To evaluate the growth, maturity and performance characteristics of select youth soccer players grouped by subsequent playing status as adults. Height, weight, skeletal and pubertal maturity status, and performances on jumping, speed and aerobic endurance tasks were measured in 1998-1999 for 135 players 11-12 (n=29), 14-15 (n=61) and 16-17 (n=45) years. Based on records of the Portuguese Soccer Federation for the 2018-2019 season, 63 of the players were not involved in soccer as adults, while 47 played at the amateur level and 25 played professionally. Among players 11-12 years, those playing professionally as adults performed significantly better in the jump and sprint compared to peers no longer playing, while among players 14-15 years, those playing professionally as adults were significantly taller and performed better in the sprint as youth. Among players 16-17 years, in contrast, those playing soccer as an amateur or professionally and those no longer involved as adults did not differ as youth in body size, skeletal and pubertal maturity status, and performances. Comparisons of the youth characteristics of those playing soccer as adults and those no longer involved indicated no consistent pattern in the three competitive age groups considered. Unfortunately, information on soccer-specific skills and coach perceptions of skills and characteristics of youth players was not available.
Background/Objectives: Soccer involves high physiological demands that induce neuromuscular fatigue, muscle damage, inflammation, and oxidative stress, impairing recovery between training sessions and competitions. Polyphenols have been proposed as a nutritional strategy to modulate these responses; however, evidence in soccer players is limited and heterogeneous. This systematic review aimed to synthesize the evidence on the effects of polyphenol supplementation on post-exercise recovery in adult male soccer players. Methods: A systematic review was conducted following PRISMA guidelines, with a protocol registered in the Open Science Framework. Randomized controlled trials (RCTs) evaluating polyphenol supplementation versus placebo on post-exercise recovery in adult soccer players were included. Searches were performed in PubMed, Scopus, Web of Science, and the Cochrane Library up to April 2026. Risk of bias was assessed using RoB 2, and certainty of evidence using GRADE. Due to heterogeneity, a qualitative synthesis was conducted. Results: Eight RCTs were included. Interventions involved tart cherry juice, pomegranate juice, beetroot juice, curcumin, and tea extracts. Evidence was inconsistent for biomarkers of muscle damage, inflammation, and oxidative stress, with most studies reporting no significant differences versus placebo. In contrast, beneficial trends for perceptual outcomes, particularly reduced muscle soreness and improved subjective well-being, were mainly observed in studies using tart cherry juice, beetroot juice, and curcumin. Evidence for oxidative stress and functional recovery was limited and heterogeneous. Certainty of evidence was low for most outcomes and very low for oxidative stress and functional recovery. Conclusions: Polyphenol supplementation, particularly tart cherry juice, beetroot juice, and curcumin, may improve perceptual recovery in adult male soccer players, particularly by reducing muscle soreness and enhancing subjective well-being. However, evidence on physiological biomarkers and functional recovery remains inconsistent and of low certainty. Further well-designed RCTs are required to establish robust recommendations in competitive soccer.
Shoulder dislocation injuries may require prolonged recovery and absence from play, with risks of recurrent instability. The impact of shoulder dislocation on return-to-play (RTP) time and player performance in professional soccer athletes remains poorly defined. To determine the rate and timing of RTP, risk of recurrence, and player performance after shoulder dislocation in elite professional soccer athletes. Descriptive Epidemiology Study. Professional soccer athletes who sustained a shoulder dislocation between 2010 and 2024 across the 5 major European soccer leagues with a minimum 1-year follow-up were identified using publicly available records. Injured athletes were matched by position, age, height, season, experience, and preinjury minutes played and compared to uninjured controls. RTP rates, recurrence, field time, and performance up to 4 seasons after injury were assessed. A total of 118 soccer athletes with shoulder dislocations were included (38% defenders, 23% attackers, 20% goalkeepers, and 19% midfielders). Mean age at time of injury was 26.2 ± 4.2 years. Overall, 87% returned to the same level within 2 seasons after shoulder dislocation. Injured athletes missed a median of 68 days and 10 games, with goalkeepers missing more days (124 vs 60, P < .001) and games (21 vs 8, P < .001) compared to outfield players. Recurrence occurred in 18% at a mean time of 2.6 ± 2.4 years, with a higher risk in athletes ≤25 years (26% vs 12%, P = .046). By treatment, 59% and 41% underwent operative and nonoperative management, respectively, with similar recurrence rates (17.1% vs 18.8%, P = .823) but longer time to recurrence in the operative group (3.82 ± 2.91 vs 1.41 ± 0.69 years, P = .009). Injured athletes played significantly fewer games, total minutes, and minutes per game during the index season and at 1 and 2 seasons after shoulder injury compared with matched controls. However, performance metrics and RTP rates in all seasons after injury remained comparable to matched controls across all positions and treatment groups. Professional soccer athletes returned to play at a high rate and a median of 68 days after shoulder dislocation, with an 18% recurrence rate. Despite reduced field time for up to 2 seasons after injury, overall player performance and RTP were not adversely affected.
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. 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. Case series; Level of evidence, 4. 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.
Bartusevičius, D, Stanislovaitienė, J, Kamandulis, S, and Conte, D. The effect of high-velocity elastic band training on physical performance in youth soccer players. J Strength Cond Res XX(X): 000-000, 2026-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.
Combined anterior cruciate ligament (ACL) and medial collateral ligament (MCL) injuries are common in professional sport, but there is little evidence available regarding the long-term impact of them on players' sporting careers. To determine the effect on return to play (RTP), career longevity, and match participation of male professional soccer and rugby players after primary ACL reconstruction (ACLR) and associated MCL injury, treated with operative or nonoperative management, by comparing each group with uninjured matched controls. Cohort study; Level of evidence, 3. Male professional soccer and rugby players who underwent ACLR with an MCL injury, which was treated either operatively or nonoperatively, between 2015 and 2022 were each compared with 5 uninjured control players matched by age, sport, playing position, league, match appearances, and minutes played in the 12 months before injury. Kaplan-Meier survival analysis and Cox proportional hazards regression models were created. Overall, 90.4% (soccer, 92.6%; rugby, 87.5%) of players with ACLR+MCL injuries returned to play at 11.6 ± 4.1 months, which was similar to the 91.5% rate (soccer, 92.8%; rugby, 89.5%) of uninjured control players still competing at 11 months after the operation date of their matched player with injury.  At 2 years postsurgery 81.9% of all injured athletes were still competing compared to 81.3% in the control group. This decreased to 61.7% and 62.8%, respectively, at 5 years postsurgery. There was no difference between the still playing rates of the ACLR+MCL operative group 2 and 5 years postsurgery compared to their uninjured controls (2 years: 75.0% vs 75.9%; 5 years: 37.5% vs 41.5%) or between the ACLR+MCL nonoperative group and their uninjured controls (2 years: 86.2% vs 84.6%; 5 years: 70.5% vs 70.8%).  Age, sport, and competition level all had a significant effect on retirement risk, but being injured did not. After controlling for age, sport, and level played, the median career length was 7.07 years in the uninjured group compared to 6.68 years in the ACLR+MCL injury group. After ACLR with either operative or nonoperative management of an associated MCL injury, professional soccer and rugby players have high rates of RTP and maintain career longevity equal to that of a player without injury if the severity of the MCL injury is recognized and treated appropriately.
Zghal, F, Colson, SS, Bouzid, MA, Elloumi, M, Laurencelle, L, Behm, DG, Granacher, U, and Chaouachi, A. Effects of combined training on physical fitness according to maturity in male youth soccer players. J Strength Cond Res XX(X): 000-000, 2026-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.
Probiotic supplementation is attracting increasing attention among sports science and performance practitioners for its potential to support gut and immune function, adaptation to training, recovery and exercise performance. Purpose: To investigate the perceptions, as well as the current and common practices of practitioners supporting elite soccer teams regarding probiotic supplements. Sixty football practitioners from 5 different countries participated in a study consisting of a survey including 5 domains: demographic and professional characteristics (Who); perceptions about probiotics for health and performance (Why); methodological procedures about probiotics (What); mode of supplementation (How) and real-life practices about probiotics supplementation (When). Data revealed 5 main findings: (1) overall agreement on the importance of probiotics for soccer players (80.0%) and on the consumption under the practitioner's supervision (76.8%); (2) lack of consensus about the effects on athletic performance and recovery; (3) strong agreement on the use of probiotics to treat diarrhea (61.0%) and gastrointestinal symptoms (66.1%); (4) reported preference for multi-strain and multi-species probiotic supplements (85.2%); and (5) daily dosing frequency (one dose per day; 69.1%) and a preference for capsule formulations (83.3%). Probiotic use is highly prevalent among professional teams and is largely supervised by practitioners, with a strong emphasis on gut and immune health. However, despite this widespread adoption, there remains considerable uncertainty and limited consensus regarding optimal strains, dosing strategies, timing, and the potential effects on athletic performance, sleep and recovery. These findings highlight a clear practice-evidence gap, underscoring the need for high-quality, soccer-specific research and enhanced practitioner education for probiotic use in professional soccer.
Jiwan, NC, DeKuiper, KJ, Sysol, LA, Chabala, GE, and Costa, PA. Passive heating via heating pads improves vertical jump and agility performance in NCAA Division III soccer players. J Strength Cond Res XX(X): 000-000, 2026-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.
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.
Repeated-sprint training is an effective training strategy, yet the impact of manipulating rest intervals is equivocal. Using a parallel group, randomised trial, we explored the effects of two six-week, twice-weekly, time- and volume-matched repeated-sprint protocols with different passive rest intervals on fitness outcomes in male soccer players. Twenty-three semi-professional soccer players were randomly allocated to Group 1 (10 s within-set, 80 s between-set rest; n = 12) or Group 2 (20 s within-set, 40-54 s between-set rest; n = 11). Both groups continued their regular soccer, gym training, and matches with all activities monitored using differential ratings of perceived exertion (dRPE, centiMax® scale). Fitness outcomes were: 10 m, 20 m, 40 m sprint times, maximum velocity (VMax), countermovement jump (CMJ), and maximal aerobic speed (MAS). A linear mixed model and equivalence testing explored between-group differences in dRPE with analyses of covariance comparing between-group change differences in fitness. Repeated-sprint session intensity was 57.2 ± 6.9 AU with equivalence between groups for all activities. Between-group change differences in fitness were: 0.00 (95% Confidence Interval -0.05, 0.06) s, 0.03 (-0.05, 0.12) s, and 0.05 (-0.06, 0.16) s for 10 m, 20 m, and 40 m sprints, -0.09 (-0.36, 0.17) m.s-1 for VMax, -0.9 (-3.0, 1.2) cm for CMJ, and 0.05 (-0.09, 0.19) m.s-1 for MAS. These findings suggest little impact of our rest period manipulations on between-group training loads or fitness changes following a 6-week repeated-sprint intervention. Given the limited sample size, our results must be interpreted as preliminary, requiring further confirmation.
This randomized parallel-group study examined the effects of curvilinear sprint (CS) training with different radii on linear sprint (LS) performance, CS ability, change of direction (COD), and horizontal force-velocity (FV) profile in youth soccer players. Eighteen male youth soccer players from the same academy were randomly assigned to a narrow CS group (NCSG; 5.15 m radius) or a wide CS group (WSCG; 11.15 m radius). Both groups completed 12 CS sessions over 6 weeks (2 sessions/week), integrated into their regular team training. Pre- and post-intervention assessments included LS (5-30 m), CS tests on both the good and weak sides over two radii (7.15 m and 9.15 m), modified 505 COD test, and sprint mechanical variables from the FV profile (F0, V0, Pmax, RFmax, Drf). No significant time × group interactions were found for any variable (p > 0.05), indicating that narrow and wide CS training produced similar adaptations. However, within-group analyses revealed significant improvements (p ≤ 0.05) in most CS tests (except for the good side on 9.15 m), in 5 m and 20 m LS times and COD performance. Additionally, the NCSG and WCSG showed small to moderate significant enhancements (p ≤ 0.05) in Pmax and RFmax after the training intervention. In conclusion, 6 weeks of CS training improved LS, CS ability, COD performance, and key sprint mechanical outputs in youth soccer players. These findings suggest that CS training is a specific and effective method for enhancing multidirectional speed and sprint mechanics in this population.
Hamstring injuries are common in soccer, and fatigue-induced alterations in core function may influence neuromuscular control and hamstring performance. To investigate the acute effects of a core endurance fatigue protocol on isokinetic hamstring strength and active knee extension (AKE) range of motion in male soccer players. Thirty male soccer players participated in this pre-post experimental study. Their mean age was 25 ± 3.2 years, mean height was 179.4 ± 6.6 cm, mean weight was 74.1 ± 12.3 kg, and mean sports experience was 8.3 ± 2.1 years. Participants underwent pre- and post-fatigue assessments of concentric and eccentric hamstring peak torque, functional hamstring-to-quadriceps ratios, and AKE flexibility following a core endurance fatigue protocol. Following fatigue, eccentric hamstring strength and the functional hamstring-to-quadriceps ratio at 240°/s decreased significantly. The changes in the functional hamstring-to-quadriceps ratio at 60°/s and AKE flexibility were smaller and not consistently significant after adjustment. Core endurance fatigue is associated with acute neuromuscular changes in variables linked to hamstring function. These exploratory findings suggest that core endurance may be relevant in injury prevention, although prospective studies are needed to establish clinical relevance.
Ribeiro, N, Gonzalo-Skok, O, Loureiro, N, Ferreira, R, Araújo, JP, Bishop, C, and Tavares, F. Impact of two soccer seasons on the magnitude and direction of interlimb asymmetry in elite youth male players. J Strength Cond Res XX(X): 000-000, 2026-This study examined the influence of 2 competitive seasons on the magnitude and direction of interlimb asymmetry across countermovement jump (CMJ), change of direction (COD) speed, and isometric midthigh pull (IMTP) in elite male youth soccer players. A total of 60 academy players (U14-U17) were assessed at 6 time points across 2 seasons. Performance testing included unilateral CMJ, the 505 COD test, and unilateral IMTP. Biological maturation was estimated as the percentage of the predicted adult height. The magnitude of asymmetry was calculated using the standard percentage difference equation, and directional consistency was evaluated using Cohen's kappa coefficients. COD asymmetry displayed moderate-to-almost-perfect directional consistency between the first 2 time points (κ = 0.55-0.66), but the agreement declined to poor-to-fair levels across later assessments (κ = -0.15 to 0.32; TP3-TP6). By contrast, CMJ and IMTP demonstrated predominantly poor-to-slight directional agreement across all time points (κ = -0.33 to 0.40), indicating substantial instability in limb dominance. Throughout the longitudinal period, maturation did not meaningfully influence asymmetry magnitude in any performance measure. Interlimb asymmetry in elite youth soccer players is dynamic, task-specific, and largely independent of the task. COD asymmetry showed brief early season directional stability, whereas CMJ and IMTP asymmetry directions fluctuated considerably over time. These findings underscore the need for repeated task-specific monitoring and caution against overinterpreting small asymmetries or assuming maturational effects on interlimb differences.
Given the established merits and psychometric properties of the Athletic Fear Avoidance Questionnaire (AFAQ), the present study aimed to translate, cross-culturally adapt and validate the tool for use in a Swedish context. We included 95 amateur soccer players (male n = 31, female n = 64) from a convenience sample of eight soccer teams, who reported a sports injury within the past 12 months and were older than 15 years (mean 22, SD ± 6). They answered web-based surveys (SurveyMonkey©), including the AFAQ and the Tampa Scale for Kinesiophobia (TSK). Construct validity of the AFAQ was evaluated relative to the TSK, using Spearman's Rho. Reliability was assessed in a subset of participants (n = 53) with a test-retest evaluation of the individual items (KappaW) and the total score (Intra Class Correlation, ICC2.1). Internal consistency of the tool was assessed through Cronbach's Alpha (α). The cross-cultural translation and adaptation of the AFAQ was considered sound. The AFAQ-Swe showed a strong correlation with the TSK (r = 0.82), in line with the predefined hypothesis. The test-retest results demonstrated good-to-substantial reliability for the individual items (KappaW 0.52-0.82) and excellent reliability for the total score (ICC2.1= 0.80). The internal consistency was considered satisfactory (α = 0.85). The AFAQ-Swe demonstrates good measurement properties, with strong reliability and validity. The AFAQ-Swe is a concise, user-friendly tool that can be effectively utilised in the Swedish context, particularly among soccer players. However, further research is necessary to evaluate AFAQ's predictive validity for a safe return to sports.
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.
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.
Objective: 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. Methods: 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. Results: 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. Conclusion: 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.
Lyu, L, Wu, X-M, Li, Z, Qin, X-M, and He, Y. 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. J Strength Cond Res XX(X): 000-000, 2026-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.
This study examined the effects of different plyometric training configurations on mental well-being in post-pubertal highly trained male soccer players. Participants were assigned to bilateral (4 × 8; n = 10), high-volume unilateral (4 × 8; n = 10), or low-volume unilateral (4 × 4; n = 11) training groups. Pre-post assessments included cognitive anxiety, somatic anxiety, self-confidence, attention, and emotional competence. Baseline scores were similar across groups for most variables (p > 0.05), except total emotional competence, which was higher in the unilateral 4 × 4 group (F = 13.4, p < 0.001, η2 = 0.48). Significant main effects of time were observed for all variables (F ≥ 18.7, p ≤ 0.001, η2 ≥ 0.37). Cognitive anxiety decreased significantly in all groups (p < 0.05), while somatic anxiety decreased significantly only in the bilateral group (p < 0.05). Self-confidence increased significantly in the bilateral and unilateral 4 × 4 groups (p < 0.05). Attention showed a significant time × group interaction (F = 3.54, p = 0.042, η2 = 0.20), with the unilateral 4 × 4 group improving more than the unilateral 4 × 8 group. Emotional competence increased in all groups; however, the unilateral 4 × 4 group remained higher at both pre- and post-test, resulting in a significant group effect (F = 16.4, p < 0.001, η2 = 0.53). No significant differences were found between high- and low-volume unilateral training for the other outcomes. These results indicate that plyometric training enhances mental well-being in youth highly trained male soccer players, but neither increased volume nor unilateral specificity provides additional benefits. Bilateral training may be most effective for reducing cognitive anxiety, while low-volume unilateral training offers a time-efficient alternative.