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 Effect of the FIFA 11+ Warm-Up Program on Knee Instability and Motor Performance in Male Youth Soccer Players

Reference: Sensors (Basel). 2025 Apr 11;25(8):2425. doi: 10.3390/s25082425.
Authors: Badis Soussi, Tamás Horváth, Zsombor Lacza, Mira Ambrus
Download link: https://www.mdpi.com/1424-8220/25/8/2425
Summary: This study aimed to investigate the effect of the FIFA 11+ program on knee instability and motor performance in male youth soccer players. Thirty male youth soccer players were divided into two groups: the experimental group (FIFA+) performed the FIFA 11+ program for 10 weeks, while the control group followed their usual warm-up routine. Dynamic knee valgus (DKV) and squat depth were assessed using a Microsoft Azure Kinect camera and dynaknee software. Maximal isometric muscle force was measured with a dynamometer. The Y Balance test was used to evaluate dynamic balance, while a countermovement jump test assessed lower limb power. The knee range of motion was measured with a goniometer, and the t-test was used to evaluate agility. After the intervention, the FIFA+ group showed a significant decrease in DKV and squat depth (p < 0.05), while the control group showed no significant changes (p > 0.05). Both groups improved in motor performance, with slight progress noted in the FIFA+ group. However, neither group demonstrated significant improvement in dynamic balance (p > 0.05). While the FIFA 11+ program may not substantially enhance overall motor performance or match the effectiveness of other training regimens, it shows potential for addressing biomechanical deficiencies and reducing the risk of injuries, particularly those related to dynamic knee valgus.

2 The Influence of Weekly Training Load on Match Physical Demands in Spanish Professional Soccer Players: A Full In-Season Study

Reference: Sensors (Basel). 2025 Apr 11;25(8):2413. doi: 10.3390/s25082413.
Authors: José C Ponce-Bordón, Jorge Polo-Tejada, David Lobo-Triviño, Borja Sanabria-Pino, Javier Raya-González, Alberto Muñoz, Tomás García-Calvo
Download link: https://www.mdpi.com/1424-8220/25/8/2413
Summary: This study aimed (i) to analyze the relationship between weekly accumulated training load (TL) and match physical demands in the same week and (ii) to describe the training/match ratios of different external load measures considering variations across different training days. Twenty-one Spanish male professional soccer players were involved in the study. Total distance (TD), medium speed running (MSR, distance 10.8-18.0 km·h-1), high-speed running (HSR, >21 km·h-1), very high-speed running (VHSR, 18.0-25.2 km·h-1), sprinting-speed running distance (Sprint, >25.2 km·h-1), player load (PL), number of accelerations (ACC), and decelerations (DEC) were recorded during training sessions and matches using 10 Hz GPS devices. Correlations between the weekly TL and match physical demands were trivial and negative for TD (r = -0.08) and PL (r = -0.05); trivial and positive for MSR (r = 0.02), HSR (r = 0.07), Sprint (r = 0.09), and DEC (r = 0.06); and small and positive for VHSR (r = 0.22) and ACC (r = 0.19). The greatest TD, MSR, VHSR, Sprint, HSR, and PL values and their derivate ratios occurred in MD-3. The present study highlights the need for soccer athletes to be exposed to similar demands to those observed during matches.

3 Predictors of Chronic Ankle Instability Among Soccer Players

Reference: Medicina (Kaunas). 2025 Mar 21;61(4):555. doi: 10.3390/medicina61040555.
Author: Ahmad Alanazi
Download link: https://www.mdpi.com/1648-9144/61/4/555
Summary: Chronic ankle instability (CAI) is prevalent among soccer players, often resulting from recurrent ankle injuries (RAIs). Despite its impact on performance and long-term joint health, the associated risk factors remain insufficiently explored. This study aimed to identify the key risk factors for CAI among soccer players. A cross-sectional study was conducted among 310 soccer players from different professional sports clubs. The Arabic version of the Cumberland Ankle Instability Tool (Ar-CAIT) was used to assess ankle instability. Spearman’s rho correlation and multiple linear regression were used to identify significant predictors of CAI. Additionally, structural equation modeling (SEM) was used to conduct mediation analysis and evaluate potential indirect effects. Spearman’s correlation analysis revealed significant negative associations between Ar-CAIT scores and both BMI (r = -0.158, p < 0.05) and RAI (r = -0.273, p < 0.01), while training hours were positively correlated with Ar-CAIT scores (r = 0.169, p < 0.05). Multiple regression analysis confirmed that higher BMI (β = -0.133, p = 0.017) and a greater number of ankle injuries (β = -0.285, p < 0.001) were associated with lower Ar-CAIT scores, whereas increased training hours (β = 0.140, p = 0.010) were predictive of better ankle stability. Mediation analysis revealed that BMI and training hours partially mediate the relationship between RAI and Ar-CAIT scores. RAI, elevated BMI, and reduced training hours were significant predictors of CAI in soccer players. These findings emphasize the importance of implementing targeted injury prevention and rehabilitation strategies, particularly focusing on weight management and structured training programs to reduce CAI risk. Future longitudinal studies are required to explore the underlying mechanisms contributing to CAI development.

4 Physical and Physiological Demands of Official Beach Soccer Match-Play in Relation to Environmental Temperature

Reference: Sports (Basel). 2025 Apr 14;13(4):118. doi: 10.3390/sports13040118.
Authors: Thiago Carvalho, Vincenzo Rago, João Brito, Priscyla Praxedes, Marco Abreu, Davi Silva, Sara Pereira, Magni Mohr, Ivan Baptista, José Afonso
Download link: https://pmc.ncbi.nlm.nih.gov/articles/PMC12031097/pdf/sports-13-00118.pdf
Summary: Environmental temperature (Te) is a main atmospheric parameter that may affect the physical and physiological demands of outdoor sports. Thus, this study aimed to examine the relationship of Te with the physical and physiological demands of beach soccer match-play. Physical and physiological demands were collected from 60 male players during Portuguese elite beach soccer championship matches using a 10 Hz wearable global positioning system, heart rate, and the rate of perceived exertion (RPE). A bilateral counter-movement jump (CMJ) test assessed lower limb power performance before and immediately after the match. Fluid loss was determined by body mass weighing before and after the end of the match. Te and wet-bulb globe temperature (WBGT) parameters were continuously recorded. The matches occurred across Te ranging from ~20.0 °C to 43.0 °C. Physical demands, CMJ height, peak heart rate (HRpeak), mean heart rate (HRmean), and RPE were not correlated with Te. However, a significant correlation was found between fluid loss and Te (r [95% CIs] = 0.67 [0.43-0.75]; p < 0.001). Beach soccer players maintained physical performance independent of Te. The specific characteristics of the sport may have promoted adequate thermoregulatory adaptations, helping maintain the players‘ physical performance, particularly in matches played under high Te conditions. Elite beach soccer players maintained their physical performance independently of Te and despite experiencing dehydration (a body mass decrease of more than 2%) when the Te exceeded 35 °C.

5 Caffeine Effects on Physical Performance and Sport-Specific Skills in Elite Youth Soccer Players: A Randomised Trial Using the Balanced Placebo Design

Reference: Sports (Basel). 2025 Mar 31;13(4):106. doi: 10.3390/sports13040106.
Authors: Eduard Bezuglov, Timur Vakhidov, Ryland Morgans, Georgiy Malyakin, Anton Emanov, Egana Koroleva, Elizaveta Kapralova, Oleg Talibov
Download link: https://pmc.ncbi.nlm.nih.gov/articles/PMC12031558/pdf/sports-13-00106.pdf
Summary: The aim of the study was to examine the safety and effects of relatively high caffeine doses on physical performance and sport-specific skills of young elite soccer players. Fifty-four soccer players from an elite Russian soccer academy participated in the blinded randomised placebo-controlled study with a double-blinded and balanced design. Participants were divided into four groups: group 1 CAF/CAF; group 2 CAF/PLA group 3 PLA/PLA and group 4 PLA/CAF. All participants were administered 400 mg of caffeine or the placebo. The data demonstrated that a single 400 mg caffeine administration 60 min before exercise had a positive effect on repeated sprint ability (RSA) test parameters such as fatigue index (for both groups p < 0.001) and percentage decrement score (for both groups p < 0.001). In group 4, statistically significant improvements were also found when performing the fourth and sixth sprint during the RSA test (p = 0.039 and p = 0.005, respectively). Group 1 also showed a statistically significant improvement in dribbling speed performance (p = 0.048). It was demonstrated that the number of adverse events in all four groups was not different (p = 0.56). A single administration of 400 mg of caffeine 60 min prior to maximal intensity physical activity can be considered reasonable and safe for young elite soccer players.

6 Risk Factors of Ankle Sprain in Soccer Players: A Systematic Review and Meta-Analysis

Reference: Sports (Basel). 2025 Mar 28;13(4):105. doi: 10.3390/sports13040105.
Authors: Amir Human Hoveidaei, Amir Reza Moradi, Amin Nakhostin-Ansari, Mohammad Mehdi Mousavi Nasab, Seyed Pouya Taghavi, Shayan Eghdami, Bijan Forogh, Masumeh Bagherzadeh Cham, Christopher J Murdock
Download link: https://pmc.ncbi.nlm.nih.gov/articles/PMC12031617/pdf/sports-13-00105.pdf
Summary: Soccer is associated with substantial injury risk, with reported between 13 to 35 injuries per 1000 player-hours of competitive play. Notably, approximately 77% of soccer-related ankle injuries are attributed to ankle sprain injuries (ASIs). ASI can lead to chronic ankle instability, obesity, and post-traumatic osteoarthritis. This study focuses on identifying factors such as gender, age, body mass index (BMI), and a history of ASIs, which contribute to the development of ASI in soccer players. A systematic literature search was conducted in October 2023 across databases, including PubMed, Web of Science, Scopus, Cochrane Library, and ProQuest, without applying any filters. Keywords included ankle, ankle joint, sprain, risk factors, etc. Data extraction was performed on the included studies, with findings standardized and analyzed using Stata Statistical Software: Release 17 to determine a weighted treatment effect. Our systematic review included 26 studies. The meta-analysis revealed that a history of ankle sprain is the most significant risk factor for future ASIs. BMI emerged as a risk factor in three out of seven studies, while age and height were significant in one out of six studies each. Gender and weight were not found to significantly affect ASI occurrence. Other factors identified but not subjected to a meta-analysis due to methodological heterogeneity or insufficient studies included playing surface, joint laxity, muscle weakness, match congestion, strength asymmetries, ground reaction forces, balance maintenance, skill level, and playing position. This research contributes valuable insights into the prevention of ASIs in soccer, highlighting the importance of previous ankle sprains and playing surface quality. These findings assist sports professionals in developing optimal conditions and strategies for effective ankle sprain prevention.

7 Autonomic Nervous System Control in Male and Female Elite Soccer Players: Importance of Different Training Routines and Perceived Stress

Reference: J Cardiovasc Dev Dis. 2025 Apr 10;12(4):150. doi: 10.3390/jcdd12040150.
Authors: Gianluigi Oggionni, Eleonora Pagani, Jacopo Rizzardini, Margherita Rigillo, Luca Giovanelli, Mara Malacarne, Nuno Loureiro, Júlia Machado Ribeiro, Piero Volpi, Massimo Pagani, Daniela Lucini
Download link: https://pmc.ncbi.nlm.nih.gov/articles/PMC12028154/pdf/jcdd-12-00150.pdf
Summary: The assessment of cardiac autonomic regulation (CAR) with non-invasive techniques, such as heart rate variability (HRV), might be of practical interest in elite sports, considering its importance in determining training. We studied 117 soccer players (74 male and 43 female) from three First Division European soccer teams. We used a ranked Autonomic Nervous System Index (ANSI, resulting from the combination of multivariate statistical methodologies applied to HRV-derived indices) to assess CAR. We hypothesized that ANSI might differentiate playing positions, considering goalkeepers, defenders, midfielders, and forwards. We also assessed the perception of somatic symptoms and stress. We observed in male athletes that ANSI was significantly greater in males as compared to females (p < 0.001), being higher in midfielders and defenders (p = 0.035), who usually sustain the greatest external load. Interestingly, this result was not observed in female athletes, who, instead, reported a significantly higher perception of somatic symptoms (p = 0.018) and stress (p = 0.049), the latter being particularly high in midfielders and forwards (p = 0.045). This approach might represent a convenient model to study the effects of long-term physical exercise on CAR in soccer, even to unveil possible differences due to sex, different playing positions characterized by distinct exercise routines, or stress perception.

8 Effects of pre-exercise snack bars with low- and high-glycemic index on soccer-specific performance: An application of continuous glucose monitoring

Reference: J Sports Sci. 2025 Apr 24:1-9. doi: 10.1080/02640414.2025.2497672. Online ahead of print.
Authors: Yuxin Zuo, Eric Tsz-Chun Poon, Xiaoyuan Zhang, Borui Zhang, Chen Zheng, Fenghua Sun
Summary: This study aimed to investigate the effects of pre-exercise snack bars with different glycemic indices (GI) on soccer-specific performance. In a randomised crossover study design, 12 recreational soccer players consumed either low- or high-GI snack bars 1 h before 25 min small-sided game (SSG) training. Following the SSG training, the players‘ passing abilities were assessed using the Loughborough Soccer Passing Test (LSPT), followed by aerobic endurance capacities YOYO Intermittent Recovery Test Level 1 (YYIRT), respectively. Continuous glucose monitors (CGM) were used to track the glycemic response during SSG training and all tests. The result showed that participants‘ performance was significantly better in the low-GI trial compared with the high-GI trial for the LSPT movement (58.27 ± 10.99 vs. 62.27 ± 7.63 s, p < 0.05), LSPT total (74.64 ± 22.66 vs. 83.18 ± 18.29 s, p < 0.05), and YYIRT (1196 ± 657 vs. 993 ± 536 m, p < 0.01). The CGM data indicated a lower mean (6.2 ± 0.7 vs. 7.1 ± 0.6 mmol/L, p < 0.01) and lower glycemic variability in postprandial interstitial glucose levels in the low-GI trial, compared with the high-GI trial. In conclusion, pre-exercise low-GI snacks could result in more stable glycemic responses and enhance soccer-specific performance.

9 What Factors Influence Head Acceleration During a Purposeful Header in Soccer Players? A Systematic Review

Reference: Sports Med. 2025 Apr 24. doi: 10.1007/s40279-025-02209-2. Online ahead of print.
Authors: Rebecca Blyth, Gerard Farrell, Anja Zoellner, Osman Hassan Ahmed, Melanie Bussey, Olivia Galea, Gisela Sole
Download link: https://link.springer.com/content/pdf/10.1007/s40279-025-02209-2.pdf
Summary: Head acceleration is often used as a proxy measurement for concussion risk. It is unclear what factors contribute to head acceleration during a purposeful header. The objective of this systematic is to identify what factors influence head acceleration during a header and highlight areas that have not been explored. Studies were included if they assessed the effect of an independent variable on head acceleration during a purposeful header. There were no exclusion criteria relating to age, sex, playing level, study design, or publication date. Databases included Scopus, Web of Science, MEDLINE, EMBASE, CINAHL, SPORTDiscus and ClinicalKey, and grey literature was also searched. Searches were re-run in January 2024. Each included study underwent a risk of bias or quality assessment, using several tools owing to varied study designs (ROBINS-I, RoB2, modified Downs and Black and AXIS). Results are presented in tabular form, categorised by independent variable(s) and accompanied by a narrative results section. A total of 60 studies were included. Study designs included one-off measurements with variable(s), cohort, cross-sectional and randomised controlled trials (RCTs). Influencing factors included ball velocity and characteristics, header type, impact location, neck training interventions, fatigue protocols, neck strength, demographics, playing scenario and personal protective equipment. A wide range of heading trials and methods of measuring head acceleration were used. Results were conflicting for several variables. There was some consistent evidence that increased ball speed/mass/inflation increased head acceleration. Female players sustained greater head accelerations than males, and some evidence suggested that increased neck strength reduced head acceleration, but not in all cases. This review confirmed traditional neck strengthening is not effective in reducing head acceleration; however, adding neuromuscular exercises appeared to be effective. There was a lack of evidence investigating other systems that may affect head acceleration such as vestibular function, oculomotor performance, rate of force development and cervical spine proprioception. This review highlights the range of studies investigating head acceleration during a purposeful header. Included studies were of varying quality, and one limitation was the lack of transformation of the acceleration measures to a consistent frame of reference. Implications from this study suggest potential measures that may reduce head acceleration and therefore improve the safety of performing a purposeful header. These include reducing ball inflation pressure, limiting headers from long range/high speed balls (especially in children/adolescents and females) and ensuring neuromuscular exercises are incorporated into neck training programmes. Dynamic muscle strength outcomes, including measures such as rate of force development, are challenging to measure but should be considered an essential component of neck training when the aim is to reduce head acceleration in a ballistic task such as a header.

10 Effect of Six Weeks‘ Isometric Strength Training Compared to Traditional Strength Training on Gains in Strength, Power, and Speed in Male Academy Soccer Players

Reference: Res Q Exerc Sport. 2025 Apr 24:1-8. doi: 10.1080/02701367.2025.2488843. Online ahead of print.
Authors: Luke S Bailey, Joe Phillips, George Farrell, Stephen J McQuilliam, Robert M Erskine
Summary: Elevated sport-specific physical demands and congested fixture schedules leave little recovery time and augment fatigue levels in soccer players. Compared to traditional strength training (TST), isometric strength training (IST) may elicit comparative improvements in strength and performance-related parameters in soccer players, while reducing fatigue during periods of elevated competitive loading. This study compared the effects of 6-weeks‘ IST and TST on gains in strength, power, and speed in male academy soccer players. Eighteen athletes from a Football Association League 2 club’s academy (age: 17.2 ± 0.6 years, height: 1.79 ± 0.06 m, body mass: 71.6 ± 3.4 kg) were randomly assigned to either the IST (n = 9) or TST (n = 9) group. Baseline and post-training testing included trap bar squat one-repetition maximum (1-RM), isometric mid-thigh pull (IMTP), bilateral vertical countermovement jump (CMJ), and 10 m and 40 m linear sprints. Each group completed 12 training intervention sessions over six weeks, which comprised either an isometric or dynamic variation of a mid-thigh (clean) pull, split squat, and hip thrust. Results indicated no group × time interaction effect on trap bar squat 1-RM (p = .171, ηp2 = 0.107), IMTP peak force (p = .478, ηp2 = 0.039), CMJ jump height (JH; p = .463, ηp2 = 0.028), CMJ peak power (PP; p = .868, ηp2 = 0.001), 10 m acceleration (p = .074, ηp2 = 0.186), or sprint velocity (p = .348, ηp2 = 0.058). However, there were main effects of time on trap bar squat 1-RM (p < .001, ηp2 = 0.634), CMJ JH (p = .031, ηp2 = 0.255) and sprint velocity (p = .012, ηp2 = 0.324). In conclusion, IST is just as effective as TST in improving (or maintaining) strength, power, and speed during fixture-congested schedules in men’s academy soccer.

11 Changes in Single Leg Countermovement Jump Force-Time Characteristics Pre, Post and 2 Days Postmatch in Elite Girls‘ Youth Soccer

Reference: J Strength Cond Res. 2025 Apr 23. doi: 10.1519/JSC.0000000000005078. Online ahead of print.
Authors: Jack T Fahey, Paul Comfort, Nicholas J Ripley
Summary: This study was designed to assess changes in force-time characteristics during the single leg countermovement jump pre- (n = 122), immediately postmatch (n = 121), and 2 days postmatch (MD +2, n = 105) in elite girls‘ soccer players (n = 32, 13.9 ± 1.1 years, 163.4 ± 5.2 cm, 53.6 ± 8.2 kg), after 8 competitive matches, using force plates. Significant main effects were found for all variables (p < 0.05). Trivial to small, yet significant increases in jump height (JH) and relative mean braking and propulsive forces were observed postmatch for both limbs. Trivial to small, yet significant increases in JH and jump momentum were observed MD +2 for both limbs. Trivial to small, yet significant increases were observed for body mass and time to take-off were observed MD +2 compared with postmatch for both limbs. Playing time was not associated with percentage change in force-time characteristics (r ≤ 0.20). Competitive matches in elite girls‘ soccer seem to provide an insufficient stimulus to acute fatigue. Force-time characteristics were improved at postmatch and MD +2 when compared with prematch. This provides useful information for sports coaches and strength and conditioning coaches when prescribing training for progressive overload. Because girls‘ soccer players experience increased demands with age and competition levels, strength and conditioning coaches should consider the removal of second-day recovery sessions and include strength and high-intensity training on MD +2 to better prepare players to cope with the increasing demands and to reduce injury risk, which remains substantially higher than that for boys.

12 Effects of a Sleep Hygiene Intervention Period on the Internal and External, Inter- and Intra-match Demands of Male University-Level Soccer Players During a Tournament

Reference: J Strength Cond Res. 2025 Apr 23. doi: 10.1519/JSC.0000000000005083. Online ahead of print.
Authors: Michael Prevoo, Adéle Broodryk, Mark Kramer
Summary: Soccer is a physiologically and psychologically demanding sport, requiring players to optimize their sleep to enhance their recovery and ensure optimal performance during a match. Therefore, this study aimed to determine the effect of a sleep hygiene intervention period (SHP) on the internal and external match demands during an 8-match tournament. Sixteen male university-level soccer players‘ (average age: 22.2 ± 3 years; stature: 167.6 ± 6.4 cm; mass: 62 ± 6.6 kg) movement patterns, heart rate, RPE, and sleep quality (Pittsburgh Sleep Quality Index-PSQI) were compared over an intervention period consisting of 2 matches (no-sleep hygiene period: no-SHP), 4 matches (sleep-hygiene period-SHP, adhering to 10 SHP principles over 4 weeks), and again 2 matches of no-SHP. A significantly improved global PSQI score (p = 0.03), sleep latency (p = 0.05), and sleep hours (p = 0.004) were seen following the SHP. Comparing the match halves of the no-SHP and SHP, significant differences were found for total distance (p < 0.001), distances completed while jogging (p < 0.001), running (p < 0.001), and sprinting (p = 0.03), as well as distances covered in the medium (p = 0.05) and high-velocity (p < 0.001) zones, and low (p < 0.001) and medium (p < 0.001) decelerative zones and for all accelerative zones (p < 0.001). Participants were able to surpass their work rates after the SHP with no RPE increases observed, hence demonstrating the usefulness of putting organized sleep into practice. Therefore, it is recommended that players and coaching staff implement sleep hygiene guidelines more regularly, as it may result in noteworthy performance improvements.

13 Fueling Soccer Players: A Scoping Review and Audit of Literature Related to Soccer-Specific Guidelines for Carbohydrate Intake

Reference: Sports Med. 2025 Apr 22. doi: 10.1007/s40279-025-02224-3. Online ahead of print.
Authors: Wee Lun Foo, Emma Tester, Graeme L Close, José L Areta, James P Morton
Download link: https://link.springer.com/content/pdf/10.1007/s40279-025-02224-3.pdf
Summary: Professional soccer players are advised to consume 3-8 g kg-1 body mass day-1 of carbohydrate (CHO) on the basis of training demands, fixture schedule and personal objectives. However, owing to the lack of randomized controlled trials on elite players, these guidelines largely rely on data interpretation and practitioner experience. To identify the gaps in existing literature that inform CHO guidelines for soccer players. A scoping review was conducted without date restrictions up to 21 March 2024, employing a three-step search strategy to identify relevant English-language primary and secondary articles through PubMed and reference searching. Data were extracted using a standardized audit tool from studies assessing direct and indirect impacts of CHO on soccer players‘ performance and health. Within 258 studies identified, experimental studies were the most common (~ 36%), followed by observational (~ 33%) and narrative reviews (~ 26%), with systematic reviews, meta-analyses and case studies making up the rest (~ 5%). Most observational studies were field-based (~ 98%), while experimental studies were laboratory-based (~ 75%). Among 4475 participants, ~ 16% were female, and only ~ 12% of the original research was exclusively conducted on female players. Observational studies included developmental (~ 52%) and professional players (~ 31%), whereas experimental studies primarily featured recreationally active (~ 40%) and collegiate/university participants (~ 26%). Key research topics were ‚dietary intake‘ (~ 52%) and „energy expenditure and dietary intake“ (~ 30%) for observational studies and ‚CHO interventions‘ (~ 74%) for experimental studies. Only eight experimental studies exclusively involved professional players, focusing on CHO intervention (n = 7) and CHO co-ingestion (n = 1). Narrative reviews were published in journals with higher impact factor (4.1 ± 6.4) than were observational studies (3.2 ± 1.6, p < 0.001) and experimental studies (3.4 ± 1.6, p < 0.001). Narrative reviews had the most studies, with Altmetric scores ≥ 20 (n = 26), followed by experimental (n = 16) and observational studies (n = 14). Current CHO guidelines for elite soccer players lack experimental research specific to professional and world-class players. More field-based experimental trials involving elite soccer players are required to ensure evidence-based CHO recommendations.

14 Prevalence of Vitamin D Deficiency Among Young Elite Soccer Players Living Above 55 Degrees North Latitude and Evaluation of the Effectiveness of Self-Used Preventive Methods

Reference: Transl Sports Med. 2025 Apr 11:2025:2299710. doi: 10.1155/tsm2/2299710. eCollection 2025.
Authors: Bezuglov Eduard, Achkasov Evgeniy, Vinogradov Mikhail, Baranova Daria, Shurygin Vladimir, Rudiakova Elizaveta, Usmanova Elvira, Vakhidov Timur, Malyakin Georgiy, Ilsiuiar Anishchenko, Kapralova Elizaveta
Download link: https://pmc.ncbi.nlm.nih.gov/articles/PMC12008557/pdf/TSMED2025-2299710.pdf
Summary: The widespread prevalence of vitamin D deficiency among young elite soccer players living above 40° north latitude is a significant issue. Considering the adverse effects of vitamin D deficiency, it is crucial to investigate its prevalence and the effectiveness of self-used preventive strategies among high-risk groups. This study involved 209 young athletes (aged 7-18 years, mean age: 12.79 ± 3.04 years, weight: 50.11 ± 17.75 kg, height: 1.60 ± 0.19 m, and BMI: 18.69 ± 2.75) from a leading soccer academy, residing above 55° north latitude. Blood samples were collected in winter to analyze the total 25-hydroxyvitamin D (25(OH)D) levels using liquid chromatography-mass spectrometry. High prevalence of insufficiency (38.3%) and deficiency (26.8%) of 25(OH)D was identified. There were no significant differences in the severity of deficiency among different age groups (6-9 years, 10-14 years, and 15-18 years) or during growth spurts. The analysis of self-used preventive methods showed no significant differences between the compared groups (p=0.149). Vitamin D deficiency and insufficiency are widespread among young elite soccer players living above 55° north latitude and training indoors. The effectiveness of self-used preventive methods is considered low.

15 Post-Match Recovery Responses in Italian Serie A Youth Soccer Players: Effects of Manipulating Training Load 48 h After Match Play

Reference: Eur J Sport Sci. 2025 May;25(5):e12297. doi: 10.1002/ejsc.12297.
Authors: Alberto Franceschi, Mark A Robinson, Daniel J Owens, Thomas Brownlee, Darragh R Connolly, Aaron J Coutts, Duccio Ferrari Bravo, Kevin Enright
Download link: https://pmc.ncbi.nlm.nih.gov/articles/PMC12010046/pdf/EJSC-25-e12297.pdf
Summary: This study described the recovery responses following match play and examined the effects of manipulating training load 48 h post-match in Italian Serie A youth soccer players. Forty-eight players were assessed using the countermovement jump (CMJ), isometric posterior-chain muscle test (IPC), muscle soreness and fatigue before (pre) and after (0.5 h post, 48 h post and 72 h post) a match. At 48 h post-match, players were randomly assigned to a complete training (CT; n = 26) or a reduced training (RT; n = 22) group. Recovery differences were analysed between time points and training groups, with training loads quantified on match day (MD) and match day plus two (MD + 2). Recovery measures were impaired immediately post-match (p < 0.05). IPC and muscle soreness demonstrated incomplete recovery 48 h post-match (p < 0.05), whereas CMJ and fatigue returned to baseline (p > 0.05). Training load on MD did not differ between groups (p > 0.05), whereas the CT group had higher load on MD + 2 compared to RT (p < 0.05). A significant time × group interaction was observed for CMJ height and IPC measures (p < 0.05), with reductions in physical performance observed in the CT group from 48 to 72 h post-match (p < 0.05). A youth soccer match acutely impaired physical performance and recovery status, with prolonged and incomplete recovery of hamstring force and elevated muscle soreness 48 h post-match. A high-volume and high-intensity session administered 48 h post-match negatively influenced physical performance compared to a moderate training session.

16 High risk of new knee injuries, lower activity level and reduced knee function: A controlled follow-up of male football (soccer) players 6-9 years after primary anterior cruciate ligament reconstruction

Reference: J Sci Med Sport. 2025 Apr 4:S1440-2440(25)00097-0. doi: 10.1016/j.jsams.2025.03.016. Online ahead of print.
Authors: Anne Fältström, Joanna Kvist, Martin Hägglund
Download link: https://www.jsams.org/action/showPdf?pii=S1440-2440%2825%2900097-0
Summary: The aim was to study the risk of new knee injuries and patient-reported outcomes in male football players at any playing level 6-9 years after primary anterior cruciate ligament reconstruction (ACLR) versus knee-healthy controls. Football players (n = 384) who underwent an ACLR between 1 and 3 years previously and knee-healthy controls (n = 110) were surveyed regarding football playing status, activity level (Tegner Activity Scale), knee function (0-10 scale), satisfaction with current activity level (1-10), satisfaction with knee function (1-7), and new knee injuries. Ninety-three players with ACLR and 63 knee-healthy controls were included and followed for mean 5.4 years (6-9 years after primary ACLR for players with ACLR). Thirty-four players with ACLR (37 %) had sustained a new ACL injury (re-rupture or contralateral rupture) versus 5 (8 %) controls. Players with ACLR had almost 5-fold higher risk of new ACL injury than controls (risk ratio, 4.61; 95 % confidence interval, 1.91-11.13; p < 0.001). Compared with controls, players with ACLR played football to a lower extent (27 % vs 65 %, p < 0.001) had a lower activity level (Tegner: median [interquartile range], 4 [6] vs 9 [5], p < 0.001), knee function (median, 8 [3] vs 9 [2], p < 0.001), and satisfaction with activity level (median, 7 [3] vs 8 [3], p = 0.014) and knee function (median, 2 [2] vs 1 [1], p < 0.001). One-third of male football players with ACLR sustained a new ACL injury within 6-9 years, with an almost 5-fold higher risk than controls. Players with ACLR had lower activity level and knee function and were less satisfied with knee function and activity level.

17 Comparative outcomes of hip arthroscopy for femoroacetabular impingement in football and non-football athletes: a clinical analysis

Reference: Arch Orthop Trauma Surg. 2025 Apr 25;145(1):268. doi: 10.1007/s00402-025-05866-0.
Authors: Giancarlo Riccobono, Alfred Ferré-Anoirte, Roberto Seijas, David Barastegui, Ramon Cugat
Downlaod link: https://link.springer.com/content/pdf/10.1007/s00402-025-05866-0.pdf
Summary: Femoroacetabular impingement (FAI) is a common cause of hip pain and dysfunction, particularly among athletes, including football players. The condition is characterized by abnormal contact between the femoral head-neck junction and the acetabulum, leading to cartilage damage and labral tears. Hip arthroscopy has emerged as a minimally invasive treatment option, offering faster recovery and improved outcomes compared to traditional surgery. This study aims to compare outcomes between football players and non-football athletes undergoing hip arthroscopy for FAI. This retrospective, single-center study analyzed a database of patients undergoing hip arthroscopy for FAI between 2007 and 2023. The study compared football players (n = 16) and non-football athletes (n = 16), matched for age, sex, and BMI. Pre-operative assessment included the Hip Outcome Score (HOS), Visual Analog Scale (VAS), and other functional questionnaires. Radiographic evaluations included the alpha and Wiberg angles, and intra-operative findings were recorded. The surgical approach involved femoral and acetabular osteoplasty, labral repair, or labrectomy, depending on injury morphology. Both groups showed similar pre-operative pain levels (VAS) and functional scores. However, significant differences were observed in the Tegner and Hip Sports Activity Scores (HSAS), with football players showing higher activity levels pre-operatively. Both groups demonstrated significant improvements in alpha and Wiberg angles post-surgery (p < 0.001). The surgery duration was similar between groups, and no significant differences in post-operative outcomes were found between football and non-football players. Hip arthroscopy is effective for both football and non-football players with FAI, with both groups experiencing significant improvements in hip joint function and pain relief. While pre-operative functional scores differed, particularly in activity levels, both groups benefited from similar post-operative outcomes, suggesting that the surgical approach is suitable for active individuals across different sports. Further research is needed to explore long-term outcomes and return-to-sport rates in these populations.

18 Physical Responses During Matches of International Female Football Players with Cerebral Palsy According to Their Sport Classes

Reference: Sports (Basel). 2025 Mar 24;13(4):94. doi: 10.3390/sports13040094.
Authors: Oier Berasategui, Javier Yanci, Raúl Reina, Matías Henríquez, Aitor Iturricastillo, Ibai Errekagorri, Daniel Castillo
Download link: https://pmc.ncbi.nlm.nih.gov/articles/PMC12031368/pdf/sports-13-00094.pdf
Summary: International-level competition opportunities have recently been introduced for female footballers with cerebral palsy (CP), highlighting a gap in the research on their physical performance during matches. The objectives of this study were (I) to describe the physical responses during the 2022 Women’s World Cup of football players with cerebral palsy (CP) and (II) to analyze the differences in physical responses based on the players‘ sport class (i.e., FT1, FT2, and FT3). Physical responses were recorded using global positioning devices (GPS) during four official international matches. The results showed that FT2 players covered more explosive distances than FT1 players (p < 0.05; ES = -0.82), and FT2 and FT3 players achieved higher maximum velocities than FT1 players (p < 0.01; ES = -1.16 and p < 0.05; ES = -1.41, respectively). Furthermore, FT2 players performed more accelerations (p < 0.05; ES = -0.82 to -1.01) and decelerations (p < 0.01; ES = -1.00) in the mid-high intensity zones than FT1 players. While the greater impairment of FT1 players may have influenced their lower physical responses in competition compared to FT2 and FT3 players, the absence of differences between FT2 and FT3 classes is a novel aspect that requires further scientific investigation.

19 The Royal Netherlands Football Association (KNVB) relative age solutions project-part one: a call to action

Reference: Front Sports Act Living. 2025 Apr 10:7:1546829. doi: 10.3389/fspor.2025.1546829. eCollection 2025.
Authors: Adam Leigh Kelly, Frederike Zwenk, David Mann, Jan Verbeek
Download link: https://pmc.ncbi.nlm.nih.gov/articles/PMC12018424/pdf/fspor-07-1546829.pdf
Summary: Despite its widespread prevalence in youth soccer, there seems to be no widely implemented intervention to moderate or overcome Relative Age Effects (RAEs). The purpose of this study was a call to action for stakeholders to propose relative age solutions to the Royal Netherlands Football Association (KNVB). The call to action consisted of a standardised, open-access questionnaire that contained questions focussed on: (a) the mechanisms of the proposal, (b) hypothesised effects, and (c) reference to empirical findings. Following the initial screening of 185 submissions, a total of 143 eligible proposals were included. Each proposal was categorised by two project members based on a taxonomy to classify different approaches designed to reduce RAEs by: (a) altering the behaviour of observers, (b) implementing rules when selecting teams, or (c) adjusting competition structures. From this, 13 lower-order independent solutions were categorised. Interestingly, whilst no new suggestions outside the existing literature were proposed in any of the submissions, only two have been empirically tested in soccer. Overall, the results present a useful first step in identifying possible relative age solutions. Due to the number of proposed solutions and their anecdotal nature, the next step for the KNVB was to utilise the knowledge of experts in the field via an adapted e-Delphi study to identify the most effective and feasible solutions to implement in practice (Part Two).