness of a position-specific and time-efficient warm-up injury prevention program for male football players. This season-long quasi-experimental study included 129 male amateur football players. A structured injury prevention program was incorporated into the warm-up routine during the preseason and competitive season. Prospectively collected injury data from the intervention season were compared with retrospectively collected injury data from the previous season and included injury incidence, the number of injured players, injury severity, and injury burden. The program included general exercises and position-specific modifications for defenders, midfielders, and attackers. Implementation of the program was associated with a 60% reduction in total injuries (p < 0.05) and a 60.3% reduction in total injured players The injury burden was significantly reduced (p < 0.05), as indicated by a reduced mean day lost per injury from 33.24 to 19.56 days. Although injury reductions were observed across all playing positions, between-position differences were not statistically significant. The type of injuries and their mechanisms were not significantly affected. These preliminary, associative findings suggest that a time-efficient, position-specific warm-up program may contribute to reduced injury occurrence in amateur football; however, given the quasi-experimental design, confirmation through randomized controlled trials is required.
#31 Adaptive Athlete Management in Youth Football: A Developmentally Informed Framework for Applied Practice
Reference: Sports (Basel). 2026 Aug 1;14(8):324. doi: 10.3390/sports14080324.
Authors: Nikolaos Androulakis, Nikolaos Koundourakis
Download link: https://pmc.ncbi.nlm.nih.gov/articles/PMC13517846/pdf/sports-14-00324.pdf
Summary: Youth football academies increasingly utilize physical testing, athlete monitoring, anthropometric profiling, and performance analysis to support athlete development and training management. During adolescence, rapid biological maturation, fluctuating neuromuscular coordination, variable recovery capacity, and ongoing psychological development may substantially influence physical and football-specific performance over time. Consequently, athlete-management decisions based exclusively on isolated testing outcomes may inadequately reflect the developmental needs of young players. This narrative review presents a developmentally informed framework for applied athlete management in youth football academies. The review discusses the interaction between football-specific technical and tactical qualities, physical performance characteristics, biological maturation, somatometric profile, psychological and perceptual-cognitive factors, recovery management, and monitoring strategies during adolescent development. Particular emphasis is placed on practical implementation within real-world academy environments, including low-cost monitoring approaches, intra-club bio-banding, multidisciplinary communication, and athlete-specific intervention planning. Overall, the proposed framework positions athlete monitoring as a continuous support process designed to guide training adjustment, recovery management, and sustainable football progression within youth football development pathways.
#32 Conservative management of an isolated near-complete distal biceps femoris tendon rupture in an elite football player
Reference: BMJ Case Rep. 2026 Aug 25;19(8):e273376. doi: 10.1136/bcr-2026-273376.
Authors: Silke Bijnens, Peter Wildiers, Kristin Suetens, Brahim Hacene
Summary: This case report presents an adolescent elite football player who sustained an isolated, near-complete rupture of both the long and short heads of the distal biceps femoris tendon, with approximately 20 mm tendon retraction and no associated bony avulsion or posterolateral knee injury. The injury occurred during a forceful cross-kick and was initially challenging to characterise because of conflicting ultrasound and MRI findings. Given the preserved clinical function, limited retraction and evidence of residual tendon continuity, the medical team opted for conservative management, without bracing or surgery. The athlete completed a structured criterion-based rehabilitation programme with close clinical, imaging and load monitoring. Progressive tendon healing was demonstrated on serial MRI, and the player achieved full return to play within 22 weeks. This case highlights that non-operative management of high-grade distal biceps femoris tendon ruptures may represent a feasible alternative to surgery in carefully selected athletes.
#33 No differences between cold and hot water immersion for neuromuscular recovery, sprint mechanics and delayed onset muscle soreness after a simulated football game
Reference: J Sports Sci. 2026 Aug 23:1-11. doi: 10.1080/02640414.2026.2713869. Online ahead of print.
Authors: David Bandiera, Hervé Di Domenico, Pierre Samozino, Sébastien Racinais, Thomas Rupp
Summary: This study aimed to compare the effects of cold (CWI) versus hot (HWI) water immersion on neuromuscular function, sprinting force production, and perceptual responses during a 72-h recovery period following a simulated football match. Twenty-two active males completed a simulated football game and underwent either CWI or HWI immediately post-exercise, and again at 24 h and 48 h. Isometric maximal voluntary contraction (IMVC) of the quadriceps, as well as central and peripheral components of neuromuscular fatigue (via femoral nerve electrical stimulation), were assessed before the simulated match and at 24 h, 48 h, and 72 h post-exercise, as well as maximal power output and its force/velocity components during repeated sprints and a questionaire on perceptual responses. On average, peripheral fatigue was observed with a 7.0% decrease in maximal voluntary contraction (P<0.01), with no central fatigue (P=0.88). A loss of sprinting power output of 8.9% at 24h (P<0.001) was measured, and delayed onset muscle soreness increased at 24h and 48h (P<0.001). No significant differences were found between CWI and HWI for any of these variables during recovery. These findings suggest that HWI may represent a practical and effective alternative to CWI to restore neuromuscular function, sprint mechanics and perceptual responses.
#34 Limited positional differences in lower-limb muscle contractile properties among female football players
Reference: Front Sports Act Living. 2026 Aug 7:8:1915995. doi: 10.3389/fspor.2026.1915995. eCollection 2026.
Authors: Jaroslav Sučka, Frederika Pajonková, Pavol Čech, Rút Lenková
Download link: https://pmc.ncbi.nlm.nih.gov/articles/PMC13493519/pdf/fspor-08-1915995.pdf
Summary: Contractile properties of the lower-limb muscles are closely associated with high-intensity activities performed during a football match. Several studies have indicated that playing position significantly influences players‘ physical and performance demands, as well as the intensity of high-speed locomotor activities during match play. Nevertheless, it remains unclear to what extent muscle contractile properties differ according to specific playing positions in women’s football. Therefore, the aim of this study was to describe the contractile properties of female football players according to playing position. Female football players (n = 52) competing in the highest national league were divided into six groups according to playing position: GK-goalkeepers (n = 4), FB-fullbacks (n = 9), CB-centre-backs (n = 8), W-wingers (n = 10), M-midfielders (n = 13), and F-forwards (n = 8). Muscle contractile properties of the m. biceps femoris, m. gastrocnemius medialis, m. gluteus maximus, m. vastus lateralis, and m. vastus medialis on both the dominant and non-dominant lower limbs were assessed using the parameters contraction time (Tc), maximal radial displacement (Dm), and contraction velocity (Vc), obtained by the non-invasive method of tensiomyography using the TMG S2 system (TMG-BMC Ltd., Slovenia). The Shapiro-Wilk test indicated that the data were not normally distributed. Differences in contractile properties according to playing position were evaluated using the Kruskal-Wallis analysis of variance (K-W ANOVA), followed by Dunn’s post hoc test with Bonferroni correction. Holm-Bonferroni correction was subsequently applied to account for multiple comparisons across all analyzed outcomes. Before adjustment for multiple comparisons, the lowest unadjusted p-value was observed for contraction velocity of the dominant vastus lateralis muscle (H = 12.219, p = 0.032). However, this finding did not remain statistically significant after Holm-Bonferroni correction. No statistically significant positional differences were observed for the remaining muscles or TMG-derived parameters. The findings indicate only limited positional differences in lower-limb muscle contractile properties among elite female football players. However, these findings should be interpreted with caution given the relatively small sample size, particularly the goalkeeper subgroup, and the absence of statistically significant differences after adjustment for multiple comparisons. Nevertheless, tensiomyography appears to be a promising non-invasive tool for individualized neuromuscular monitoring when interpreted alongside other performance and clinical assessments.