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 Health-related effects of walking football in older adults: A real-world longitudinal study across a season comparing two age groups

Reference: PLoS One. 2026 Feb 13;21(2):e0341913. doi: 10.1371/journal.pone.0341913. eCollection 2026.
Authors: Iraia Bidaurrazaga-Letona, Maite Lejonagoitia-Garmendia, Izaro Esain, Iratxe Duñabeitia, Begoña Sanz, Xabier Monasterio, Jone Torre-Sainz, Susana M Gil
Download link: https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0341913
Summary: The aim of the study was to evaluate the health-related effects of a 9-month walking-football (WF) season in already active older adults, comparing participants aged 50-59 and ≥60. The study employed a longitudinal pre-post design conducted in a real-world community setting. The participants were 32 adults aged over 50 (including 2 women) who completed a 9-month, twice-weekly outdoor WF program. Baseline and post-season assessments included body measurements, blood biomarkers, cardiovascular fitness (Bruce protocol), muscle strength (countermovement jump, handgrip strength, and isokinetic measurements), physical activity, and health-related quality of life. Training load was monitored via heart rate and session rating of perceived exertion. Statistical analyses compared pre- and post-season outcomes, as well as differences between age groups (50-59 vs. ≥ 60 years). Anthropometric parameters remained stable over the season, with participants aged 50-59 showing higher weight, BMI, and muscle mass than those aged ≥60 (p < 0.05). Reductions occurred in blood glucose, along with favorable changes in lipid profiles in older participants (p < 0.05), and increased vitamin D (p < 0.05). Creatine kinase (CK), lactate dehydrogenase (LDH), and adiponectin decreased over the season (p < 0.05). Although the differences were not statistically significant, older adults maintained peak VO₂, whereas younger participants exhibited a small decline. Muscle strength decreased across both age groups, specifically handgrip strength and knee extension (p < 0.001-0.05). Physical activity levels showed a non-significant increase in total and high-intensity METs, especially among younger participants. In conclusion, walking football may help preserve cardiometabolic health, functional capacity, and quality of life in physically active older adults throughout a competitive season. Nevertheless, specific program adjustments-such as higher training loads, the inclusion of strength or resistance components, and age-tailored modifications-could be required to maximize outcomes, particularly among younger participants.

2 The moderating role of attachment styles in the relationship between psychological commitment and aggression among football fans

Reference: Front Psychol. 2026 Jan 28:17:1632498. doi: 10.3389/fpsyg.2026.1632498. eCollection 2026.
Authors: Serkan Volkan Sarı, Seher Pamaç, Sabır Sultanoğlu, Onur Göz
Download link: https://pmc.ncbi.nlm.nih.gov/articles/PMC12892969/pdf/fpsyg-17-1632498.pdf
Summary: This study examined how attachment styles condition the relationship between football fans‘ psychological commitment and aggressive tendencies. The sample consisted of 561 adult football supporters who identified themselves as long-term and highly committed fans. A moderation framework was employed to test whether attachment orientations shape the strength and expression of the association between psychological commitment and aggression. Moderation analyses revealed that higher psychological commitment was generally associated with increased aggression; however, this relationship varied significantly as a function of attachment style. Secure attachment attenuated the positive association between commitment and aggression, whereas anxious ambivalent and avoidant attachment styles were associated with higher baseline levels of aggression. Attachment styles function as regulatory lenses through which strong emotional investment in a team translates into either controlled or aggressive responses, offering important implications for prevention and intervention strategies in football environments.

3 The impact of caffeine-mediated gut microbiota regulation on the athletic performance of football players

Reference: Biol Sport. 2025 Aug 6:43:115-125. doi: 10.5114/biolsport.2026.153312. eCollection 2026 Jan.
Authors: Jianlou Yang, Hongda Zhu, Bo Yao, Wei Zhang, Xiaodong Xing, Weibo Cheng, Chen Dong
Download link: https://pmc.ncbi.nlm.nih.gov/articles/PMC12884884/pdf/JBS-43-56517.pdf
Summary: Caffeine is widely utilized as an ergogenic aid in sports, yet its interaction with gut microbiota – a key modulator of metabolic and physiological processes – remains underexplored in athletic populations. This study aimed to investigate whether caffeine supplementation enhances the athletic performance of football players through gut microbiota regulation, thereby bridging the gap between caffeine’s ergogenic effects and microbial mediation mechanisms. A 7-day randomized, double-blind, placebo-controlled trial was conducted with 32 male national-level football players. Participants were allocated to either a caffeine group (3 mg/kg body mass) or a placebo group. Performance assessments included agility tests, 30-m repeated sprints, technical dribbling tasks, and aerobic endurance evaluations. Fecal samples were analyzed via 16S rRNA sequencing to assess microbial diversity and composition. Structural equation modeling (SEM) was employed to evaluate the mediating role of gut microbiota. Caffeine supplementation significantly improved agility (p < 0.001, Cohen’s d = 1.1), sprint performance (p = 0.007, d = 0.7), and technical execution (p = 0.003, d = 0.7) compared to placebo. Gut microbiota alpha diversity (Chao1, Shannon) increased in the caffeine group (p < 0.05), with enrichment of Prevotella, Bacteroides, and Veillonella. SEM revealed that 33.3% of caffeine’s performance-enhancing effect was mediated by microbial diversity (β = 0.2, p = 0.01), while no direct caffeine-performance pathway was observed (p = 0.2). These findings demonstrate that caffeine enhances football-specific performance partially through gut microbiota modulation, emphasizing the microbiome’s role in translating nutritional interventions into athletic gains. Future research should explore long-term microbial adaptations and personalized strategies combining caffeine with microbiome-targeted therapies.

4 How do muscle injuries relate to return-to-performance metrics in male elite football players?

Reference: Biol Sport. 2025 Aug 13:43:165-175. doi: 10.5114/biolsport.2026.153532. eCollection 2026 Jan.
Authors: Marc Guitart, Antonio Alonso-Callejo, Gil Rodas, Francesc Cos, Andres Martin-Garcia, Xavi Franquesa, Berta Carles, Xavier Valle, Xavier Yangüas, Jose Luis Felipe
Download link: https://pmc.ncbi.nlm.nih.gov/articles/PMC12884885/pdf/JBS-43-56543.pdf
Summary: The aim of this study was to analyze how the type, location, and severity of injury are associated with the time elapsed since the return to training and matches of male football players to reach fitness values comparable to pre-injury levels. A longitudinal analysis was conducted on 333 male football players from an elite Spanish football club over five seasons (2017/18 to 2021/22). A total of 234 injuries (including medical attention) were included in the analysis. The study focused on hamstring and quadriceps injuries, examining high-speed running, sprint distance, and maximum velocity before and after injury. Results indicated that hamstring injuries significantly impact Vmax and HSR, with severe injuries requiring up to five weeks to return to pre-injury levels (Vmax: -1.43 km/h, p = 0.01; HSR: -32.90 m, p = 0.04). Quadriceps injuries revealed less impact on performance metrics than hamstring injuries, with only mild injuries resulting in a significant reduction in Vmax (-1.18 km/h, p = 0.04) and HSR (-52.70 m, p = 0.01) during the first week post-injury. The findings highlight the importance of injury-specific rehabilitation protocols and the need for tailored training loads to minimise the risk of re-injury and optimise return to performance. This research provides valuable insights for medical and performance staff in elite football, emphasizing the critical role of injury management in maintaining player performance and club success.

5 Key performance indicators of offensive transitions in elite women’s football: a machine learning and explainability approach

Reference: Biol Sport. 2025 Aug 5:43:53-64. doi: 10.5114/biolsport.2026.153309. eCollection 2026 Jan.
Authors: Claudio A Casal, José Luis Losada, Ana M de Benito Trigueros, Rubén Maneiro, Iyán Iván-Baragaño
Download link: https://pmc.ncbi.nlm.nih.gov/articles/PMC12884906/pdf/JBS-43-56514.pdf
Summary: Women’s football has experienced significant growth in sporting, economic, and social interest. However, there remains a shortage of studies examining key technical-tactical performance indicators in elite competitions. This research aimed to identify and quantify the influence of technical-tactical indicators on the effectiveness of offensive dynamic transitions in elite women’s football, using a machine learning approach. To this end, 3,610 dynamic offensive transitions recorded across 35 matches from the final stages of the FIFA Women’s World Cup 2023, UEFA Women’s Euro, and UEFA Women’s Champions League 2023/24 were analysed using an observational methodology. An ad hoc observation instrument, Transfootb, was developed to record teams‘ offensive behaviours, opponents‘ defensive responses, and the match context at the time of the offensive dynamic transition. A chi-square test was applied to identify associations between variables, followed by the training of a Random Forest model to predict transition outcomes. Additionally, ShAP values were computed and visualised to interpret the influence of the predictors. The model achieved an area under the curve of 0.78, with a recall of 18% and a specificity of 96%. The results indicate that the execution mode of offensive transitions and the match context significantly influence offensive success. Specifically, penetrating passes (≥ 3), counterattacks, and an opponent’s low defensive positioning were the key predictors of successful offensive transitions. This study provides valuable scientific evidence to optimise strategic decision-making in dynamic offensive transitions in elite women’s football. Furthermore, it highlights the potential of machine learning in analysing and predicting performance in sport-specific actions.

6 Injuries according to sexual maturity status: a three-season observational study with male academy players of a professional Spanish football club

Reference: Biol Sport. 2025 Sep 29:43:393-403. doi: 10.5114/biolsport.2026.154143. eCollection 2026 Jan.
Authors: Mauricio Monaco, Eirik Halvorsen Wik, Abdulaziz Farooq, Gil Rodas
Download link: https://pmc.ncbi.nlm.nih.gov/articles/PMC12884892/pdf/JBS-43-56662.pdf
Summary: The current literature suggests that football (soccer) players‘ age and maturity status affect the likelihood of sustaining certain injuries; however, few studies have used indicators of sexual maturity. By retrospectively analysing prospectively collected data, we therefore aimed to describe injury patterns among young football players in a Spanish academy over three seasons and investigate associations with sexual maturity status. Participants included 354 male youth players aged 7 to 18, categorised into five age groups. Maturity assessments were conducted annually, utilising pubertal stages for genitalia and pubic hair, alongside testicular volume measurements. Time-loss injuries were recorded by medical staff and associations with pubertal stages were examined using Generalized Estimating Equations (GEE). Results indicated an overall incidence of 2.2 injuries per 1000 hours. Higher injury rates were observed for more advanced maturational stages (p < 0.05). Common injury types included muscle injuries (23%), joint sprains (20%), and growth-related injuries (16%), with specific injuries varying by maturity stage. For instance, growth-related injuries peaked during mid-puberty, while muscle and joint injuries were more frequent in advanced maturity stages (p < 0.05). Our findings suggest that sexual maturity status was significantly associated with injury occurrence in youth football. This emphasises the importance of understanding the interplay between biological maturity and injury occurrence. In addition to considering players‘ age or playing level, coaches and clinicians may consider tailoring training and injury prevention strategies according to players‘ maturity levels to better mitigate injury risks.

7 Recreational football training preserves bone health in women over 9 years during the menopause transition

Reference: Biol Sport. 2025 Sep 9:43:281-290.  doi: 10.5114/biolsport.2026.154145. eCollection 2026 Jan.
Authors: Magni Mohr, May-Britt Skoradal, Tórur Sjúrðarson, Niklas R Jørgensen, Jann Mortensen, Peter Krustrup
Download link: https://pmc.ncbi.nlm.nih.gov/articles/PMC12884909/pdf/JBS-43-56664.pdf
Summary: We examined the long-term effects of recreational football training on bone mineralization, osteogenic activity, and physical function in women during the menopause transition. 25 women (45 ± 4 yrs at recruitment) were randomized into an exercise group (EXE; n = 12) completing 1-h football training sessions on average 1.7/wk for a consecutive 9-yr period or an inactive control group (CON; n = 13). Pre and post, we measured bone mineralization and lean body mass, plasma bone turnover markers, and sprint performance. Significant time × group interactions were for leg BMD, leg BMC, femur shaft BMD, CTX-I, PINP, leg lean mass, and sprint performance (all p < 0.01), favoring the exercise group. Leg bone mineral density (BMD) decreased (P = 0.002) by 0.05 g/cm2 [-0.08;-0.02] in CON, but was maintained in EXE, resulting in a higher leg BMD in EXE than CON (P = 0.02). Leg bone mineral content (BMC) increased in EXE (time × group, P = 0.005) resulting in a 56 g [4;108] higher (P = 0.04) total leg BMC in EXE compared to CON. A between-group effect existed in favor of EXE for femur shaft BMD (time × group, P = 0.005). Plasma CTX-I and PINP increased (both P = 0.001) by 95% [43;147] and 64% [29-100] following EXE only (time × group, P = 0.003 and 0.02). Leg lean mass increased (P < 0.001) by 1.5 kg [1.0;2.1] in EXE (time × group, P = 0.006). Finally, sprint performance was maintained in EXE but declined (P < 0.001) by 10% [5;14] in CON (time × group, P = 0.002). Recreational football training (on average 1.7 sessions per week) over 9 years preserves leg bone health, muscle mass and functional capacity in women during the menopause transition.

8 Key Performance Indicators in Elite Female Football: Associations Between Sprints, Duels, and Match Results

Reference: Int J Sports Physiol Perform. 2026 Feb 10:1-8. doi: 10.1123/ijspp.2025-0408. Online ahead of print.
Authors: Rodrigo Villaseca-Vicuña, Joel Barrera-Díaz, Fernando Otero-Saborido, Santiago Zabaloy, Edson Palorames, Hugo Sarmento 
Summary: This study aimed to compare and analyze the physical, technical, and tactical performance of players according to match results and to examine the associations between these indicators and match outcomes in official FIFA competitions. A total of 299 data samples were collected from 27 elite female players (age: 27 [3.4] y) across 34 official matches between 2018 and 2021. Internal load (ie, rate of perceived exertion) and external load metrics were collected via 10-Hz GPS, which included total distance, high-speed running, player load, number of sprints, accelerations, and decelerations. In addition, technical-tactical performance-number of passes, effective passes, duels, successful duels, and goals scored and conceded-was assessed using InStat software. One-way analysis of variance and multinomial logistic regression were applied. Lost matches showed a higher rate of perceived exertion, total distance, player load, and decelerations, whereas won matches presented significantly greater high-speed running, effective passes, and duels (P < .05). Match outcome was significantly associated with high-speed running, duels won, and goals scored/conceded. Losses are associated with greater physical demands but lower technical-tactical efficiency, whereas wins are characterized by more frequent high-intensity actions and greater technical-tactical effectiveness, particularly in passing and duels. These results suggest that, in female football, performance success depends more on the quality of actions than on overall physical exertion.

9 Effects of integrative neuromuscular training on physical fitness and sport-specific performance in football players: A systematic review and meta-analysis

Reference: J Back Musculoskelet Rehabil. 2026 Feb 9:10538127261417735. doi: 10.1177/10538127261417735. Online ahead of print.
Authors: Xinrui Zhang, Kim G Soh, Yoke M Chan, Wenchao Rong, Yue Zhao, Xinzhi Wang
Summary: Integrative neuromuscular training (INT) is increasingly incorporated into football conditioning programs to improve neuromuscular function and athletic performance. However, its overall effectiveness across various aspects of physical fitness and sport-specific skills remains unclear. The aim was to systematically review and meta-analyze the effects of INT on physical fitness and football-specific performance outcomes in football players. Following PRISMA guidelines, this review was prospectively registered in PROSPERO (CRD420251052631). Comprehensive research was conducted in Web of Science, PubMed, SCOPUS, Embase, and CNKI up to May 2025. Methodological quality was evaluated using the TESTEX and ROB 2 tools, while the GRADE framework assessed evidence certainty. Where appropriate, random-effects model meta-analyses were applied. Twelve randomized controlled trials involving 276 football players of varying ages and competitive levels were included. INT produced significant improvements in lower-limb muscle strength (ES = 1.065; p < 0.001), power (ES = 0.453; p < 0.001), sprint speed (ES = -0.341; p = 0.001), agility (ES = -0.398; p < 0.001), balance (ES = -0.897; p < 0.001), and dribbling performance (ES = -1.028; p < 0.05). In contrast, shooting performance showed no significant improvement (ES = 0.324; p = 0.181). Notably, all effect estimates were supported by low-certainty evidence according to the GRADE assessment. INT may be associated with small-to-moderate improvements in strength, sprint speed, power, agility, balance, and dribbling compared with regular training; however, these findings are supported by low-certainty evidence and should be interpreted with caution. Future high-quality studies with standardized protocols are warranted to clarify its impact on advanced technical skills and optimize its integration into football training programs.

10 Somatotype, age, and neuromuscular performance in elite youth football players

Reference: J Sports Med Phys Fitness. 2026 Feb 9. doi: 10.23736/S0022-4707.25.17476-8. Online ahead of print.
Authors: Nikolaos Androulakis, Christos Tsiakiris, Nikolaos Koundourakis
Summary: Somatotype has been linked to physical performance in youth athletes, but its independent contribution to power development, particularly in relation to biological maturity, remains underexplored. This study examined whether somatotype and age independently influence neuromuscular performance in elite youth football players and whether these effects persist after normalization for body mass. A total of 106 elite male academy players aged 15 to 18 years were classified as mesomorphic or ectomorphic using the Heath-Carter method. Performance tests included vertical jumps from a squat position and with countermovement, lower-limb peak power (estimated via a validated field equation), and an index estimating stretch-shortening cycle efficiency. Relative power (W·kg-1) was also calculated to account for body-mass dependence. Analyses included multivariate and variance testing, to explore independent effects of somatotype and age. Mesomorphic players produced significantly higher power output than ectomorphic players; older athletes also exhibited greater power. No interaction was observed between somatotype and age group. However, when normalized to body mass, between-group differences were no longer significant, indicating that the apparent mesomorphic advantage reflected greater mass rather than superior neuromuscular efficiency. No significant somatotype effect was observed for the Elasticity Index (P=0.098). Logistic regression correctly classified 72.6% of somatotypes, but specificity for ectomorphs was very low (11.5%), indicating that power-based profiling is ineffective for identifying ectomorphic players. Somatotype and age independently influence power performance in elite youth football players. Nevertheless, relative power analysis demonstrated that morphological differences primarily underlie these effects. Power metrics alone lack diagnostic validity for morphological classification and should complement, rather than replace, anthropometric assessment.

11 Missing pieces, new patterns: the impact of association football international call-ups on team offensive and defensive performance indicators

Reference: Front Psychol. 2026 Jan 22:16:1697146. doi: 10.3389/fpsyg.2025.1697146. eCollection 2025.
Authors: João Campos, Bruno Gonçalves, Bruno Travassos, Nuno Mateus, Rafael Ballester Lengua, Bruno Figueira, Sigrid Olthof, Diogo Coutinho
Download link: https://pmc.ncbi.nlm.nih.gov/articles/PMC12872852/pdf/fpsyg-16-1697146.pdf
Summary: The aim was to examine how mid-season international call-ups (AFCON and AFC Asian Cup) affect club performance across offensive, defensive, and playing-style key performance indicators (KPIs). A non-participant observational study analyzed 522 league matches from 58 teams in Europe’s top five leagues (2023-2024). For teams losing players to international duty (n = 130 players across positions), club matches were grouped into three phases: PRE (three matches before), INT-CUP (three during absences), and POST (three after return). Wyscout-derived KPIs covered ball possession, goal scoring, offensive play, set pieces, and defensive actions. Non-parametric repeated-measures ANOVA (p < .05) and Cohen’s d quantified differences. INT-CUP showed clear improvements in ball-possession KPIs versus PRE and POST: higher total, successful, frontal, lateral, and backward passes; more progressive and deep completed passes; more crosses; and greater passes per possession, alongside shorter average passing length (all p ≤ .05; small-moderate effects). Goal-scoring output increased during INT-CUP (more shots, shots on target-including from outside the box-and goals vs PRE; more goals vs POST; p ≤ .05). Offensive penetration also rose (penalty-area entries and area touches; p ≤ .05), and positional attacks ending in shots were more frequent during INT-CUP (p = .015). Set-piece KPIs did not differ meaningfully. Defensively, PRE exceeded POST in duels, duels won, and defensive duels (p ≤ .05), while conceded goals were broadly unchanged across phases. Contrary to expectations, international absences coincided with a more possession-oriented style and enhanced attacking output, without compromising defensive outcomes. Effects between PRE and POST were modest, suggesting tactical adaptations during absences can sustain or even improve offensive efficiency. Coaches may leverage forced rotations to explore possession-based structures that preserve defensive stability.

12 Influence of Chronological Age, Anthropometric Characteristics and Biological Maturity on Eccentric Knee Flexion Strength During the Nordic Hamstring Exercise in Female International Youth Soccer Players

Reference: Eur J Sport Sci. 2026 Mar;26(3):e70135. doi: 10.1002/ejsc.70135.
Authors: Jack T Hickey, Tommy R Lundberg, Cian Sweeney, Áine MacNamara, Liam Sweeney
Summary: This study aimed to investigate the influence of chronological age, anthropometric characteristics and biological maturity on eccentric knee flexion strength during the Nordic hamstring exercise in female international youth soccer players. We included 50 under-15-year-old (chronological age = 14.1 ± 0.4 years) and 31 under-16-year-old (chronological age = 15.0 ± 0.5 years) female international youth soccer players as participants in this study. We measured each participant’s body mass, height and biological maturity expressed as the percentage of predicted adult height (PAH%). Each participant performed three maximal effort repetitions of the Nordic hamstring exercise on a field-based testing device (NordBord, VALD Performance, Brisbane, Australia) to measure their eccentric knee flexion strength. We used linear regression to investigate individual associations between eccentric knee flexion strength and each predictor variable (body mass, height, chronological age and PAH%). In addition, a partial least squares (PLS) regression model was developed to predict the average eccentric knee flexion strength. Eccentric knee flexion strength had statistically significant associations with body mass (p < 0.01 and R2 = 0.34), PAH% (p < 0.01 and R2 = 0.18) and chronological age (p = 0.03 and R2 = 0.06) but not with height (p = 0.11 and R2 = 0.03). The 2-component PLS model explained 36% of variance in eccentric knee flexion strength, with body mass and PAH% the most influential predictors. Body mass and biological maturation status should be considered when interpreting eccentric knee flexion strength testing results during the Nordic hamstring exercise in female youth soccer players as these factors appear more influential than chronological age or height in determining test performance.

13 Functional Design and Clinical Implications of Modern Soccer Footwear: A Comprehensive Narrative Review

Reference: J Funct Morphol Kinesiol. 2026 Jan 30;11(1):62. doi: 10.3390/jfmk11010062.
Authors: Andrea Demeco, Nicola Marotta, Marco Megna, Andrea Racinelli, Bruno Pansera, Antonio Frizziero, Ilona Yosypchuk, Stefano Palermi et al.
Summary: Soccer is the most widely practiced sport globally, but is also associated with a high incidence of lower limb injuries. Among multiple risk factors, soccer footwear represents a crucial biomechanical interface affecting traction, proprioception, and joint loading. This narrative review aims to explore how each component of modern soccer footwear impacts performance and injury risk, with a focus on evidence-based functional customization. A comprehensive narrative review of available literature was conducted across PubMed, Scopus, and Web of Science, integrating biomechanical, clinical, and materials science studies. We included studies concerning the structures composing soccer technical footwear. Conical studs were associated with reduced rotational stiffness and lower joint torque, while bladed studs enhanced linear traction but increased ACL strain risk. Upper materials, such as knitted fabrics and engineered mesh, improve proprioception and thermal regulation but show trade-offs in durability and protection. Soleplate stiffness influenced load distribution and performance: increased stiffness improves sprinting but compromises multidirectional agility. Fatigue and proprioception were modulated by insole and soleplate synergy. Soccer footwear should be seen as a clinical and performance tool requiring evidence-based customization. Advances in material technology, 4D foot scanning, and plantar pressure mapping enable functional matching between footwear and athlete characteristics. Translating these insights into player-specific footwear designs may reduce injury rates and enhance on-field performance.

14 Interrelationships and Shared Variance Among Three Field-Based Performance Tests in Competitive Youth Soccer Players

Reference: J Funct Morphol Kinesiol. 2026 Jan 29;11(1):58. doi: 10.3390/jfmk11010058.
Authors: Andrew D Fields, Matthew A Mohammadnabi, Oleg A Sinelnikov, Michael R Esco
Summary: Field-based testing is commonly used to evaluate key physical qualities related to soccer performance. However, limited research has examined the degree of shared variance among measures of aerobic capacity, change of direction (COD), and explosive power in youth athletes. This study investigated the relationships between the 20 m shuttle run (20MSR), T-test (TT), and vertical countermovement jump (CMJ) to determine their unique and overlapping contributions to each other’s performance in competitive youth soccer players. Twenty-five competitive male youth soccer players (13.7 ± 0.8 years) completed standardized assessments of TT, CMJ, and 20MSR during pre-season evaluations. Pearson correlations and hierarchical multiple regression analyses were used to examine associations and independent variance explained among the performance measures. Large, significant correlations were observed between TT and CMJ (r = -0.65, p < 0.001), TT and 20MSR (r = -0.59, p < 0.001), and CMJ and 20MSR (r = 0.53, p = 0.007). CMJ explained 42.3% of TT variance, whereas adding 20MSR did not significantly improve model fit (ΔR2 = 0.087, p = 0.062). Across models, aerobic capacity did not contribute significant unique variance beyond neuromuscular performance. COD and lower-body power share a common physiological foundation in youth soccer athletes, while aerobic capacity represents a distinct performance domain. When field tests are administered under applied conditions typical of youth soccer environments, TT and CMJ demonstrate substantial shared variance, whereas 20MSR remains largely independent. Therefore, the findings support the continued use of multi-modal testing batteries in practice.

15 Effects of concurrent training on speed and agility performance in soccer referees

Reference: Front Physiol. 2026 Jan 30:17:1768715. doi: 10.3389/fphys.2026.1768715. eCollection 2026.
Authors: Barış Baydemir, Zülbiye Kaçay, Laurentiu-Gabriel Talaghir, Paula Ivan
Summary: Soccer referees are exposed to high aerobic and anaerobic demands during match play, yet evidence regarding training strategies that simultaneously enhance speed and agility in this population remains limited. This study aimed to examine the effects of a 12-week concurrent training program on sprint and agility performance in soccer referees and to evaluate the sustainability of these effects through a follow-up assessment. To our knowledge, few intervention studies have simultaneously examined both sprint speed and agility performance in soccer referees and evaluated whether these adaptations are retained during a follow-up period. Importantly, the inclusion of a follow-up assessment provides evidence on the retention of training-induced adaptations, which has rarely been examined in referee populations under applied field-based training conditions. Fifty male soccer referees officiating in amateur leagues were assigned to a control group (n = 25) or an experimental group (n = 25). Both groups completed standard referee training twice weekly for 12 weeks, while the experimental group additionally performed concurrent training sessions combining endurance-based interval running and strength-power exercises twice per week. Sprint and agility performance were assessed using the 100 m sprint test and the Illinois Agility Test at pre-test, post-test, and 7-week follow-up. Data were analyzed using two-way mixed repeated measures ANOVA. Significant Group × Time interaction effects were observed for both sprint and agility performance (p < 0.01) with moderate-to-large interaction effects. The experimental group demonstrated greater improvements in 100 m sprint and Illinois Agility Test performance compared with the control group following the intervention. Importantly, these performance gains were largely maintained at follow-up, indicating sustained training adaptations. A 12-week concurrent training program integrated into standard referee conditioning resulted in significant and sustained improvements in speed and agility performance. These findings highlight the effectiveness of concurrent training as a multidimensional approach to enhancing physical capacities that are critical for soccer refereeing and support its practical implementation within referee training programs. These results support the integration of concurrent training into referee conditioning programs to improve movement efficiency and match positioning capacity. Practitioners may consider concurrent training as a feasible strategy to improve and maintain key physical qualities required for match positioning across competitive phases.

16 Relationships between four-directional postural deviations, lower extremity muscle strength, and anthropometric characteristics in soccer players

Reference: BMC Sports Sci Med Rehabil. 2026 Feb 20. doi: 10.1186/s13102-026-01610-2. Online ahead of print.
Author: Zeynep Inci Karadenizli
Download link: https://link.springer.com/content/pdf/10.1186/s13102-026-01610-2_reference.pdf
Summary: In sports such as soccer, which require sudden directional changes and single-leg stability, postural balance is a key determinant of performance. Insufficient knowledge regarding how balance levels influence directional changes and their potential relationship with injury risk remains a relevant practical problem in soccer. However, balance is often evaluated using single composite scores, while the relationships between directional postural deviations and central stability remain underexplored. Addressing this gap may improve the understanding of direction-specific balance demands in athletes. This study examined the associations between fourdirectional postural deviations and central stability obtained from a controlled dynamic single-leg postural stability test, and their relationships with lower extremity muscle strength and anthropometric characteristics. The applied methodology, incorporating anthropometric characteristics, was used to better approach this problem. A total of 95 male soccer players participated. Before interpretation, it is noted that lateral–medial and anterior–posterior deviation pairs are computed as proportional distributions by the device software; therefore, their strong inverse correlations (ρ = –1.00) reflect mathematical dependency rather than biomechanical opposition. Significant correlations were observed between height and both body weight (ρ = 0.68) and lower extremity muscle strength (ρ = 0.51). Height was positively associated with lateral postural deviation (ρ = 0.30). Central stability was positively associated with height (ρ = 0.50) and demonstrated moderate directional relationships with lateral (ρ = 0.44) and medial deviation (ρ = –0.44) (p < .01). In contrast, body weight and relative lower extremity strength showed weak or borderline associations with directional postural deviations. These findings suggest that postural control in soccer players exhibits directional organization influenced by anthropometric characteristics, indicating that individualized balance training approaches may be beneficial, particularly for optimizing direction-specific performance, while causal inferences cannot be made due to the cross-sectional design.

17 Return to sport after ACL reconstruction, meniscus and cartilage surgeries in professional soccer players: a systematic review and meta-analysis

Reference: Knee Surg Relat Res. 2026 Feb 19;38(1):6. doi: 10.1186/s43019-026-00304-w.
Authors: Riccardo D’Ambrosi, Jari Dahmen, Alessandro Carrozzo, Luca Maria Sconfienza, Christoph Kittl, Elmar Herbst, Christian Fink
Summary: The purpose of this systematic review and meta-analysis is to evaluate and compare the effects of anterior cruciate ligament reconstruction (ACLR), meniscal surgeries, and cartilage surgeries on return to sport (RTS) outcomes in professional soccer players. The methodology followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. An electronic database search was performed to identify potentially relevant research articles. Four different outcome measures (age at surgery, return to sport, time to return to sport, level of return to sport) were extracted and meta-analyzed from all included studies and compared from three different groups (ACLR, cartilage surgeries, meniscus surgeries). The pooled meta-analysis showed no difference in age at surgery among groups (p > 0.05). The overall pooled return-to-sport rate was 90% (95% CI 93.3-95.9), with no significant differences between ACL reconstruction, meniscus surgeries, and cartilage surgeries (p > 0.05) Patients treated for ACLR reported a longer time (p < 0.05) to return to sport (258.05 days; 95% CI 230.48-288.93) compared with meniscus (41.11 days; 95% CI 30.22-55.93) and cartilage surgeries (135.0 days; 95% CI 130.54-139.61). Furthermore, the pooled meta-analysis showed that athletes who underwent meniscus surgeries had a higher (p < 0.05) percentage of return to sport (100%: 95% CI 86.0-100.0) compared with ACLR (80.0%; 95% CI 67.5-90.3) and cartilage treatment (94.5%; 64.2-100.0). For professional soccer players, ACL reconstruction, meniscus surgeries, and cartilage surgeries demonstrated a favorable RTP rate of around 90%. Nevertheless, the analysis of the level of RTS and the time to RTS was constrained by limited evidence, precluding a more objective conclusion.

18 The influence of low and high spatial frequency visual information on the anticipation of soccer penalty kicks

Reference: Psychol Sport Exerc. 2026 Feb 17:84:103092. doi: 10.1016/j.psychsport.2026.103092. Online ahead of print.
Authors: James W Roberts, Kieran Harris, Tom Upshaw, Louise Gillen, Joe Causer, Simon J Bennett
Summary: Research on anticipation within sport has been recently advanced by the isolation of visual spatial frequencies. The present study seeks to adapt this body of work for the context of anticipating penalty kicks within soccer. Across two experiments, participants had to anticipate the direction of pre-recorded penalty kicks that were occluded at the point of ball contact. The penalty kicks were presented with low (LSF; ‚blurred‘), high (HSF; ‚edge detection‘ [i.e., sharp image outlines]) or unfiltered (i.e., original footage) spatial frequencies. Experiment 1 involved a lab-controlled setting using a life-sized display of the non-deceptive penalty kicks with outfield participants, which indicated no effect of visual condition. Experiment 2 involved a remote online protocol that displayed deceptive and non-deceptive penalty kicks with goalkeeper participants. While there was a decline in the anticipation of deceptive compared to non-deceptive kicks for the unfiltered condition, there was no such decline for the LSF and HSF conditions. We suggest that the LSF and HSF conditions were able to overcome deception because of the isolating global kinematic and local detailed cues, respectively.

19 A Comment on „Evaluating the Reliability and Seasonal Sensitivity of a Fitness-Testing Battery in Elite Youth Soccer“

Reference: Int J Sports Physiol Perform. 2026 Feb 16:1. doi: 10.1123/ijspp.2025-0600. Online ahead of print.
Author: Lorenzo Lolli
Download link: https://journals.humankinetics.com/view/journals/ijspp/aop/article-10.1123-ijspp.2025-0600/article-10.1123-ijspp.2025-0600.xml

20 The effects of whey protein supplementation on athletic performance and body composition in adolescent soccer players: a randomized controlled trial

Reference: Appl Physiol Nutr Metab. 2026 Jan 1:51:1-9. doi: 10.1139/apnm-2025-0325.
Authors: Grace A Zimmerman, Naomi Mmp de Hart, Isaac Z Ou, Victoria R Miranda, Eric D Bastian, Micah J Drummond, Christopher M Depner, Tanya M Halliday
Summary: Although protein supplementation is a common sports nutrition strategy, there is little research on its effects in adolescent athletes. Our objective was to assess the effects of whey protein supplementation on athletic performance and body composition in adolescent soccer players over a 10-week competitive soccer season. Adolescent athletes (n = 22; 59% female, age: 15.6 ± 0.2 [mean ± SEM] years; BMI percentile: 55.9 ± 6.2%) were randomized to consume either whey protein (PRO; n = 10; 20 g protein) or an isocaloric placebo (CON; n = 12) twice daily. Outcome measures included: estimated V̇O2max (1.5 mile run), sprint time (30 yard dash), muscle strength and endurance (quadricep isometric leg extension; maximum voluntary contraction and repetitions to fatigue, respectively), and body composition (fat mass and fat-free mass). Assessments were conducted at baseline and postintervention. V̇O2max improved in both groups (p < 0.001), with greater (p = 0.04) increases in the PRO versus CON group. Sprint time improved in both groups (p = 0.03), with no significant differences between groups. Muscle strength was similar across the study for both groups. Muscular endurance declined in the PRO group compared to CON (p = 0.01). Fat-free mass increased in both groups (p = 0.02), whereas fat mass was unchanged. Our results indicate that whey protein supplementation during the competitive season in adolescent athletes improved V̇O2max compared to control. However, whey protein did not lead to improvements in sprint performance, musculoskeletal fitness, and body composition compared to control.

21 Energy production pathways of female soccer players during championships: a metabolomics approach

Reference: Braz J Med Biol Res. 2026 Feb 16:59:e14589. doi: 10.1590/1414-431X2025e14589. eCollection 2026.
Authors: M B A Nascimento, M M S Gouveia, M P P Santos, E R da Rocha-Junior, A C Crispim, E S Bento, T M Aquino, F A B Sousa, G G de Araujo, T Ataide-Silva
Download link: https://www.scielo.br/j/bjmbr/a/zf6dpgnryHHCph9yFcrhCrn/?format=pdf&lang=en
Summary: Athletes mobilize both aerobic and anaerobic systems to produce energy during soccer matches, and it drastically modifies the concentration of metabolites related to muscle damage and energy metabolism. The fatigue-associated mechanism seems to encompass tricarboxylic acid cycle (TCA) disturbances, with a greater contribution of lipid-pathway metabolites in women during soccer matches. However, to the best of our knowledge, the effects of matches played during two championships on the metabolites and pathways associated with energy production in female players have not yet been described. Metabolomic analysis in sports context can better characterize the main metabolites related to energy production and the metabolic pathways. The aim of this study was to describe the variation in metabolites over the course of two championships in female players‘ urine, highlighting the occurrence of energy production-associated metabolites and the metabolic pathways they may arise from. Urine samples were collected before and after six matches of two championships. Nuclear magnetic resonance metabolomic approach was used for this purpose. Citrate, succinate, 1-methylnicotinamide, alpha-hydroxyisobutyrate, malonic and glycolic acids, phosphocreatine, and lactate were the compounds originated from energy generation processes with high scores in variable importance prediction (VIP), impacting on partial least squares discriminant analysis (PLS-DA) groupings of players. Phenylalanine biosynthesis, tyrosine and tryptophan biosynthesis, and the TCA cycle were mobilized before the matches, and the metabolism of taurine and hypotaurine were modulated across both moments.

22 Comparative effects of static stretching, PNF, MET, Graston, and foam rolling on hamstring flexibility in adolescent soccer players: a randomized controlled trial

Reference: BMC Sports Sci Med Rehabil. 2026 Feb 19. doi: 10.1186/s13102-026-01566-3. Online ahead of print.
Authors: Seyed Mohammad Hosseini, Hossein Rezaei, Shokoohe Razmjoo
Download link: https://link.springer.com/content/pdf/10.1186/s13102-026-01566-3_reference.pdf
Summary: Abstract Background & Purpose: One of the common injuries in soccer is hamstring strain, so improving hamstring flexibility can partially prevent the occurrence of these injuries. The aim of the present study was to compare the effects of six weeks of static stretching (SS), proprioceptive neuromuscular facilitation (PNF), muscle energy technique (MET), gross tonic technique (GT), and foam rolling (FR) on hamstring flexibility in adolescent male soccer players. Methods: Ninety male soccer players (mean aged= 13.01±1.11 years) were randomly assigned to five intervention groups and a control group (n=15 each), underwent a 6-week intervention, with flexibility assessed pre- and post-intervention using a universal goniometer and the active knee extension test. Results: One-way ANCOVA, controlling for pretest values, showed a significant difference between groups (F(5, 83) = 22.79, p < 0.001, η² = 0.57). All intervention groups showed significant improvement compared to control (p0.05; Cohen’s d = −0.75). Conclusion: All methods improved hamstring flexibility, but GT was the most effective (except when compared with SS). These findings suggest the potential use of GT in training programs to reduce injury and improve performance in adolescent soccer players. However, since the study included only adolescent male players and no long-term follow-up was performed, generalizability is limited.