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 The Effects of Motor-Cognitive Warm-Up Protocols on Sport-Specific Skills in 8-Year-Old Football Players

Reference: Sports (Basel). 2025 Nov 25;13(12):416. doi: 10.3390/sports13120416.
Authors: Sayyedarmin Ganji, Hamidreza Sepehri Rahnama, Sára Németh, Dominika Jantal, Kitty Vadasz, Judit Prokai
Download link: https://pmc.ncbi.nlm.nih.gov/articles/PMC12737191/pdf/sports-13-00416.pdf
Summary: Football is a multifaceted sport in which cognitive function plays a crucial role alongside physical performance in overall athletic success. However, widely adopted warm-up protocols primarily target motor skills, with minimal attention to cognitive readiness. This study aimed to investigate the short-term effects of motor-cognitive warm-up protocols incorporating auditory and visual stimuli on various cognitive and motor skills in youth male football players. Twenty-four male players (age = 8.56 ± 0.33 years) were randomly assigned to three groups (n = 8): motor-verbal (MVEG), motor-visual (MVIG), and motor-only. Each player completed one warm-up session followed by four performance tests. All groups completed the same football-specific warm-up exercises, differing only in instruction modality: pre-given for MG, verbal (auditory) for MVEG, and visual for MVIG. Immediately after the warm-up, participants completed the Stroop Color-Word Test (SCWT), Loughborough Soccer Passing Test (LSPT), Illinois Ball Test (IBT), and t-test. Significant group differences were found in SCWT error rate (p = 0.009), LSPT time (p = 0.001), IBT time (p = 0.036), and t-test time (p = 0.003). Across these tests, seven outcome measures were recorded: SCWT completion time and error rate, LSPT total time (finishing time plus penalties), IBT completion time and error rate, and t-test completion time. No differences were observed in SCWT completion time or IBT error rate. MVEG outperformed the other groups in most tests, except the LSPT, where MVIG achieved the best performance. MG showed the lowest overall performance, except in the t-test. Warm-up protocols incorporating cognitive stimuli can immediately improve motor and executive performance.

2 Comparison of Training Effects of Bounding and Single Leg Jumps for Speed on Sprint and Jump Kinematics in Young Female Football Players

Reference: J Funct Morphol Kinesiol. 2025 Dec 2;10(4):468. doi: 10.3390/jfmk10040468.
Authors: Bjørn Johansen, Jonathon Neville, Roland van den Tillaar
Download link: https://pmc.ncbi.nlm.nih.gov/articles/PMC12733884/pdf/jfmk-10-00468.pdf
Summary: This study compared the training effects of two horizontal plyometric training interventions over six weeks on sprint performance and jump kinematics in young female athletes.  Nineteen female football players (age 15.3 ± 0.5 years) were stratified by sprint time into a bounding for speed group (n = 10) or a single leg jumps for speed group (n = 9). All participants completed pre- and post-tests including a 40 m sprint, bounding, and single leg jumps for speed with both legs. Sprint times and velocities over 10 m, 20 m, and maximal speed were recorded, and jump kinematics (horizontal velocity, step length, and step frequency) were analyzed.  A significant main effect of time was found for sprint performance, indicating that both groups improved overall. The single-leg jump group showed significant within-group improvements across all sprint measures (10 m, 20 m, maximal velocity, and 40 m time) and significant increases in horizontal velocity and step length during the single-leg jump with both legs. The bounding group showed no significant sprint improvements, with only a within-group increase in step frequency during bounding and a trend toward shorter step length (p = 0.037, ηp2 = 0.40).  Both training groups improved sprint performance overall, but only the single-leg jump group showed consistent within-group gains in both sprint and jump performance. These findings suggest that single-leg jumps for speed may be a practical and effective option for developing sprint-related qualities in young female football players, although the differences between groups should be interpreted with caution.

3 Influence of Anticipation on Neuromuscular Control During a Single-Leg Diagonal Drop Jump Landing Task In Female Football Players. A Cross-Sectional Study

Reference: Eur J Sport Sci. 2026 Jan;26(1):e70097. doi: 10.1002/ejsc.70097.
Authors: A Miralles-Iborra, T Dos’Santos, J L L Elvira, M Esteban-López, J Del Coso, V Moreno-Pérez
Download link: https://pmc.ncbi.nlm.nih.gov/articles/PMC12724577/pdf/EJSC-26-e70097.pdf
Summary: The impact of anticipation during a football-specific action on neuromuscular control in female football players is underexplored. To investigate the influence of anticipation on trunk and lower limb kinematics during a single-leg diagonal drop jump test in female football players. Twenty-eight amateur football players performed two drop jumps per leg in two directions: ipsilateral and contralateral (same or opposite side of the landing leg, respectively) under anticipated and unanticipated conditions. In the anticipated condition, the jump direction was known before landing, whereas in the unanticipated condition, it was indicated by a visual light stimulus presented before ground contact. The sagittal and frontal planes of the first landing were recorded for 2D video analysis. Female football players exhibited longer ground contact time (p < 0.001; ES = 1.649-1.798) during unanticipated jumps. Unanticipated trials were performed with greater trunk, hip and knee flexion, and this was already evident at initial contact (ηp 2 ≈ 0.16-0.18) and became very large by final contact (ηp 2 ≈ 0.60-0.69). Trunk lateral flexion and hip abduction decreased during unanticipated ipsilateral jumps (p ≤ 0.005; ES = 0.83-1.76) but increased during unanticipated contralateral jumps (p ≤ 0.002; ES = -0.67-[-1.74]). Additionally, the medial knee position increased in unanticipated ipsilateral jumps (p < 0.001; ES = -1.89) but decreased in unanticipated contralateral jumps (p = 0.005; ES = 0.62). Unanticipated landings increase ground contact time, promote flexed sagittal strategies and affect frontal kinematics differently influenced by the subsequent jump direction in female football players.

4 More than a whistle: examining the role of organizational culture and talent development in football referee progression

Reference: Front Psychol. 2025 Dec 5:16:1701987. doi: 10.3389/fpsyg.2025.1701987. eCollection 2025.
Authors: Anthony Taylor, Mark Batey, Danny Powell, Abhijeet Patra, Andrew Denovan, Neil Dagnall
Download link: https://pmc.ncbi.nlm.nih.gov/articles/PMC12715820/pdf/fpsyg-16-1701987.pdf
Summary: Talent development is a foundational process that enables performance, facilitates the realization of potential, and promotes positive engagement with growth opportunities. In the context of football, this is important to referee bodies because of the need to attract, retain, and progress officials. Noting high referee attrition and a shortage of elite officials, this study examined how conscientiousness, mental toughness, and organizational culture influenced referees‘ perceptions of talent development. One hundred and eighty-one referees, categorized by the highest level at which they had officiated, completed self-report measures. Analysis revealed a significant main effect of referee level on perceptions of talent development. Officials at intermediate level 4 reported a specific drop in talent development, particularly in Holistic Quality Preparation (integrated development) and Support Network (availability of assistance), indicating a developmental bottleneck. Further comparisons among the most experienced officials found that while conscientiousness and mental toughness did not differ, Super-Elite (i.e., international medal winning) versus Elite (i.e., high ranking) referees held significantly more positive perceptions of organizational culture and talent development. Thus, while a baseline level of psychological resources is essential for officiating, perceived quality of organizational environment distinguishes between those at the highest levels of refereeing.

5 Understanding how athlete engagement is associated with adolescent mental health: Evidence from a longitudinal football study

Reference: J Affect Disord. 2025 Dec 18:398:120933. doi: 10.1016/j.jad.2025.120933. Online ahead of print.
Authors: Huarui Huang, Chen Zhong, Xiaoqi Sha, Xuan Wang, Yizhou Shui, Xuqun You
Summary: This study aims to examine the potential pathways linking athlete engagement and adolescent mental health within the Dual-Factor Model of mental health. A longitudinal survey was conducted among Chinese adolescents at three time points: baseline (Time 1; n = 794), three months later (Time 2; n = 684), and six months later (Time 3; n = 615). Athlete engagement in football was assessed with the Athlete Engagement Questionnaire. Adolescents‘ mental health was measured using the Rosenberg Self-Esteem Scale and the Self-Rating Depression Scale. Cross-Lagged Panel Models were estimated to test bidirectional associations, longitudinal mediation and gender difference. The analyses revealed significant bidirectional associations between athlete engagement and both self-esteem and depression. Self-esteem mediated the bidirectional association between athlete engagement and depression, and depression mediated the bidirectional association between athlete engagement and self-esteem. Multi-group analyses showed clear gender differences. Among males, depression fully mediated the bidirectional association between athlete engagement and self-esteem. Among females, self-esteem fully mediated the bidirectional association between athlete engagement and depression. The traditional Cross-Lagged Panel Models does not isolate within-person effects. Reliance on self-reports and a single regional sample may limit generalizability. These findings indicate multiple bidirectional pathways which differed by gender between athlete engagement and both the positive and negative dimensions of adolescent mental health. This supports gender-specific interventions for adolescent mental health and to foster a positive cycle in which sports supports well being.

6 Isokinetic evaluation of knee muscles and correlation of maximum torque of the extensors of the operated knee with thigh circumference in soccer players 2 years after ACL reconstruction: A cross-sectional study

Reference: Hong Kong Physiother J. 2025 Dec;45(2):119-130. doi: 10.1142/S1013702525500106. Epub 2025 Apr 30.
Authors: Konstantinos Chatzilamprinos, Eleni Semaltianou, Dimitrios Lytras, Evaggelos Sykaras
Summary: Anterior cruciate ligament reconstruction (ACLR) often results in residual strength deficits in knee muscles, which may affect an athlete’s return to performance. Isokinetic testing and thigh circumference measurements offer valuable insights into recovery, with thigh circumference potentially serving as a quick indicator of quadriceps strength. The aim was to evaluate the isokinetic capability of knee extensors and flexors two years after ACLR and examine the correlation between isokinetic peak torque of knee extensors and thigh circumference of the operated limb. Seventeen professional soccer players, two years post-ACLR, participated. Thigh circumference was measured at 10 cm and 20 cm from the patella. The peak torque of knee flexors and extensors was assessed at various speeds. Hamstring-to-quadriceps ratios (H/Qconv and H/Qfunc) were evaluated. Paired-Samples T Test compared peak torque, thigh circumference, H/Qconv, and H/Qfunc between limbs. Pearson Correlation determined the relationship between peak torque of knee extensors and thigh circumference. Two years post-ACLR, peak torque was significantly reduced for knee extensors at 60∘/s, 180∘/s, and 300∘/s ( p<0.05 ) and for knee flexors at 60∘/s ( p=0.038 ). No significant differences were found for H/Qconv and H/Qfunc. Thigh circumference differed significantly at 20 cm from the patella ( p=0.030 ) and correlated with the peak torque of knee extensors ( r=0.770 -0.863). Knee extensors and flexors show reduced peak torque two years post-ACLR. A strong correlation exists between peak torque of knee extensors and thigh circumference. Isokinetic evaluation is effective at functional velocities, and thigh circumference measurement is a viable alternative for assessing quadriceps strength.

7 Popliteal Entrapment in a 16-Year-Old Soccer Player Treated via Detachment and Repositioning of the Medial Head of the Gastrocnemius

Reference: Case Rep Orthop. 2025 Dec 19:2025:6625479. doi: 10.1155/cro/6625479. eCollection 2025.
Authors: Thomas Bane, Nadia Nawabi, Kirk Hance, Jacob Brubacher
Download link: https://pmc.ncbi.nlm.nih.gov/articles/PMC12747087/pdf/CRO-2025-6625479.pdf
Summary: Popliteal artery entrapment syndrome (PAES) is a frequently underdiagnosed disease in young patients due to its low incidence and nonspecific symptoms. The disease is classified broadly into two categories: anatomic entrapment or functional entrapment. Prompt diagnosis is crucial due to the potentially limb-threatening nature of this condition should critical limb ischemia develop. A 16-year-old male soccer player with no past medical history who had 1 week of acute onset right lower extremity calf pain and foot numbness due to right proximal popliteal and tibial artery occlusion in the setting of Type 1 popliteal artery entrapment. Treatment initially included thrombolysis but was complicated by development of compartment syndrome requiring emergent four-compartment fasciotomy. He subsequently underwent thrombectomy of his popliteal, anterior, and posterior tibial arteries before definitive popliteal artery decompression with medial gastrocnemius recession and repositioning. PAES is a rare disease that can lead to devastating complications such as critical limb ischemia as seen in this patient. It is of paramount importance to identify this disease early and implement appropriate treatment. Debate remains as to the necessity of bypass or vascular repair in patients with Type 1 PAES. This patient did not undergo popliteal artery bypass and has been doing well postoperatively thus far.

8 Diagnosis, Rehabilitation, and Training Load Monitoring Following Hematogenous Calcaneal Osteomyelitis in a Competitive Adolescent Soccer Player: A Level 4 Case Report

Reference: J Athl Train. 2025 Dec 23;60(12):857-862. doi: 10.4085/1062-6050-0207.25. eCollection 2025 Dec.
Authors: Erik A Wikstrom, Stuart L Mitchell, Joshua N Tennant, Heather Carroll, April M Wikstrom
Download link: https://nata.kglmeridian.com/meridian/nata/published/rest/pdf-watermark/v1/journals/attr/60/12/article-p857.pdf/watermark-pdf/
Summary: A 13-year-old male competitive club soccer player with a history of bilateral Osgood-Schlatter disease over the past 6 months reported unusually high fatigue and right heel pain after a match. Over the next 4 days, fever developed and persisted despite antipyretics. Right heel pain, warmth, and redness increased until weight-bearing was not tolerated. Subsequent imaging and blood work eventually lead to a calcaneal osteomyelitis diagnosis. A bone biopsy procedure and a 6-week course of antibiotics were completed. The rehabilitation and conditioning plan, which was successful, was based on assessment findings and targeted a return to sport 12 weeks postsurgery. Interprofessional collaboration was key for the diagnosis and effective medical treatment. Rehabilitation and conditioning protocol development was challenging as (1) no postsurgical rehabilitation protocol for a patient with calcaneal osteomyelitis wishing to return to sport has been described and (2) the impact of postinjury rehabilitation on training load is poorly documented.

9 Casein Supplementation Timing and Exercise Performance in Soccer Players: Pre-Sleep vs. Post-Exercise Intake-A Randomized Controlled Trial

Reference: Nutrients. 2025 Dec 17;17(24):3938. doi: 10.3390/nu17243938.
Authors: Serdar Bayrakdaroğlu, Zeynep Hazal Ateş, Halil İbrahim Ceylan, Murat Kul, Raul Ioan Muntean, Wissem Dhahbi
Download link: https://www.mdpi.com/2072-6643/17/24/3938
Summary: Nutrient timing strategies may influence recovery and performance in athletes; however, the effects of ingesting casein protein before sleep versus immediately after exercise remain unclear. This study compared the acute effects of pre-sleep and post-exercise ingestion of casein on high-intensity anaerobic performance in highly trained soccer players.  Twenty-four highly trained male soccer players (mean age: 20.6 ± 1.8 years) were randomly assigned to three groups: post-exercise casein ingestion group (PECIG; n = 8), pre-sleep casein ingestion group (PSCIG; n = 8), and control group (CG; n = 8). Following a standardized high-intensity resistance training protocol, participants consumed 30 g of micellar casein dissolved in 300 mL of water either immediately after exercise or 30-60 min before bedtime. Performance was assessed using the Countermovement Jump (CMJ), the Illinois Agility Test (IAT), and the Running-based Anaerobic Sprint Test (RAST), which were conducted both before and 24 h after the training session. Repeated-measures ANOVA revealed significant group-by-time effects for CMJ (F = 8.21, p = 0.002, η2p = 0.36) and RAST performance variables, including peak power (F = 6.94, p = 0.003, η2p = 0.32), mean power (F = 7.42, p = 0.002, η2p = 0.34), and fatigue index (F = 5.87, p = 0.008, η2p = 0.28). Post hoc analyses showed that PSCIG significantly improved CMJ (Δ = +1.45 cm; p < 0.001, d = 2.04) and RAST mean power (Δ = +125.14 W; p = 0.002, d = 1.55) compared with the control condition. PECIG significantly enhanced RAST peak power (Δ = +205.79 W; p = 0.001, d = 1.64), mean power (Δ = +128.43 W; p = 0.013, d = 1.24), and fatigue index (Δ = +4.12 W/s; p = 0.010, d = 1.29) relative to CG. No performance differences were observed between PSCIG and PECIG timing conditions (all p > 0.05).  Both pre-sleep and post-exercise casein ingestion enhanced anaerobic performance in highly trained soccer players, with each timing method favoring different performance outcomes. However, neither strategy demonstrated superiority over the other, suggesting that casein timing may be flexibly applied according to athletes‘ preferences and training contexts.

10 Precision Training Via Causal Machine Learning: Modeling Rating of Perceived Exertion in Professional Soccer Players

Reference: Int J Sports Physiol Perform. 2025 Dec 9;21(1):137-147. doi: 10.1123/ijspp.2024-0537. Print 2026 Jan 1.
Authors: Tom Van Deuren, Thomas Decorte, Peter Catteeuw, Steven Latré, Tim Verdonck
Summary: This study aimed to explore the use of predictive and prescriptive machine-learning models for managing training loads in professional soccer, with a focus on the rating of perceived exertion (RPE). Using data from a Belgian Pro League club, we evaluated the effectiveness of these models in predicting and prescribing optimal training regimens. Data from 14 players across a full competitive season were analyzed. Predictive models including linear regression, random forest, and XGBoost were compared using the root-mean-square error and the mean absolute error. SHapley Additive exPlanations values were used to interpret feature importance. A prescriptive model based on the counterfactual recurrent network was developed to optimize training inputs for desired outcomes. The XGBoost model demonstrated the best predictive performance (root-mean-square error: 1.262), with session distance identified as the most significant driver of RPE. While the prescriptive counterfactual recurrent network model showed slightly lower predictive accuracy (root-mean-square error: 1.379), its unique advantage lies in estimating counterfactual outcomes, allowing for the simulation of future RPE trajectories under different potential training plans and providing actionable insights for personalized training prescription. Predictive modeling effectively estimates RPE, and prescriptive modeling offers the added benefit of optimizing training strategies. The integration of these approaches supports data-driven decisions in professional soccer, enhancing player performance and recovery. Future research should expand sample sizes and validate these methods across diverse sports and contexts.

11 Is Weekly Training Load Associated With Match-Related Contextual Variables in Spanish Elite Young Soccer Players?

Reference: Pediatr Exerc Sci. 2025 Dec 29:1-8. doi: 10.1123/pes.2024-0098. Online ahead of print.
Authors: Vicente de Dios-Álvarez, Alexis Padrón-Cabo, Julen Castellano, Ezequiel Rey
Summary: Monitoring weekly training load (WTL) is essential in youth soccer; however, the influence of contextual factors on WTL during the microcycle remains unclear. The aim of this study was to (1) analyze the effect of match-related contextual factors, such as match location, and opponent standard on WTL in elite youth soccer players across a competitive season, and (2) compare session and WTLs according to the number of training sessions per microcycle. Training and match data were collected from 46 male soccer players of a Spanish First Division academy. External load variables were obtained using Global Positioning System, including total distance covered, high-speed distance (>18 km·h-1), sprint distance (>21 km·h-1), the number of high metabolic load efforts (>20 W·Kg-1), and player load. Training weeks were categorized based on contextual factors, such as match location, opponent level, and the number of training sessions in the microcycle (3, 4, or 5 sessions per week, W3s, W4s, W5s, respectively). WTL significantly increased (P < .05) in sprint distance weeks before playing away compared with playing at home. In reference to the length of the microcycle, W3s showed a significant decrease (P < .01) in WTL than W4s and W5s in all metrics. Additionally, W5s had significantly greater WTL for total distance covered, player load, and power score than W4s (P < .01). Match location was the only contextual factor affecting WTL, highlighting the importance of considering its impact when planning training load, as it may influence recovery, fatigue, and overall training strategies.

12 Workload Quantification in Women’s Soccer: Does the Starting Status Classification Matter?

Reference: Int J Sports Physiol Perform. 2025 Dec 12:1-9. doi: 10.1123/ijspp.2025-0315. Online ahead of print.
Authors: Carlos-Efrain Miranda-Gonzalez, Vincenzo Rago, Fabio Y Nakamura, Juan J Fernández-Romero, Miguel Saavedra-García
Summary: This study explored methodological considerations in comparing accumulated workload across different starting status classification methods in professional women’s soccer. Specifically, we (1) described best-fit classification criteria and (2) compared accumulated workload data across methods used to categorize players based on the previous match exposure. Workload data were collected from 36 soccer players competing in the Mexican Women’s League over 3 seasons, covering 240 training sessions and 51 matches. Workload metrics were obtained using global positioning system, heart-rate recording, and ratings of perceived exertion. Players were classified as starters or nonstarters according to seasonal available playing time (SAPT; >60% total match time), weekly playing time of the last match (WPTLM; ≥60 min), and weekly match started (WMS). The players‘ classifications matched 71.4% between SAPT and WPTLM and 90.0% between WPTLM and WMS. Among starters, the strongest agreement occurred between WPTLM and WMS (73.3%), whereas nonstarters showed the largest discrepancy between WMS and SAPT (74.2%). In all scenarios, players had a higher likelihood of being classified as nonstarters (odds ratio = 1.17-1.74). The SAPT method (60-min cutoff) best predicted starting status (R2 = .52). In general, either in starters or in nonstarters, seasonal accumulated workload differed across classification methods for almost all metrics (P < .05). Classifying players based on WPTLM or WMS produced similar workload outcomes, being suitable for immediate week-to-week decisions to balance the training in women’s soccer. On the other hand, the SAPT is more suitable for retrospective use (previous seasons and research).

13 ACL Injuries in Major League Soccer: A 10-Year Analysis of Injury Rate and Return to Play, and Performance Metrics by Player Position

Reference: Orthop J Sports Med. 2025 Dec 22;13(12):23259671251399842. doi: 10.1177/23259671251399842. eCollection 2025 Dec.
Authors: Brian Forsythe, Catherine Hand, Camden Bohn, Francis Hand, Vahram Gamsarian, Daanish Khazi-Syed, Joshua Chang, Vikranth Mirle, Eric Giza, Robert Brophy, Danyal Nawabi, Bert Mandelbaum
Download link: https://pmc.ncbi.nlm.nih.gov/articles/PMC12743941/pdf/10.1177_23259671251399842.pdf
Summary: Anterior cruciate ligament (ACL) injuries are among the most debilitating injuries in professional soccer, often leading to extended recovery times and performance impacts. While much is known about ACL injury outcomes in European leagues, data specific to the Major League Soccer (MLS) remains limited. This study aimed to assess the return to play (RTP) times, RTP rates, and performance outcomes after ACL reconstruction in MLS athletes. It was hypothesized that RTP times would improve over the study period and that player performance would stabilize by the third post-injury season, consistent with findings from other professional soccer leagues. The MLS Injury Surveillance database was queried for ACL injuries from 2010 to 2021. Player characteristics, injury characteristics, and performance metrics were collected for 132 players with ACL injuries and compared with 396 uninjured controls matched by age, position, and seasons played. The injured cohort was divided into 2 groups: 2010-2015 and 2016-2021 to compare changes in RTP times, performance outcomes, and trends over time. RTP was defined as participation in at least 1 MLS match after injury. Statistical analyses, including the chi-square and t tests, were performed to evaluate differences between the 2 time periods and matched controls, with significance set at P < .05. RTP time decreased significantly from 269.6 days (2009-2015) to 219 days (2016-2021) (P = .044). Forwards experienced significant performance declines starting in the third post-injury year, with reductions in goals scored, minutes played, and offsides (P < .05). Midfielders showed improved performance in goals scored by the third post-injury year, while defenders exhibited recovery by the second year, with no significant long-term performance deficits. Our study demonstrated that while overall RTP times have improved, position-specific performance outcomes vary significantly, with forwards exhibiting long-term deficits compared with midfielders and defenders. These findings suggest that position-specific rehabilitation protocols may be beneficial for athlete education in RTP and for potential prevention strategies.

14 Combined effects of verbal encouragement and motivational music on anaerobic performance in young soccer players: A randomized controlled trial

Reference: Medicine (Baltimore). 2025 Dec 26;104(52):e46565. doi: 10.1097/MD.0000000000046565.
Authors: Houda Bougrine, Imed Gandouzi, Nidhal Nasser, Halil İbrahim Ceylan, Noureddine M Ben Said, Mohammed Issa Alsaeed, Valentina Ștefănică, Amine Souissi, Rabii Djobbi, Ismail Dergaa, Nasr Chalghaf
Download link: https://pmc.ncbi.nlm.nih.gov/articles/PMC12746924/pdf/medi-104-e46565.pdf
Summary: Anaerobic performance is crucial for soccer success, yet optimal pre-competition strategies for young athletes remain unclear. Both verbal encouragement and motivational music have shown independent benefits, but their combined effects in pediatric populations are understudied, limiting evidence-based performance enhancement approaches. To investigate the individual and combined effects of verbal encouragement and self-selected motivational music on anaerobic performance metrics in young soccer players. Twenty-eight male soccer players (age: 8.46 ± 0.64 years) completed a randomized crossover study with 4 conditions: placebo control with silent headphones and no verbal encouragement; music only with self-selected motivational music; verbal encouragement only with silent headphones; and combined music plus verbal encouragement. Performance was assessed using medicine ball throw test, sprint tests (5 m, 10 m, 20 m), modified agility T test, and Illinois agility tests with and without ball. All sessions were separated by at least 72 hours with standardized warm-up protocols. All 3 intervention conditions significantly enhanced performance compared to placebo across all measures (P ≤ .002). The combined condition demonstrated superior performance compared to individual interventions (P ≤ .002). Verbal encouragement alone showed marginally greater effects than music alone, reaching statistical significance in Illinois agility tests, modified agility T test, and 5 m/10 m sprints (P = .006-.001). Effect sizes were largest for the combined intervention across all performance parameters. Combined verbal encouragement and motivational music provides optimal anaerobic performance enhancement in young soccer players, suggesting coaches should integrate both strategies during pre-competition preparation. These findings support evidence-based multimodal approaches for youth athlete development, with immediate applications for training protocols and talent identification programs in pediatric sports medicine.

15 The training and development process during childhood and adolescence of a multiple Ballon d’Or-nominated soccer player

Reference: Front Sports Act Living. 2025 Dec 11:7:1710194. doi: 10.3389/fspor.2025.1710194. eCollection 2025.
Authors: Espen Tønnessen, Silvana Bucher Sandbakk, Sigmund Apold-Aasen, Øyvind Sandbakk, Thomas A Haugen
Download link: https://pmc.ncbi.nlm.nih.gov/articles/PMC12738862/pdf/fspor-07-1710194.pdf
Summary: Information regarding the training and development of youth talents who successfully progress to professional soccer remains both limited and contradictory. The aim of this study was to retrospectively investigate the training and development process of a world-class soccer player during childhood and adolescence. An intrinsic case study design was employed to capture the quantitative and qualitative aspects of the training and development process. A four-step data collection procedure was used, along with pragmatic analyses of (1) training history based on logs and plans, (2) in-depth semi-structured interviews with the player’s father, who also served as head coach throughout the analyzed period, (3) follow-up interviews to clarify, expand upon, or validate findings from steps 1 and 2, and (4) systematic quality assurance through triangulation and negotiation among researchers and key informants, including the player. During childhood and adolescence, the player engaged in approximately 1,000-1,300 h of soccer training annually. Unorganized training constituted most of this time, though its proportion gradually declined as the volume of organized training increased. The unorganized training conducted with his father was guided by a clear philosophy: Basic technical skills were learned through isolated and targeted drills in form of ball control, passing, receiving, feints, visual exploration and scanning. These foundational skills were reinforced and refined in game-realistic settings during unorganized play with friends on the local turf, and ultimately, through match play. As the player progressed, increasingly complex tasks were introduced. He received personalized challenges that matched his current skill level and supported further development. Key developmental factors contributing to his success included a multidimensional motor talent, an exceptional passion for soccer and a strong willingness to train, a learning-oriented mindset, training with 1-3-year older peers, a supporting and knowledgeable father, and year-round access to high-quality training facilities. The novel insights reported here may serve as a basis for reflection when players and coaches consider how they should optimize the long-term development and performance. However, the unusually high training volumes described here should not be interpreted as general recommendations for average youth players or non-elite settings.

16 Expanding our understanding of talent development environments in English female youth football: Player, parent and coach perspectives

Reference: J Sports Sci. 2026 Jan 2:1-9. doi: 10.1080/02640414.2025.2604931. Online ahead of print.
Authors: Stacey Emmonds, Adam Gledhill, Tom Mitchell, Andreas Ivarsson, Barnaby Sargent-Megicks
Summary: Female football is one of the largest growing sports in the world; yet there is comparatively little research exploring female football talent development environments (TDEs). To develop understanding of TDEs, we explored and compared players‘, parents‘ and coaches‘ perspectives of TDEs, and provide suggestions regarding opportunities for development. Using a cross-sectional design, we surveyed – using the Talent Development Environment Questionnaire-5 (TDEQ-5) – 3217 participants (players n = 1456; parents n = 1432; staff n = 329) from 30 English female football TDEs. Descriptive subscale analysis revealed largely positive perceptions of TDEs (>4/6 of each subscale). Coaches had more positive perceptions of the TDEs than players and parents in all TDEQ-5 subscales, except for the alignment of expectations subscale where coaches had the least positive perception. Significant differences between players, coaches, and parents (p ≤ 0.001) were evident across the support network (coaches most positive, then parents, then players) and alignment of expectations (parents most positive, then players, then coaches) subscales. Based on lowest scoring items from players, coaches and parents, we themed key opportunities for development under (1) achievement-related communication, (2) success planning, and (3) coping skills. Findings can provide direction to national policy makers and inform coach and parent education initiatives.

17 Menstruation and injury occurrence; a four season observational study in elite female football players

Reference: Front Sports Act Living. 2025 Dec 16:7:1665482. doi: 10.3389/fspor.2025.1665482. eCollection 2025.
Authors: E Ferrer, N Keay, L Balagué-Dobón, A Cáceres, P Jarrin, G Rodas, J R González
Download link: https://www.frontiersin.org/journals/sports-and-active-living/articles/10.3389/fspor.2025.1665482/full
Summary: The menstrual cycle has been hypothesized to influence injury risk in female athletes due to hormonal fluctuations affecting musculoskeletal, metabolic, and neuromuscular systems. However, methodological inconsistencies and variability in phase classification have resulted in conflicting evidence. The lack of biological samples forces researchers to estimate and speculate about the relationship between the menstrual cycle and injury risk. It is well established that each phase of the cycle is characterized by specific hormonal profiles with distinct physiological functions. Without direct measurement of these hormone levels, it is difficult to generate accurate and reliable data. The only phase in which hormonal status can be confidently inferred is menstruation, as this phase is defined by low concentrations of ovarian hormones. Understanding this relationship in elite female football players is crucial for optimizing training load, health management, recovery strategies, and injury prevention. The aim was to investigate the association between the early follicular phase (menstruation) and the incidence of musculoskeletal time-loss injuries in elite female football players across four competitive seasons. Menstrual cycle and injury data were prospectively collected from 33 elite female football players between the 2019/20 and 2022/23 seasons. Menstrual cycle was tracked using a calendar-based digital tool, and injuries were classified according to the OSICS-10 coding system. Injury incidence rates per 1,000 h of exposure were computed and compared between bleeding and non-bleeding phases. It should be noted that in this article, the terms bleeding, menstruation, phase 1, and early follicular phase are used interchangeably to refer to the same stage of the menstrual cycle. A total of 852 menstrual cycles were analysed, during which 80 injuries were recorded. Of these, 18 (22.5%) occurred during matches and 62 (77.5%) during training. The most common injury types were muscle injuries (57.5%), ligament injuries (30%), and tendon injuries (12.5%). Injuries during the bleeding phase accounted for 13.7% (n = 11) of all cases. The overall injury incidence rate was 6.42 per 1,000 h (95% CI: 5.09-7.99), with an incidence of 5.46 per 1,000 h during the bleeding phase and 6.60 per 1,000 h during non-bleeding phases (p = 0.55). Although injury incidence was not significantly different between phases, the injury burden was substantially higher during bleeding (684 vs. 206 days lost per 1,000 h; p = 0.0027), indicating that injuries sustained during menstruation resulted in more severe consequences. This study provides evidence that injury incidence is similar during menstrual bleeding compared to non-bleeding days in elite female football players. However, injuries occurring during menstruation are associated with a significantly higher burden, suggesting an increased risk of more severe injuries during this phase, these findings highlight the importance of individualized menstrual tracking for injury prevention and athlete health management. Further research with precise hormonal monitoring is needed to confirm these observations and to inform training, recovery, and health strategies in female athletes.

18 The adolescent football mind: how age and playing position influence competitive state anxiety, self-confidence, and cognitive interference in Indian footballers

Reference: Front Sports Act Living. 2025 Dec 16:7:1695658. doi: 10.3389/fspor.2025.1695658. eCollection 2025.
Authors: Debabrata Chatterjee, Santi Ranjan Dasgupta, Arkadeb Dutta
Download link: https://www.frontiersin.org/journals/sports-and-active-living/articles/10.3389/fspor.2025.1695658/full
Summary: Elevated competitive state anxiety, performance-interfering thoughts, and low self-confidence can impair coping ability to stress, and deteriorate athletic performance. Exaggerated competitive state anxiety is the manifestation of an athlete’s negative appraisal of their own performance and fear of failure. Very little is known about the susceptibility to these psychological factors in adolescent athletes at grassroots football. The present study aimed to examine differences in competitive state anxiety, self-confidence, and cognitive interference scores between mid- and late adolescent Indian players and those with different playing positions. The inter-relationship between the age, playing experience [PE], cognitive state anxiety [CA], somatic state anxiety [SA], cognitive interference [CI], and self-confidence [SC] was also examined. Out of the ninety-one young (age range: 14-20 years), male footballers recruited from an elite football academy through convenience sampling, eighty-three (age: 17.08 ± 1.56 years; positions: goalkeepers = 12, defenders = 17, midfielders = 44, strikers = 10) completed the study. The original Revised Competitive State Anxiety Inventory (CSAI-2R) questionnaire and the Thought Occurrence Questionnaire for Sport (TOQS) were self-administered during intramural competition in mid-adolescent (MA, n = 50) and late-adolescent (LA, n = 33) players. Non-parametric correlation, Mann-Whitney U, and Kruskal-Wallis statistical tests were conducted. Age was positively associated with PE (τ = +0.3, p < 0.001) and SC (τ = +0.16, p < 0.05); and negatively associated with CA (τ = -0.2, p < 0.05), SA (τ = -0.2, p < 0.05), thoughts of escape [ToE (τ = -0.19, p < 0.05)], situation-irrelevant thoughts [SIT (τ = -0.19, p < 0.05)], and performance worries [PW (τ = -0.15, p < 0.05)], CI (τ = -0.2, p < 0.001). The SA and CA were significantly higher in the MA than in LA (p < 0.01), as well as CI (p < 0.001). There was a significant effect of playing position only on CA scores (p < 0.05). post-hoc analysis found a significantly higher level of CA in strikers than the goalkeepers (p < 0.05) and midfielders (p < 0.05). PE did not show any significant association with these CSAI-2R and TOQS parameters. Mid- adolescent players exhibited significantly lower SC and elevated SA, CA, and CI. The lower susceptibility to SA, CA, and CI was associated with increasing age and not with the PE. Adolescence in athletes is a critical phase for physiological, cognitive, and psychological maturation. Our findings emphasized the need for personalized psychological support in building mental resilience from a young age to cope with competitive pressure.

19 The decade of China’s football reform: Evolutionary characteristics, performance evaluation, and reflections and insights

Reference: PLoS One. 2025 Dec 30;20(12):e0339264. doi: 10.1371/journal.pone.0339264. eCollection 2025.
Authors: Zheng Li, Peng Du, Wanjin Deng, Dawei He, Xinyi Dong, Qifei Xia
Download link: https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0339264
Summary: The year 2025 marks the tenth anniversary of the issuance of the General Plan of Chinese Football Reform and Development, and the deepening development of China’s football reform necessitates a robust policy framework for support. Quantitative research on policy texts enables an objective evaluation of the policy efficacy in China’s football reform. This study constructs a quantitative assessment and empirical analysis framework encompassing nine primary variables and 40 secondary variables by employing methods such as textual analysis, the Delphi method, content analysis, and the PMC index model. Combining the PMC index model with surface plots, it conducts a quantitative evaluation of ten representative national-level policy texts introduced by China. The results indicate that, the overall assessment of these ten policies is „good.“ Among them, two policies (P1 and P3) are classified as exemplary policies, four (P4, P6, P7, and P8) are rated as good policies, and the remaining four are categorized as moderate policies. This suggests that while the policy design is generally scientifically sound and effective, there remains room for improvement in increasing the number of exemplary policies. The research conclusions suggest that exemplary policies exhibit characteristics of both localized top-level design and a leading-by-example effect; good policies encounter practical issues of coordinated policy design with localized deficiencies; and moderate policies still display governance phenomena of specialized institutional outputs coupled with mutual constraints. Therefore, the national strategy for China’s future football reform is characterized by longevity and gradualism, and there remains a lag in the implementation and actualization of policies. It is imperative to adopt a process-oriented mindset to achieve a substantive transformation from the advantages of policy texts to governance efficacy.

20 Matrix Metalloproteinase Polymorphisms as Genetic Risk Factors for Anterior Cruciate Ligament Injuries in Football Players: A Case-Control Study

Reference: Genes (Basel). 2025 Dec 16;16(12):1505. doi: 10.3390/genes16121505.
Authors: Kinga Wiktoria Łosińska, Agata Rzeszutko-Bełzowska, Krzysztof Ficek, Myosotis Massidda, Giovanna Maria Ghiani, Paweł Cięszczyk, Alison Victoria September
Download link: https://pmc.ncbi.nlm.nih.gov/articles/PMC12733233/pdf/genes-16-01505.pdf
Summary: Injuries to the anterior cruciate ligament (ACL) frequently occur in physically active populations and often lead to long-term complications, such as osteoarthritis and recurrent injury. The ACL’s structural integrity depends on extracellular matrix (ECM) remodeling, regulated by matrix metalloproteinases (MMPs). This study examined the association between three polymorphisms-MMP1 rs1799750, MMP10 rs486055, and MMP12 rs2276109-and ACL injury outcomes, including injury frequency, strain, partial rupture, and complete rupture.  A total of 296 physically active, unrelated Caucasian males participated in this case-control study, including 160 with ACL injuries (classified as ACLF-ACL injury frequency, ACLS-strain, ACLRP-partial rupture, ACLRC-complete rupture, and ACL-general ACL injury) and 136 healthy controls (CON) with no previous ACL injuries. All injuries resulted from non-contact mechanisms.  The MMP1 rs1799750 polymorphism showed a protective effect against ACL injury compared to controls (OR = 0.42, 95% CI: 0.21-0.85, Padj = 0.014). Within the injury group, MMP10 rs486055 was significantly associated with partial ruptures, especially in heterozygous carriers (OR = 3.47, 95% CI: 1.64-7.33, p = 0.001). The MMP12 rs2276109 variant, under a dominant model, was linked to higher injury frequency (OR = 3.80, 95% CI: 1.69-8.54, p = 0.0009) but showed no association with injury severity.  The MMP1 rs1799750 polymorphism showed a protective effect against ACL injury, MMP10 rs486055 was associated with an increased risk of partial rupture, and MMP12 rs2276109 was linked to higher injury frequency. These findings highlight the complex genetic and biomechanical interactions underlying ACL injuries. The MMP1 rs1799750 polymorphism showed a protective effect (58% reduction in the odds compared to controls) against ACL injury, MMP10 rs486055 was associated with an increased risk (3.47 times higher odds) of partial rupture, and MMP12 rs2276109 was linked to 3.8 times higher odds of an injury. Identifying genetic risk factors may support personalized injury prevention and rehabilitation strategies, offering new opportunities to reduce long-term complications in athletes and active individuals.

21 Artificial Intelligence in Sub-Elite Youth Football Players: Predicting Recovery Through Machine Learning Integration of Physical, Technical, Tactical and Maturational Data

Reference: Healthcare (Basel). 2025 Dec 16;13(24):3301. doi: 10.3390/healthcare13243301.
Authors: Pedro Afonso, Pedro Forte, Luís Branquinho, Ricardo Ferraz, Nuno Domingues Garrido, José Eduardo Teixeira
Download link: https://pmc.ncbi.nlm.nih.gov/articles/PMC12732887/pdf/healthcare-13-03301.pdf
Summary: Monitoring training load and recovery is essential for performance optimization and injury prevention in youth football. However, predicting subjective recovery in preadolescent athletes remains challenging due to biological variability and the multidimensional nature of training responses. This exploratory study examined whether supervised machine learning (ML) models could predict Total Quality of Recovery (TQR) using integrated external load, internal load, anthropometric and maturational variables collected over one competitive microcycle.  Forty male sub-elite U11 and U13 football players (age 10.3 ± 0.7 years; height 1.43 ± 0.08 m; body mass 38.6 ± 6.2 kg; BMI 18.7 ± 2.1 kg/m2) completed a microcycle comprising four training sessions (MD-4 to MD-1) and one official match (MD). A total of 158 performance-related variables were extracted, including external load (GPS-derived metrics), internal load (RPE and sRPE), heart rate indicators (U13 only), anthropometric and maturational measures, and tactical-cognitive indices (FUT-SAT). After preprocessing and aggregation at the player level, five supervised ML algorithms-K-Nearest Neighbors (KNN), Support Vector Machine (SVM), Decision Tree (DT), Random Forest (RF), and Gradient Boosting (GB)-were trained using a 70/30 train-test split and 5-fold cross-validation to classify TQR into Low, Moderate, and High categories.  Tree-based models (DT, GB) demonstrated the highest predictive performance, whereas linear and distance-based approaches (SVM, KNN) showed lower discriminative ability. Anthropometric and maturational factors emerged as the most influential predictors of TQR, with external and internal load contributing modestly. Predictive accuracy was moderate, reflecting the developmental variability characteristics of this age group.  Using combined physiological, mechanical, and maturational data, these ML-based monitoring systems can simulate subjective recovery in young football players, offering potential as decision-support tools in youth sub-elite football and encouraging a more holistic and individualized approach to training and recovery management.

22 Integrated Anthropometric, Physiological and Biological Assessment of Elite Youth Football Players Using Machine Learning

Reference: Diagnostics (Basel). 2025 Dec 18;15(24):3238. doi: 10.3390/diagnostics15243238.
Authors: Luiza Camelia Nechita, Tudor Vladimir Gurau, Carmina Liana Musat, Ancuța Elena Țupu, Gabriela Gurau, Doina Carina Voinescu, Aurel Nechita
Download link: https://pmc.ncbi.nlm.nih.gov/articles/PMC12731802/pdf/diagnostics-15-03238.pdf
Summary: Youth football players experience rapid physical and biological changes while being exposed to high training loads, increasing performance demands and musculoskeletal injury risk. Current evaluations often analyze anthropometric, physiological, and biological domains separately, and few studies integrate these dimensions using machine-learning (ML) approaches. The aim was to provide a multidimensional assessment of elite youth football players and investigate how anthropometric, physical, and biological markers jointly relate to performance through classical statistics and ML.  One hundred elite players (14-18 years) underwent standardized anthropometric, physical, and laboratory assessments. Analyses included descriptive statistics, ANOVA/MANOVA, PCA, factor analysis, composite biological indices, and ML models (linear regression, SVR) with 5-fold cross-validation. K-means clustering explored hidden adaptation phenotypes.  Older players showed higher weight and BMI, physical testing revealed consistent limb asymmetry (~5%), and biological markers remained within reference ranges. PCA and factor analysis extracted latent structural and metabolic domains. Linear regression predicted performance with R2 ≈ 0.59, while SVR underperformed. K-means identified three adaptation phenotypes. : Performance and resilience arise from interactions between structural, functional, and biological domains. Interpretable ML methods enhance individualized monitoring, early risk detection, and evidence-based injury-prevention strategies.

23 Football clubs and their ‚hive mind‘: distributed situation awareness (DSA) and its role in injury management

Reference: Br J Sports Med. 2025 Dec 29;59(23):1641-1642. doi: 10.1136/bjsports-2025-111249.
Authors: Scott Mclean, Paul M Salmon, Mitch Naughton, Tom Page, Barry Drust, Michael Brownlow
Download link: https://bjsm.bmj.com/content/bjsports/59/23/1641.full.pdf

24 Hip adduction and abduction isometric force production in young football players: reliability of different testing protocols

Reference: Sci Rep. 2025 Dec 28. doi: 10.1038/s41598-025-33461-1. Online ahead of print.
Authors: Vincenzo Rago, José M Oliva-Lozano, Rick Cost, Javier Arnaiz-Lastras, Fábio Yuzo Nakamura, Pedro Figueiredo
Download link: https://www.nature.com/articles/s41598-025-33461-1_reference.pdf