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 Seasonal Associations Between Isometric Strength and Dynamic Performance in Elite Youth Soccer Players

Reference: Int J Sports Physiol Perform. 2026 May 20:1-10. doi: 10.1123/ijspp.2025-0673. Online ahead of print.
Authors: Nikolaos D Asimakidis, Marco Beato, Chris Bishop, Anthony N Turner
Summary: The aim was to investigate within-player, longitudinal associations between global and hip-specific isometric strength and dynamic performance across a season in elite youth soccer players. In a repeated-measures observational design, 25 elite U19 male soccer players were assessed at preseason, midseason, and end of season. Global isometric strength was evaluated using the isometric mid-thigh pull (IMTP), while hip adduction and abduction strength were assessed via fixed-frame dynamometry. Dynamic assessments included the countermovement jump (CMJ), single-leg CMJ, linear sprinting (5-30 m), 505 test, and Bronco test. Within-player associations were examined using repeated-measures correlation, accounting for the nonindependence of repeated observations. Increases in IMTP absolute and relative peak force were associated with improvements in CMJ jump height and peak power (rrm = .50 to .62) and faster 505 change of direction time (rrm = -.32 to -.44). No meaningful associations were observed between IMTP strength and unilateral jumping, linear sprinting, change of direction deficit, or endurance performance. Changes in isometric hip abduction strength were associated with CMJ performance (rrm = .28 to .53) and 505 change of direction time (rrm = -.29 to -.41), whereas isometric hip adduction strength showed no significant associations with any dynamic outcomes. Longitudinal changes in isometric strength were most strongly associated with dynamic tasks sharing similar biomechanical and kinetic demands, particularly those requiring high vertical or braking force production. These findings reinforce isometric testing as a low-fatigue indicator of force capacity and robustness, while indicating that such measures should complement, rather than replace, dynamic assessments within a comprehensive performance monitoring framework.

2 Correction: Acute beetroot juice supplementation enhances short duration high-intensity exercise performance and influences muscle oxygenation in football players

Reference: Sci Rep. 2026 May 18;16(1):15341. doi: 10.1038/s41598-026-53213-z.
Authors: Melike Nur Eroglu, Beril Kose, İpek Eroglu Kolayis, Bahtiyar Haberal
Download link: https://pmc.ncbi.nlm.nih.gov/articles/PMC13184239/pdf/41598_2026_Article_53213.pdf

3 A Semi-Markov framework for modeling football possessions and temporal expected threat

Reference: Sci Rep. 2026 May 18. doi: 10.1038/s41598-026-52938-1. Online ahead of print.
Authors: Sebastian Le Coz, Firas Boustila, Frank Imbach
Download link: https://www.nature.com/articles/s41598-026-52938-1_reference.pdf
Summary: This study presents a spatio-temporal semi-Markov framework to model football possessions and evaluate scoring probability within specific time windows. Current possession-value models, such as Expected Threat (xT), typically treat football as a memoryless Markov process where event timing is ignored. Our framework addresses this by jointly representing action type, spatial location, and non-exponential sojourn times. We estimate transition probabilities over a [Formula: see text] pitch grid and model event durations using Accelerated Failure Time models conditioned on distance and angle to the middle of the goal posts and next event. By using a quantile based criterion to select distributional families, we find that different transitions follow fundamentally different patterns. This contradicts the single-family assumptions used in prior research. We introduce a temporal xT metric that computes the probability of scoring within a fixed time horizon via backward induction. Evaluated on Ligue 1 and EURO event data, our model consistently outperforms a memoryless baseline on AUC and Brier score. We conclude that while infinite-horizon Markov models remain suitable for general play, temporal xT is the essential tool for time-critical decision support where the remaining clock is a binding constraint. This model provides an interpretable and data-driven foundation for analytics that accounts for how action duration directly affects scoring opportunities.

4 The Hourglass Sign on Optical Coherence Tomography in Soccer-Related Blunt Ocular Trauma

Reference: J Vitreoretin Dis. 2026 May 19:24741264261448444. doi: 10.1177/24741264261448444. Online ahead of print.
Authors: William Carrera, Danny A Mammo, Zaid Mammo , Andrew Lin, J Michael Jumper, Daniel A Brinton, Jesse J Jung
Summary: The aim was to describe the optical coherence tomography (OCT) findings in a series of patients following blunt trauma from a soccer ball. A retrospective case series was performed of 7 patients presenting with macular commotio. Spectral-domain OCT demonstrated foveal hyperreflectivity with an hourglass configuration in all cases. Other OCT findings included irregularity of the outer retinal layers and angular sign of Henle fiber layer hyperreflectivity. These imaging findings resolved within 2 to 6 weeks. The mean final best-corrected visual acuity was 20/20. Blunt trauma from a soccer may produce a characteristic foveal pattern of hyperreflectivity, for which we propose the term „hourglass sign“ in the setting of macular commotio. This configuration likely reflects the underlying anatomy of the foveal Müller cell cone and may represent a forme fruste macular hole without associated vitreomacular traction. The visual prognosis appears excellent.

5 The psychological characteristics behind talented soccer players: a systematic review with meta-analysis

Reference: Front Psychol. 2026 May 6:17:1821294. doi: 10.3389/fpsyg.2026.1821294. eCollection 2026.
Authors: Filipe Casanova, José Afonso, Alberto Pompeo, José Vilaça-Alves, Nuno Domingos Garrido, Everton Luis Rodrigues Cirillo, Rodrigo Ramirez-Campillo, Pedro Silva, André Barreiros
Summary: Soccer performance depends on a long-term process, with the psychological characteristics of young talented players being influential. This meta-analytic review synthesizes research that examined the psychological factors associated with talented soccer players, providing guidance for future studies. This study asked whether psychological factors are associated with future talent-like performance in young football players. We identified 4,015 records by searching PubMed, Scopus, and Web of Science. Of the 1,511 records screened, only 12 studies were included, as they were designed to be longitudinal and covered 3,748 players across recreational to elite levels. Risk of bias was assessed using the Risk of Bias Assessment Tool for Nonrandomized Studies, and certainty of evidence was judged with the GRADE framework. The findings suggest that greater values of achievement motive correlated positively with future talent-like performance; however, the pooled effect size was merely trivial (g = 0.198, 95% CI: 0.003-0.378) and heterogeneity was large (I 2 = 78.5%), likely reflecting differences in measurement tools, sample characteristics, and performance indicators. No other psychological construct could be meta-analysed due to insufficient and heterogeneous data, and overall certainty of evidence for all outcomes was rated very low. Other psychological characteristics such as mental toughness, grit, and resilience may play a functional role in talent development, but their isolated prognostic value for future performance appears small, inconsistent, and highly sensitive to methodological choices. In the future psychological factors should therefore not be used as standalone criteria for talent selection or deselection, but rather integrated within multidimensional, longitudinal assessment frameworks rather than solely cross-sectional designs, that combine technical, tactical, physical, and contextual information. Systematic review registration: 10.17605/OSF.IO/J4EPT.

6 Effect of Concurrent Power and Sprint Training on Physical Fitness in Well-Trained Youth Soccer Players: A Pilot Study

Reference: J Strength Cond Res. 2026 May 22. doi: 10.1519/JSC.0000000000005449. Online ahead of print.
Authors: Andreas Kyriacou-Rossi, Demetris Ieronymides, Andreas Hadjipantelis et al.
Summary: The purpose of the study was to investigate the effect of 5-week concurrent power-sprint training on power, repeated sprint ability (RSA), and aerobic capacity in well-trained youth soccer players. Sixteen male players (15.9 ± 0.5 years; height: 173.8 ± 5.0 m; mass: 65.3 ± 8.2 kg) participated in the study. After baseline evaluation, players were matched and divided into the concurrent (Conc) and the compound (Comp) groups. Players in the Conc group performed power-sprint training in the same training session, while the Comp group performed power and sprint training the following day. At the beginning and end of the 5-week training program, measurements included body composition, flexibility, countermovement (CMJ) and drop jumps (DJ), isometric mid-thigh pull (IMTP), 5-step long-jump, 0-30 m linear sprint, t test agility, RSA, and 30-15 intermittent fitness test (IFT). No changes were found for body composition and flexibility, although both groups improved CMJ height (Conc: 6.4%, p < 0.000; Comp: 5.6%, p < 0.001) and DJ reactive strength index (Conc: 38.2-42.5%, p < 0.000; Comp: 27.5-44.7%, p = 0.001), but only Conc increased IMTP (8.6%, p = 0.014). Five-step long-jump increased for both groups (Conc: 2.8 ± 2.6%, p = 0.027; Comp: 3.3 ± 3.6%, p = 0.012) but no chances were observed for 0-30 m linear sprint and agility. Repeated sprint ability increased in both groups, but Conc induced greater increases than Comp (p < 0.001). Significant increases were found for 30-15 IFT V̇o2max (Conc: 4.8%; Comp: 4.0%) for both groups. In conclusion, concurrent power-sprint training improves strength, power, and aerobic fitness in youth soccer players. Implementing both modalities within the same training session yields superior gains particularly in RSA, a key factor in soccer performance.

7 Detection of season-long post-concussion motor deficits in female soccer players using a 3D goal equivalent manifold framework

Reference: Sci Rep. 2026 May 22. doi: 10.1038/s41598-026-49059-0. Online ahead of print.
Authors: Xiong Zhao, Reza Rahimi, Janie Cournoyer, Allison Clouthier, Ryan B Graham
Summary: This study examined whether a geometry-based movement variability framework (3D Goal Equivalent Manifold, GEM) could detect persistent motor control deficits across a competitive season in female soccer players with a history of concussion, and compared its performance with the traditional 2D GEM approach. Twenty-five female varsity soccer players (11 with concussion history within 3 years, 14 without) completed bilateral bodyweight squats synchronized with a metronome (40 beats per minute) at pre-, mid-, and post-season. Whole-body kinematics were captured using a markerless motion capture system. 3D GEM analysis decomposed variability into task-relevant and task-irrelevant components, producing a 3D performance index (PI) and temporal persistence metrics (λ). Players with concussion history exhibited significantly lower 3D PI scores (M = 9.48 ± 1.60) compared to those without (M = 16.26 ± 2.45; p = 0.017), with no significant seasonal changes or interactions. No significant differences emerged for temporal persistence metrics, although the concussion group consistently showed trends toward less effective regulation in task-relevant dimensions. The 3D GEM approach effectively identified persistent motor control deficits in female soccer players with concussion histories, underscoring its potential for clinical assessments and monitoring throughout rehabilitation and return-to-play programs.

8 Comparisons of Lower-Body Muscular Function, Anthropometrics, and Body Composition Between Divisions I and III Collegiate Soccer Players

Reference: J Strength Cond Res. 2026 May 29. doi: 10.1519/JSC.0000000000005512. Online ahead of print.
Authors: Alexander H K Montoye, Matthew Przepiora, Toby Stauffer et al. Summary: This study compared anthropometric characteristics, lower-body muscular function, and body composition outcomes in collegiate Division I (DI) and Division III (DIII) men’s and women’s soccer players. Cross-sectional testing was conducted in 49 men and 43 women from 2 National Collegiate Athletic Association DI and DIII teams. Outcome measures included anthropometrics (height, weight), muscular function (countermovement jump height and power, eccentric hamstring maximal force, hip abduction, and adduction maximal force), and body composition (women only; total and regional bone mineral density, fat mass, lean mass). Two-way analysis of variance compared outcomes between divisions and across player positions. DI women were taller (∼1.7 cm) than DIII women, but no other anthropometric measures differed between divisions. DI women had significantly greater countermovement jump height (∼8 cm; 35%), absolute and relative jump power (∼12%), hip abduction strength (∼37%), and torso lean mass and lower body fat (23.6 vs. 28.4%) than DIII women. DI women had significantly lower bone mineral density in the arms and ribs and a lower Z-score (0.8 vs. 1.4), though all values were within healthy ranges. DIII men had higher absolute and relative jump power (∼5-9%) than DI men, particularly because of defender-specific differences, while other muscular function measures did not differ by division. In summary, some division- and position-level differences existed in lower-body muscular function and body composition, particularly among women. These findings highlight the importance of evaluating athletic performance alongside health-related indicators and support sex- and position-specific approaches to athlete monitoring across collegiate divisions.

9 Passive Heating Via Heating Pads Improves Vertical Jump and Agility Performance in NCAA Division III Soccer Players

Reference: J Strength Cond Res. 2026 May 29. doi: 10.1519/JSC.0000000000005502. Online ahead of print.
Authors: Nigel C Jiwan, Keegan J DeKuiper, Lauren A Sysol, Gabrielle E Chabala, Pietro A Costa
Summary: Passive heating may enhance performance by increasing blood flow, improving nerve conduction, and stimulating calcium release. Although most studies focus on saunas or hot water immersion, research on heating pads (HP) remains limited. Thus, this study aims to investigate the effect of HP on athletic performance in soccer players. Nineteen male (n = 10) and female (n = 9) soccer players completed 2 identical testing sessions in a randomized, counterbalanced design. HP was applied to both thighs and set to 66°C in the passive heat treatment (PHT) and maintained at body temperature in the sham condition. Skin temperature was taken before (Pre) and after (Post) HP application. After heating, subjects completed 3 performance tests: passing accuracy, vertical jump, and agility t test. Peak power was derived from vertical jump height (VJH). The alpha level was set at p ≤ 0.05. PHT significantly increased thigh skin temperature, improved VJH, peak power, and agility times, while no differences were observed for passing accuracy. PHT improved VJH and agility times in soccer players, supporting HP as an accessible and effective preactivity strategy to enhance performance.

10 A Comparison of the Consistency of Adaptive Changes in Biomotor Abilities Induced by Interval Training Individualized Using the 30-15 Intermittent Fitness Test Vs. Time-Matched Small-Sided Games in Well-Trained Soccer Players

Summary: J Strength Cond Res. 2026 May 29. doi: 10.1519/JSC.0000000000005486. Online ahead of print.
Authors: Lu Lyu, Xue-Meng Wu, Zhen Li, Xin-Min Qin, Yang He
Summary: Adaptive changes from specific interventions are typically assessed by looking at the average responses of a group, with the assumption that these averages represent the adaptations of each individual. However, in practice, athletes exhibit varying responses to a given intervention. This study aimed to compare the effects of interval interventions prescribed using fixed reference intensities and small-sided games (SSG) on the homogeneity of adaptive responses in biomotor abilities in well-trained soccer athletes. Thirty national-level players were equally randomized to 2 high-intensity interval intervention groups individualized using 30-15 Intermittent Fitness Test (G-VIFT [2 sets of 5- to 8-minute intervals, comprising 15 seconds of running at 95% of VIFT followed by 15 seconds of passive recovery]), and time-matched SSG (4 sets of 2.5-4 minutes 3 v 3 efforts), and an active control group (CON), each of 10. Biomotor abilities including linear sprint speed, change of direction, jumping ability, muscular endurance, Yo-Yo intermittent recovery level 2 test, and anaerobic power were evaluated before and after an 8-week training period. Interindividual variability was examined using residual changes and coefficients of variation. Our results indicated that both G-VIFT and SSG groups significantly enhanced measures of biomotor abilities over the training period (p < 0.05). Comparative analysis indicated G-VIFT results in more homogenous adaptations in average power output and the subjects‘ ability to repeatedly perform and recover from intense exercise compared with SSG. Overall, individualizing high-intensity interval training using VIFT promotes more consistent adaptations in measures of anaerobic power and exercise tolerance compared with SSG.

11 The Effect of High-Velocity Elastic Band Training on Physical Performance in Youth Soccer Players

Reference: J Strength Cond Res. 2026 May 29. doi: 10.1519/JSC.0000000000005515. Online ahead of print.
Authors: Dominykas Bartusevičius, Jūratė Stanislovaitienė, Sigitas Kamandulis, Daniele Conte
Summary: The purpose of this study was to evaluate the effectiveness of a high-velocity elastic band training (HVEBT) program in youth soccer players. Eighteen male outfield players (age = 15.5 ± 0.4 years, stature = 175.1 ± 6.1 cm, body mass = 68.9 ± 7.3 kg, training experience = 9.9 ± 1.1 years, maturity offset = 1.8 ± 0.4 years) were recruited for the study. Players were randomly assigned to the experimental (HVEBT) and control groups. The study lasted 20 weeks (2 times per week) and consisted of 6 lower limb exercises targeting the main lower limb muscle groups (i.e., knee and hip flexors, extensors, and hip adductors) performed before the regular soccer training session; the control group did no additional activity. Before and after the experimental period, players‘ lower limb peak concentric torque measured with an isokinetic dynamometer at 180°·s-1, Y-balance composite score for dominant (YBT.D) and nondominant (YBT.ND) leg, countermovement jump (CMJ) height, the 10 and 30 m linear sprint time, ball-kicking velocity for dominant (BKV.D) and nondominant (BKV.ND) legs were assessed. Results revealed time*group interaction for YBT.D, YBT.ND, CMJ, 10-m sprint time, and BKV.ND (ηp2 =0.438-0.523, moderate), with post hoc within-group changes only in the HVEBT group, ranging from moderate to very large (g = -2.22 to 1.85). Furthermore, within-group changes for BKV.D in both control (g = -3.04 [-4.64 to -1.44]) and HVEBT groups (g = -2.52 [-3.88 to -1.15]) were very large. Our findings suggest that a 20-week in-season HVEBT exercise program, in addition to regular soccer training, is effective in improving sprinting, jumping, ball-kicking, and dynamic balance performance in postpubertal youth soccer players.

12 Effects of Combined Training on Physical Fitness According to Maturity in Male Youth Soccer Players

Reference: J Strength Cond Res. 2026 May 28. doi: 10.1519/JSC.0000000000005506. Online ahead of print.
Authors: Firas Zghal, Serge S Colson, Mohamed A Bouzid et al.
Summary: The aim of this study was to investigate whether the adaptations related to combined resistance and plyometric (PLYO)/sprint training on measures of physical fitness differed according to maturity status. Thirty-five young male soccer players were assigned to 2 experimental groups, labeled circa-peak-height-velocity [PHV] (n = 13, age 14.2 ± 0.2 years, predicted from/to age at PHV [PAPHV] = +0.1 ± 0.3 years) and post-PHV (n = 12, age 17.2 ± 0.4 years, PAPHV = +2.9 ± 0.5 years), and an active control group (CONT; n = 10, age 15.8 ± 1.7 years, PAPHV = +1.1 ± 1.3 years). Two weekly sessions of combined resistance training and PLYO/sprint training, or soccer training sessions, were added to the regular soccer-training program for the experimental and CONT groups, respectively. Before and after 7 weeks of training, absolute peak torque, peak torque normalized to thigh volume, and absolute and relative (normalized to peak torque) rate of torque development (RTD) during maximal voluntary isometric contraction of the knee extensors were assessed. In addition, vertical jump (squat [SJ], countermovement [CMJ], drop jump [DJ]), linear sprint (5, 10, 20 m), and change-of-direction (CoD) speed tests (505 test) were performed. An analysis of covariance with group as between-subject comparator and baseline data as a covariate was computed using delta values. Significant differences were observed for absolute peak torque (p < 0.001; η2 = 0.62), peak torque normalized to thigh volume (p < 0.001; η2 = 0.58), absolute RTD (p < 0.001; η2 = 0.64), and relative RTD (p < 0.01; η2 = 0.26), vertical jump performance (SJ: p < 0.001; η2 = 0.54, CMJ: p < 0.001; η2 = 0.66), and linear sprint (5-m: p < 0.001; η2 = 0.55, 10-m: p < 0.001; η2 = 0.36) and CoD speed (p < 0.001; η2 = 0.41) with greater percentage changes for the circa- compared with the post-PHV group. Our results suggest that the extent of adaptations to combined resistance and plyometric (PLYO)/sprint training is influenced by the individuals‘ maturity status. From a practical perspective, the findings of this study suggest that combined resistance and plyometric/sprint training could be particularly useful when performed around PHV, a maturational status at which greater neuromuscular adaptability may enable further gains in physical fitness.

13 Comparison of Isolated ACL and Combined ACL/MCL Injuries in Professional Soccer and Rugby Players: Return to Play and Career Longevity Outcomes

Reference: Am J Sports Med. 2026 May 29:3635465261448236. doi: 10.1177/03635465261448236. Online ahead of print.
Authors: Wahid Abdul, Mary Jones, David Haslhofer, Arman Motesharei, Simon Ball, Andy Williams
Summary: Combined injury of the anterior cruciate ligament (ACL) and medial collateral ligament (MCL) is the most common combined knee ligament injury. However, there is only limited evidence, and no clear consensus, on the optimum management of these injuries. The aim was to determine the return-to-play (RTP) rate and time, career longevity, and rerupture rates of elite soccer and rugby players after combined ACL+MCL injuries and to compare RTP rate, career longevity, and rerupture rates in players with ACL+MCL injury versus those who have isolated ACL injuries. A consecutive series of professional soccer and rugby players who underwent primary ACL reconstruction (ACLR), with and without MCL injury, and treatment between 2015 and 2022 were retrospectively reviewed. Indications for MCL surgery were medial opening on valgus stress in full extension and/or grade II/III valgus laxity at 30°, positive dial test for anteromedial rotatory instability (AMRI), a positive Slocum test in external rotation, or a „Stener-like“ lesion or intra-articular MCL incarceration. RTP was defined as first competitive match appearance. Data were extracted from clinical notes, contact with teams‘ medical staff, and publicly available databases. A total of 230 athletes (238 knees) were included; 97 (40.8%) had ACLR only, 97 (40.8%) had ACLR + nonoperative MCL management, and 44 (18.5%) had ACLR + MCL reconstruction. Of these, 135 (56.7%) were soccer and 103 (43.3%) were rugby players. Mean follow-up was 5.8 ± 2.4 years with a minimum of 3.4 years. Overall RTP rate was 95.4% (96.3% soccer, 94.2% rugby). This was similar in the ACLR-only group, ACLR + nonoperative MCL group, and ACLR + MCL reconstruction group (P = .06). Mean RTP time was 12.0 ± 4.4 months; 11.8 months for ACLR only, 12.2 months for ACLR + nonoperative MCL, and 11.9 months for ACLR + MCL reconstruction (P = .88). Overall, 2- and 5-year still-playing rates were 79.8% and 67.7%, respectively, with no difference between subgroups at 2 (P = .55) or 5 years (P = .53). RTP times and career longevity after ACLR with and without MCL injury in professional soccer and rugby players are similar.

14 The impact of mental fatigue on repeated sprint and change-of-direction performance in soccer

Reference: Front Psychol. 2026 May 13:17:1842345. doi: 10.3389/fpsyg.2026.1842345. eCollection 2026.
Authors: Wei Yang, Ting Chen, Gong Chen
Download link: https://www.frontiersin.org/journals/psychology/articles/10.3389/fpsyg.2026.1842345/full
Summary: Elucidating the impact of mental fatigue (MF) on physical performance in soccer is essential for optimizing athlete assessment, training, and competition strategies. However, the relationship between MF and both repeated sprint (RSA) and repeated change-of-direction performance (RCOD) remains unclear. Therefore, the aim of this study was to investigate the effects of MF on RSA and RCOD performance in soccer players. In a randomized, counterbalanced crossover design, 18 male amateur soccer players completed two experimental sessions, separated by a minimum 48 h washout period: (1) a 45-min Stroop task to induce mental fatigue (MF condition), and (2) watching a 45-min emotionally neutral video as control (CON condition). Following each treatment, participants performed a RSA test and a RCOD test. Measured variables included: Visual Analogue Scale for mental fatigue (VAS-MF), Brunel Mood Scale for fatigue (BRUMS-F), and vigor (BRUMS-V) (assessed pre- and post-treatment); average heart rate (HRave) during the treatment, RSA and ROCD test; Visual Analogue Scale for mental effort (VAS-ME) (assessed post-treatment); and blood lactate (BLA) along with ratings of perceived exertion (RPE) following each performance test. Pre-treatment VAS-MF and BRUMS-F, HRave during the treatment did not differ significantly between conditions (p = 0.155, 0.429 and 0.262, respectively), post-treatment, the MF condition resulted in significantly higher VAS-MF, VAS-ME and BRUMS-F than control condition (p = 0.002, <0.001 and 0.05, respectively). The RSA performance [p = 0.885, 0.714 and 0.483 for total time (TT), best time (BT) and fatigue index (FI)] and BLA, RPE during two tests were not significantly affected by MF, however the RCOD performance was significantly reduced in the condition of MF (p = 0.006 and 0.007 for TT and BT). MF did not impair RSA performance but significantly reduced RCOD performance in soccer.

15 Practice (Doesn´t) Make Perfect Shooters: The Influence of Experience on Penalty Execution in Elite Soccer

Reference: J Hum Kinet. 2025 Nov 19:102:215-226. doi: 10.5114/jhk/205224. eCollection 2026 Apr.
Authors: Rubén Maneiro, Antonio Ardá, José Luís Losada, Iyán Iván-Baragaño
Summary: The aim of this study was twofold: firstly, to identify the variables associated with the experience of penalty shooters, and secondly, to understand the interaction of contextual variables and penalty execution that differentiated experienced from inexperienced players. To achieve this, a systematic observational methodology was employed to analyze 1,589 penalty kicks in various international club and national team competitions for men. The analyses were conducted using contingency tables and the chi-square statistic, as well as decision trees and binary logistic regression, to address the second objective. Categorizing players as experienced or inexperienced was based on their role as penalty kick takers in the team. Considering experience, statistically significant differences were found in contextual variables such as the specific position, age, timing, and match status. Similarly, differences were found in the shooter’s running approach and kick height. At a multivariate level, both classification models showed significant differences in shooting patterns based on experience: players differed in terms of match timing, the specific position, the running approach, and the penalty outcome. The results of this study demonstrated differences between experienced and inexperienced players, highlighting the need to: i) delve deeper into research on this specific soccer action, and ii) enhance training of such actions among a greater number of players, not solely relying on experienced players for their execution.

16 How Different Physical Qualities Influence Repeated Sprint Ability Tests in Elite Youth Soccer Players?

Reference: J Hum Kinet. 2025 Sep 23:102:183-194. doi: 10.5114/jhk/203832. eCollection 2026 Apr.
Authors: Alejandro Sal-de-Rellán, Mehdi Ben Brahim, Víctor Martín, Najet Zidi, Ariadna Hernaiz-Sánchez
Download link: https://johk.pl/wp-content/uploads/2026/05/14.pdf
Summary: The aim of this study was to examine the relationships between different repeated sprint ability (RSA) tests and to determine whether all RSA tests were related to the same physical qualities. Twenty-five young elite soccer players (age: 17.1 ± 0.9 years; body height: 172.5 ± 4.6 cm; body mass: 68.1 ± 3.9 kg) participated in this study. Participants completed five RSA tests (i.e., RSA 20 + 20, RSA-linear, RSARANDOM, RSA 15 + 15, and RSA-Curve), a linear sprint test (i.e., a 30-m linear sprint with split times recorded at the 5th and the 10th m ), a curve sprint test (CV_Best and CV_Worst), a change of direction (COD) test, and vertical jump tests (i.e., SJ, CMJ and DJ tests) during a training camp. The main results showed moderate relationships between RSA-RANDOM and RSA 20 + 20 (r = 0.410; p < 0.05) and between RSA-Linear and RSA 15 + 15 (r = 0.475; p < 0.05). In addition, negative relationships were observed between RSA-Curve and the other RSA tests. Additionally, the RSA-Linear test obtained moderate relationships with a 10-m sprint (r = 0.485; p < 0.05), CV_Best (r = 0.484; p < 0.05), CV_Worst (r = 0.410; p < 0.05) and the CMJ (r = 0.403; p < 0.05), and the RSA-RANDOM test with COD (RSAtotal: r = 0.414; p < 0.05; RSAbest: r = 0.489; p < 0.05). These findings may help coaches and sports scientists optimize training and performance assessment by identifying the most suitable RSA test for specific variables. In addition, training focused on improving different physical qualities can positively impact RSA performance.

17 Match-Related Acute and Residual Changes of Hip-Adduction Strength in Youth Soccer Players

Reference: J Hum Kinet. 2025 Sep 23:102:75-86. doi: 10.5114/jhk/204377. eCollection 2026 Apr.
Authors: Maziar J Hamad, Pedro E Alcaraz, Kristian Thorborg, Antonio Martínez Serrano, Konstantinos Spyrou
Download link: https://jhk.termedia.pl/pdf-204377-128738?filename=Match_Related%20Acute%20and.pdf
Summary: The aim of this study was to investigate the changes in isometric hip-adductor strength (ADDiso) following official matches in youth soccer players. In this observational study, eighteen young soccer players (age: 18.03 ± 0.53 years; body mass: 69.03 ± 5.70 kg; body height: 1.75 ± 0.06 m) participated. ADDiso and match external demands were measured using a hand-held dynamometer and foot-mounted inertial measurement units, respectively, during official matches (match 1, M1 and match 2, M2) at pre-match (Pre), post-match (Post), and 24 hours post (+24h). In M1, ADDiso decreased significantly from Pre to Post (p = 0.003, ES = -1.14), then increased Post to +24h (p = 0.002, ES = 1.49). In M2, ADDiso decreased significantly Pre to Post (p < 0.001, ES = -1.41) then increased Post to +24h (p < 0.001, ES = 2.39). Non-significant differences were found Pre to +24h for M1 (p = 1.00, ES = 0.09), while the M2 +24h time point was significantly higher than Pre (p = 0.039, ES = 0.83). Regarding external match demands, players performed significantly higher releases per min in M1 compared to M2 (p = 0.024, ES = 1.10); conversely, intense speed changes per min (accelerations and decelerations) were significantly higher in M2 (p = 0.050, ES = -0.93). ADDiso decreased post-match on average between 12 and 22% in this sample of youth soccer players. The average reduction in strength was larger after M2 which may be explained by different external demands like more intense speed changes. Further research into different game intensities and their potential influence on hip-adduction strength seems relevant.

18 Dynamics of Change in Aerobic Capacity in 7-12 Year-Old Children Playing Soccer in Relation to Training Load

Reference: J Hum Kinet. 2025 Sep 23:102:103-116. doi: 10.5114/jhk/207460. eCollection 2026 Apr.
Authors: Cezary Bejm, Andrzej Klimek
Download link: https://jhk.termedia.pl/pdf-207460-128741?filename=Dynamics%20of%20Change%20in.pdf
Summary: This study monitored changes in aerobic capacity in 7-12-year-old youth soccer players over three years, dividing them into two groups: Group 1 (ages 7-10) and Group 2 (ages 10-12). Key variables, maximum oxygen uptake (VO2max) and the anaerobic threshold (AT), were measured using an incremental treadmill test. The data analysis revealed that training did not significantly influence aerobic capacity, with no strong correlation between training intensity and VO2max, except between ages 7 and 8 (r-Pearson coefficient between -0.52 and 0.66). VO2max differences between groups (Group 1: age 7, 46.2 ± 4.0; age 8, 59.1 ± 4.5; age 9, 63.4 ± 6.8; age 10, 59.5 ± 4.2 ml/kg/min; Group 2: age 10, 53.1 ± 8.5; age 11, 61.5 ± 5.1; age 12, 62.7 ± 5.7 ml/kg/min) appeared to be more related to individual developmental paths and genetics than to training or pubertal stages. There was no significant effect of training on the anaerobic threshold, indicating stability during submaximal efforts across the observed period. However, aerobic capacity improvements were noted, particularly in prolonged exercise duration and increased maximal aerobic speed (MAS), likely due to enhanced running efficiency and motor coordination. MAS for Group 1 increased from 8.7 km/h at age 7 to 9.5 km/h at age 10, while for Group 2, it rose from 8.5 km/h at age 10 to 9.2 km/h at age 12. This suggests significant potential for aerobic development during these early training years.

19 A 3-day step taper enhances explosive power, repeated sprint, and small-sided game performance in soccer

Reference: Front Sports Act Living. 2026 May 13:8:1811250. doi: 10.3389/fspor.2026.1811250. eCollection 2026.
Authors: Mohamed Saifeddin Fessi, Mohamed Elloumi, Mohamed Amine Bouzid, Mehdi Ben Brahim, Wassim Moalla
Download link: https://www.frontiersin.org/journals/sports-and-active-living/articles/10.3389/fspor.2026.1811250/full
Summary: This study aimed to investigate the effects of a three-day step taper on lower-limb explosive power, repeated-sprint performance, and physical and physiological parameters during sport-specific exercises in professional soccer players. The study involved 26 outfield professional soccer players from the same team (age: 28.7±4.3 years; body mass: 71.8±7.2 kg; height: 173.7±4.3 cm). Following a 4-week mesocycle of progressive training load, players were randomly assigned to a taper group (TG; n = 13), which underwent a three-day step taper with a 50% reduction in training duration while maintaining intensity, and a control group (CG; n = 13), which maintained their routine. Both groups performed two Countermovement jumps with arm swing (CMJAS), a 5×30-m repeated-sprint test, and a Small-Sided Game (SSG) before and after the step tapering. Training load was monitored using the session rating of perceived exertion (sRPE) method. The results indicated that the TG improved CMJAS height (large effect; d = 1.5; p < 0.01) and decreased peak and total time during repeated sprints (small effect; d = 0.3; p < 0.05). It also enhanced the total covered distance (small effect; d = 0.3; p < 0.05), as well as accelerations and decelerations during the SSG (moderate effect; d = 0.8 and d = 0.6, respectively; p < 0.05). In contrast, the CG showed significant decreases in CMJAS height (moderate effect; d = 1; p < 0.01) and increases total sprint times (small effect; d = 0.4; p < 0.05), indicating reduced performance, with no significant changes in SSG metrics. The study indicates that a 3-day step taper with a 50% reduction in training duration, while keeping intensity and frequency, effectively improves repeated-sprint ability and explosive power in professional soccer players, without performance loss from prior high training loads.

20 Cognitive-Motor Dual-Task Training (CMDT) Approaches for Performance, Recovery, Injury Prevention, Rehabilitation, and Return to Sport in Soccer: A Narrative Review with Practical Recommendations for Soccer Clubs

Reference: J Funct Morphol Kinesiol. 2026 May 15;11(2):196. doi: 10.3390/jfmk11020196.
Authors: Asaf Shalom, Roni Gottlieb, Julio Calleja-Gonzalez
Download link: https://www.mdpi.com/2411-5142/11/2/196
Summary: This narrative review explores the potential role of cognitive-motor dual-task training (CMDT) approaches within training methods used in sports clubs, with particular emphasis on soccer clubs, to support performance enhancement, recovery, and injury prevention; improve agility, decision making, and functional readiness; and enhance training quality and specificity. The review discusses how CMDT may be integrated as part of the broader and more comprehensive planning of the club’s full training program, including during the preseason period, as part of preparation for training and competition, within recovery sessions, during periods of high load, and throughout the rehabilitation process and the transition back to team training and contact exposure, while also potentially contributing to variety, mental stimulation, enjoyment, and player engagement. The review also emphasizes the importance of implementing CMDT within a coordinated professional framework, through collaboration and synchronization within the professional and medical staff of the club, and in broad alignment with club goals, player characteristics, and sport-specific demands. The key insight is that CMDT has the potential to serve as a practical, complementary approach that helps bridge the gap between controlled training and rehabilitation settings and the dynamic demands of soccer participation. Based on this review, practical recommendations and future research directions are presented, while emphasizing that CMDT should be applied with caution, through gradual and context-specific progression, and in line with established training, recovery, and rehabilitation principles.

21 Sleep Hygiene Improves Aerobic and Anaerobic Performance Independent of Cortisol Mediation in Female Collegiate Soccer Players

Reference: J Funct Morphol Kinesiol. 2026 May 7;11(2):187. doi: 10.3390/jfmk11020187.
Authors: Elric Pretorius, Mark Kramer, Adele Broodryk
Download link: https://www.mdpi.com/2411-5142/11/2/187
Summary: Sleep hygiene protocols (SHPs) have been shown to improve sleep and stress regulation; however, the role of cortisol in shaping downstream physiological and performance adaptations remains unclear. This study primarily examined the effects of a short-term SHP on sleep duration and salivary cortisol responses across resting, pre-exercise, and post-exercise states in female collegiate soccer players and, secondarily, whether cortisol statistically mediated selected aerobic and anaerobic performance outcomes. Fourteen players (22.1 ± 3.3 y; 157.8 ± 6.0 cm; 53.5 ± 3.9 kg) completed a randomised, counterbalanced crossover study comparing habitual sleep (no sleep hygiene protocol; nSHP) with a comprehensive SHP incorporating environmental, behavioural, and educational strategies. Salivary cortisol was sampled one hour post-waking and 30 min pre- and 15 min post-exercise during standardised testing sessions. Performance outcomes included vertical jump, sprint performance (40 m and repeated sprints [RAST]), and the Yo-Yo Intermittent Recovery Test Level 1. Linear mixed-effects models assessed cortisol responses, and mediation analyses explored cortisol-performance relationships. After SHP, perceived (7.87 h vs. 6.5 h; p = 0.002, ESg = 1.0) and calculated sleep duration (8.5 h vs. 6.9 h; p = 0.004, ESg = 0.95) increased significantly. Cortisol was markedly lower following SHP at selected timepoints, including before RAST (-43.05%, p = 0.006, ESg = 0.84), with additional timepoint-specific, condition-dependent differences post-anaerobic and post-aerobic exercise (Δ = 7.37 and 5.98 nmol·L-1, respectively; p < 0.001). Vertical jump height demonstrated significant total (9.92 cm, p = 0.002) and direct effects (7.72 cm, p = 0.034), and peak repeated-sprint performance showed a significant direct effect (p = 0.026). Cortisol did not significantly mediate any performance outcomes (ACME p > 0.05). Short-term sleep hygiene is associated with increased sleep duration, timepoint-specific modulation of cortisol responses, and selected anaerobic performance benefits; however, these effects were not explained by measured cortisol responses and are unlikely to be sustained without ongoing reinforcement or support, particularly in athletic populations.

22 Velocity-Dependent Eccentric Knee-Flexion Isokinetic Assessment in Elite Professional Soccer Players: Reliability, Inter-Limb Asymmetry and Mechanical Characteristics

Reference: J Funct Morphol Kinesiol. 2026 Apr 30;11(2):184. doi: 10.3390/jfmk11020184.
Authors: Francisco Javier Nuñez, Marco Carletta, Gloria Picco, Reyes Adorna, Juan Luis Nuñez-González, Luis Suarez-Arrones
Download link: https://www.mdpi.com/2411-5142/11/2/184
Summary: The primary aim of this study was to compare eccentric knee flexion isokinetic performance at two commonly used angular velocities (60°·s-1 and 180°·s-1) between dominant and non-dominant limbs in healthy professional soccer players through the analysis of peak torque, mean peak torque, angle of peak torque, total work, and rate-of-torque-development-related variables. The secondary aim was to describe concentric knee extension and knee flexion strength variables assessed at 60°·s-1. Forty male professional soccer players performed concentric knee flexion-extension testing at 60°·s-1 and eccentric knee flexion testing at 60°·s-1 and 180°·s-1 using an isokinetic dynamometer. Peak torque (PT), mean peak torque (MPT), angle of peak torque (APT), total work (TW), and hamstrings: quadriceps ratios (H:Q ratios) were analyzed for dominant and non-dominant limbs. Inter-limb differences, repetition effects, and reliability indices were calculated. No significant inter-limb differences were observed for most variables (trivial-small effect sizes), except for higher eccentric TW at 180°·s-1 in the dominant limb (p = 0.009). Eccentric PT and MPT decreased at higher velocities in both dominant (p = 0.002 and p < 0.001, respectively) and non-dominant (p = 0.008 and p < 0.001, respectively) limbs, while APT shifted toward more flexed knee angles (p < 0.001). Reliability was good to excellent (ICC = 0.81-0.87), with low measurement error. Eccentric knee flexion assessment at 60°·s-1 and 180°·s-1 angular velocities provided different results in PT, MPT, and APT for the same group of players, supporting the use of more than one eccentric test for obtaining information about these variables in elite soccer.