Youth Soccer Players Research Articles

Profiling of Physical Qualities of Highly Trained Portuguese Youth Soccer Players

Background: A comprehensive understanding of variations in physical attributes both between and within young players is crucial for accurately identifying talent based on physical performance. This study aimed to compare maximum strength, jump, and sprint test results among young soccer players from different age categories and playing positions. Secondarily, this study aimed to analyze the association between maximum strength, jump, and sprint performances. Methods: A total of 103 players were categorized as U23, U19, U17, and U16. The players were placed into these age categories based on their football abilities. All participants completed standardized warm-ups, and testing procedures followed protocols established in previous studies. Results: Significant differences were found between age categories regarding the Isometric Mid-Thigh Pull (p < 0.001; η2p = 0.33), Countermovement Jump (CMJ) (p < 0.001; η2p = 0.50), Squat Jump (SJ) (p < 0.001; η2p = 0.29), and sprint (p < 0.001; n2p = 0.30) tests. No significant differences were detected in Broad Jump results between age categories. Moreover, no significant differences were observed in any physical capacities between playing positions. Furthermore, significant moderate-to-strong correlations (r = 0.30–0.86) were observed between all physical tests. Conclusions: Age categories can distinguish soccer players’ performance in different physical tests while no differences were observed between playing positions. Similar magnitude correlations were observed across all tests with only the CMJ and SJ being strongly correlated. Coaches and strength and conditioning professionals should apply a variety of tests to assess different physical qualities since they have different patterns between age categories.

Drop jump vertical kinetics identify male youth soccer players at greater risk of non-contact knee injury.

To determine associations between drop-jump vertical kinetics and acute non-contact knee injury-risk in male youth soccer players. Prospective cohort study. Professional soccer academies. Youth soccer players (n=264). Drop-jump vertical kinetics; injury epidemiology. Associations between kinetics and injury were assessed using binary logistic regression. Differences between injured and uninjured groups were compared using statistical parametric mapping. Peak braking: peak propulsive force ratio (OR=1.59, 1.10-2.29, p<0.05), propulsive work (OR=0.53, 0.28-0.99, p<0.05) and vertical stiffness (OR=1.68, 1.13-2.52, p<0.05) were associated with risk of sustaining a knee injury. All variables demonstrated 'unusable' or 'weak' levels of predictive ability in identifying players who would become injured (AUC 0.568-0.663). Drop-jump vertical kinetics that characterise the shape of the force-time waveform provide insight to acute non-contact knee injury-risk in male youth soccer players. Large transient spikes in force in the early phase of ground contact, coupled with reduced propulsive forces are a risk factor for acute non-contact knee injury in male youth soccer players. Variables are not sensitive enough to predict injury but provide additional training targets to help mitigate risk in this population.

Longitudinal Study of Mental Health in an Elite Soccer Club: Depression and Anxiety Symptoms Across a Competitive Season.

Longitudinal Study of Mental Health in an Elite Soccer Club: Depression and Anxiety Symptoms Across a Competitive Season.

Factors Influencing Change of Direction Performance in Youth Soccer Players: Velocity-Time Profile Analysis of the Pro-Agility Test.

Nakamura, H, Yamashita, D, Nishiumi, D, Nakaichi, N, and Hirose, N. Factors influencing change of direction performance in youth soccer players: velocity-time profile analysis of the Pro-Agility test. J Strength Cond Res XX(X): 000-000, 2025-The purpose of this study was to assess factors influencing change of direction (COD) deficit (CODD) and total time completion (CODTT) in adolescent soccer players through velocity-time profile analysis of the Pro-Agility Test. We enrolled 71 junior high school male soccer players and measured the 20-m sprint time and CODTT of the Pro-Agility Test, calculating CODD by subtracting the 20-m sprint time from CODTT. In addition, 3-dimensional motion data were collected using a markerless motion capture system during the Pro-Agility Test. Each section (5 m in the first, 10 m in the second, and 5 m in the third) was divided into acceleration and deceleration phases based on center of mass (COM) velocity, which were further divided into early and late halves. The mean COM acceleration during the acceleration phase (Acc) and deceleration during the deceleration phase (Dec) were calculated. Stepwise multiple regression analysis was performed to identify phases affecting CODTT and CODD. Statistical significance was set at p < 0.05. Total time completion of a COD task was explained by the second early Acc (β = -0.500), second late Dec (β = 0.433), and 20-m sprint time (β = 0.226) (adjusted R2 = 0.858), whereas CODD was explained by the second late Dec (β = 0.561) and second early Acc (β = -0.271) (adjusted R2 = 0.459). Maturity offset significantly correlated with CODTT (r = -0.456) but not with CODD (r = -0.119). The results indicated that deceleration and reacceleration during the Pro-Agility Test can be evaluated in adolescents by combining CODTT and CODD.

Using Age- and Size-Corrected Measures of Technical Skill to Better Assess the Performances of Youth Soccer Players

Using Age- and Size-Corrected Measures of Technical Skill to Better Assess the Performances of Youth Soccer Players

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

This study described the recovery responses following match play and examined the effects of manipulating training load 48h 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 (0.5h post, 48h post and 72h post) a match. At 48h 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 48h 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 72h 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 48h post-match. A high-volume and high-intensity session administered 48h post-match negatively influenced physical performance compared to a moderate training session.

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

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.

Effects of Neuromuscular Training Applied During Ramadan on Physical Fitness and Injury Prevention in Highly-Trained Male Youth Soccer Players

Abstract Background The intermittent fasting period of Ramadan is associated with reductions in training volumes and intensities to maintain physical fitness levels and reduce injury occurrence. Accordingly, it might be beneficial to include neuromuscular training (NMT) applied during Ramadan to avoid detraining and promote injury prevention in soccer players. This study aimed to analyze NMT effects on physical fitness and injury prevention during the Ramadan fasting period in young soccer players. Methods Forty young highly-trained male soccer players (U17/U19) were randomly assigned to a NMT (n = 20) or a traditional soccer-specific training group (TT, n = 20). NMT was conducted during Ramadan, lasted four weeks, and included two weekly sessions with exercises to promote muscle strength, power (plyometrics), speed, balance. TT contents were similar to the training period before Ramadan and comprised two weekly sessions including endurance and sprint-based exercises. The training volume was similar between groups. Body composition (body fat), linear sprint (5-m, 10-m, 30-m sprint), and change-of-direction (CoD) speed (T-test with and without ball), muscle power (squat [SJ], countermovement jump [CMJ]), peak isokinetic torque of the knee flexors, extensors, and soccer-specific performance (Loughborough soccer passing test [LSPT], Yoyo intermittent test level 1 [YYIRT L1], repeated-shuttle-sprint ability test [RSSA]) were determined before and after the Ramadan period. The overall injury rate per 1000 h of exposure (training, match) was carried out during and after the four-week Ramadan period and until the end of the soccer season (overall 8 weeks). Results No significant between group baseline differences were noted. Group-by-time interactions were significant for most assessed variables (0.001 &lt; p &lt; 0.004, 0.22 &lt; d &lt; 0.76) in favor of NMT. Variations in body mass, body fat, and BMI determined by post-hoc tests indicated significant decreases in NMT but not TT (0.026 &lt; p &lt; 0.047, 0.65 &lt; d &lt; 0.73). Moreover, post-hoc tests showed that NMT provided linear and COD speed improvements, enhanced muscle power (SJ, CMJ) and improved soccer-specific performance (p &lt; 0.001, 0.71 &lt; d &lt; 2.53). Additionally, post-hoc tests revealed significant isokinetic strength increases in favor of NMT for all peak torque variables (0.015 &lt; p &lt; 0.049, 0.64 &lt; d &lt; 0.81). The overall injury rate was significantly lower in NMT (8.00/1000 h exposure) compared to TT (13.33/1000 h exposure) (p = 0.049; d = 0.66). Conclusions Findings suggest that a four-week NMT conducted during Ramadan fasting helped to maintain or even improve measures of physical fitness including isokinetic strength. In addition, significant NMT-related reductions in injury occurrence were noted in highly-trained young male soccer players.

Comparative analysis of body composition in youth elite football players: Insights from professional academies

Background and Study Aim. Body composition plays an important role in determining athletic performance in soccer. Optimal levels of muscle mass and body fat percentage are key factors that influence speed, endurance, strength and overall physical readiness. Understanding and monitoring these parameters is crucial for player development, allowing coaches to design effective training programs tailored to their individual needs.Material and Methods. This study examined the body composition profiles of 66 football players from the academy of PFC Levski Sofia, categorized into four age groups: U15, U16, U17, and second team. Measurements were taken using the InBody 230 bioelectrical impedance analyzer, which assesses key metrics such as skeletal muscle mass, body fat percentage, BMI and fat-free mass. To identify significant age-related trends, advanced statistical methods were used, including descriptive analysis, ANOVA, and regression analysis.Results. The ANOVA results validated these findings, by showing statistically significant differences between age groups (F-statistic = 1199.91, p &lt; 0.05). These results confirmed that anthropometric indices, including weight, height, BMI, and body fat percentage, varied significantly across different age categories, highlighting the importance of customized training and nutrition strategies at each stage of development. The findings revealed a consistent increase in body weight, height and BMI with age, accompanied by a significant decrease in body fat percentage. These trends are in line with existing literature, which reinforces the importance of body composition monitoring as part of player development.Conclusions. This study underscores the importance of body composition monitoring in optimizing performance, preventing injury, and guiding individualized training programs for elite youth soccer players. Customized training and nutrition strategies are essential to ensure optimal physical development and long-term success in competitive soccer.

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

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.

The relationship between individualised speed thresholds and changes in aerobic fitness in elite professional youth soccer players. A case study

The relationship between individualised speed thresholds and changes in aerobic fitness in elite professional youth soccer players. A case study

Positional Differences in Internal and External Training Load Metrics in Elite Football Academy League Players

This study aims to provide guidance for evidence-based training optimization by examining differences in position-specific internal and external training loads of elite youth soccer players. A total of 27 players from a U17 team competing in the Elite Academy League participated in the study, comprising four fullbacks, four forwards, eight wingers, seven midfielders, and four center-backs. The mean age of the players was 17 years, the mean height was 179.19 ± 6.05 cm, and the mean body weight was 71.62 ± 6.38 kg. Data were collected during the competition period. Internal training load was assessed using heart rate (minimum, average, and maximum) and Rating of Perceived Exertion (RPE). External load parameters included measures such as total distance, number of sprints, accelerations and decelerations, and time spent in Speed Zone 4 (21.0-23.99 km/h) and Speed Zone 5 (24.0 &gt; km/h). The statistical analysis using the Kruskal-Wallis test determined the significance level as p ≤ 0.05. As a result of the study, significant differences were found among the values of Sprint (p &lt; 0.001), Speed Zone 5 (p &lt; 0.001), Acceleration (p &lt; 0.001), Deceleration (p = 0.029), Training Load (p &lt; 0.001) and Maximum Heart Rate (p &lt; 0.001) according to positions. These findings emphasize the specific physical and physiological requirements of each position. Therefore, coaches and sports scientists must develop position-specific training programs considering these requirements. Such an approach can help athletes improve their performance, reduce the risk of injury, and ensure an effective recovery process. Tailoring training protocols to positional demands can enhance player performance, reduce injury risk, and optimize recovery strategies in elite youth football.

Career patterns within men’s and women’s soccer talent systems: the typical pathway to the top is atypical

ABSTRACT Talent systems in soccer aim to identify and recruit the most promising players, ideally during early childhood. Compared to non-recruited players, recruited players are typically provided with higher-quality coaching and training facilities, which are assumed to accelerate their skill development. As a result, future elite players are expected to emerge from this group of early recruits in a singular, uninterrupted progression. While recent research increasingly challenges this assumption, how youth players develop within soccer talent systems remains largely unknown. Therefore, this study aimed to examine whether early recruitment correlates with senior performance levels and, as a next step, to quantitatively explore the shape of nearly 3,000 Dutch male and female youth soccer players’ career patterns. Results showed that roughly 8% and 10% of all recruited players attained senior elite soccer. In addition, we found a weak relationship between academy recruitment age and the attainment of elite soccer status. More importantly, using Guttman errors to quantify the typicality of career patterns, we discovered that career interruptions were positively related to attaining senior elite soccer status. Specifically, senior international players exhibited diverse and interrupted career patterns. We therefore conclude that the typical pathway to future soccer success can be characterised as atypical.

The Acute Effects of 25- Versus 60-Minute Naps on Agility and Vertical Jump Performance in Elite Youth Soccer Players: The Role of Individual Chronotype.

While napping is recognized as an effective strategy for mitigating insufficient sleep and enhancing athletic recovery, limited research exists on its effects on football players' anaerobic performance, particularly concerning chronotype variations. This study investigated the impact of strategic napping durations on anaerobic performance and agility in football players under the age of 19 (U19), considering individual chronotypes and psychological factors. Sixteen young football players (age: 17.18 ± 1.04 years) participated in this crossover randomized controlled study. Participants underwent three conditions: no nap (NoN), 25 min nap (N25), and 60 min nap (N60), with 48 h washout periods between sessions. Performance was assessed using the Countermovement Jump Test (CMJ), Illinois Agility Test, and Illinois Change-of-Direction Test with Ball. Chronotype assessment, sleep quality, and mood states were evaluated using the Morningness-Eveningness Questionnaire, Pittsburgh Sleep Quality Index, and Profile of Mood States Questionnaire, respectively. The 60 min nap protocol demonstrated significant improvements in agility performance compared to other conditions, particularly in the Illinois Agility Test and Change-of-Direction Test with Ball. However, no significant differences were observed in CMJ parameters across napping conditions. Chronotype variations showed correlations with agility performance and psychological factors, with evening-type participants displaying different responses to napping interventions compared to morning-type participants. While a 60 min post-lunch nap did not affect anaerobic performance, it positively influenced agility performance in soccer players. Chronotypic differences significantly impacted both agility performance and associated psychological factors. These findings suggest that integrating napping strategies into athletic training programs, while considering individual chronotypic variations, may present opportunities for enhancing specific aspects of athletic performance. Further research is needed to elucidate the underlying physiological, psychological, and cognitive mechanisms of these effects.

Prescribing playing intensity in small-sided games using rating of perceived effort among youth soccer players: a randomized crossover trial

ABSTRACT In this study, we examined whether the 0–10 rating of perceived effort (RPE) scale can serve as a method for prescribing playing intensity in small-sided games (SSGs). We conducted a randomized crossover trial involving 25 young male football players (age range 16–18 years). Participants completed a familiarization and three experimental sessions where game intensity was regulated using prescribed intensities equal to RPE of 6, 8, or 10. Each session involved six teams of three players playing in three SSGs, with 4 min of rest, in a playing area of 133 square meters per player. Outcomes included total distance, high-speed running distance (HSRD), intense acceleration and deceleration (IAD) counts, and average heart rate (HR). We fitted mixed models and estimated 95% confidence intervals (CIs) to analyze the results. The CIs for all locomotive outcomes indicated an increase at RPE-8 and RPE-10 compared to RPE-6. Notably, the effects on HSRD and IAD were substantial, with differences between RPE-10 and 8 to RPE-6 ranging from 28% to 97%. Conversely, differences in the total distance the players covered per game between RPE-10 and 8 to 6 were minor (~5%). We could not identify clear differences between RPE-10 and 8 in the locomotive outcomes (differences range 0%–9.6%, CIs containing zero) nor in HR across all RPE conditions (differences range 1–3.5 bpm, CIs containing zero). We conclude that RPE can serve as a practical tool to prescribe medium or high intensity during SSGs, although its ability to differentiate between higher intensity levels or influence heart rate is limited.

The Use of the FIFA 11+ For Kids as an Injury Prevention Program in Youth Soccer Players: A Critically Appraised Topic

The FIFA 11+ For Kids was developed as an injury prevention program for youth soccer athletes between 7 and 13 years of age. Since its development, it has been introduced to youth soccer players worldwide, however, a critical summary of high-level randomized control trials to assist clinicians in determining how to effectively implement the program for injury prevention is lacking in the current literature. This critically appraised topic sought to determine the best practice recommendations for the implementation of the FIFA 11+ For Kids program to effectively prevent injuries in youth soccer players. A search of the literature was completed in December of 2023 using the terms “FIFA 11 for kids” and “randomized control trials” and “injury prevention.” Studies were included if they scored higher than 6/10 on the Physiotherapy Evidence Database Scale. A critical appraisal of high-level randomized control trials found that clinicians can use the FIFA 11+ For Kids as an effective injury prevention program for youth soccer players when factors including the frequency of application, the time needed to complete the program, compliance with the program, and training of team personal who lead the program are considered.

No match, more sleep: Greater weekend catch-up sleep in youth soccer players on free weekends.

No match, more sleep: Greater weekend catch-up sleep in youth soccer players on free weekends.

Effects of Intermittent Versus Continuous Small-Sided Games on Athletic Performance in Male Youth Soccer Players: A Pilot Study.

Adjusting the design of small-sided games and selecting the appropriate format can significantly enhance training outcomes and player development in soccer. The aim of the study was to compare the effects of intermittent small-sided games (ISSG) and continuous small-sided games (CSSG) on athletic performance metrics in male soccer players. This pilot study was conducted using a parallel group pre-test and post-test design, with 16 male youth soccer players randomly assigned to two groups: the ISSG group (n = 8, Mean age = 16.50 ± 0.53 years) and the CSSG group (n = 8, Mean age = 16.63 ± 0.52 years), ensuring a balance in pre-test performance and playing positions. The ISSG protocol began with 4 min sets in week one, progressively increasing to 7 min by week four, with 2 min rest intervals. The CSSG protocol involved continuous play, starting at 16 min and progressing to 28 min over the same period. Players underwent pre- and post-tests, with a 4-week training period. Performance metrics assessed included body composition, a 30 m sprint test, agility, horizontal jump, aerobic and anaerobic capacity, and static balance. Training intensity was monitored using the CR-10 Borg Rating of Perceived Exertion scale throughout the training period. Both groups exhibited improvements in horizontal jump, agility, aerobic and anaerobic power, and static balance, with no significant between-group differences. Sprint performance did not significantly improve in either group. The CSSG group reported higher RPE values and experienced a reduction in body mass index. Our findings demonstrate that both ISSG and CSSG resulted in similar improvements in athletic performance metrics in male youth soccer players. Coaches and practitioners can choose the most appropriate training method based on specific objectives, session duration, and player fatigue levels, thereby optimizing training outcomes.

Alternative training methods in soccer

Abstract The increasing level of physical fitness among soccer players necessitates the exploration of alternative training methods to enhance overall performance. Perceptual–cognitive skills are crucial for sport-specific capabilities such as decision making and reactive agility, enabling athletes to extract visual information from foveal, parafoveal, and peripheral vision. This study focuses on optimizing the utilization of peripheral vision in sports, addressing the demand for specialized training techniques and investigating additional avenues for practicing soccer-specific skills. This study assessed the impact of a 6-week intervention on the perceptual–cognitive performance of elite youth soccer players by examining peripheral perception, response time, and task-switching during soccer-specific motion execution. Outcomes were measured through a reactive agility test, a simulated decision-making task, and a maximal sprinting speed test. Using a pre–post design, 22 healthy male participants were divided into an experimental group and an active control group. The experimental group engaged in sport-specific tasks designed to enhance their perceptual–cognitive skills. Results revealed that the experimental group demonstrated significant improvements in reaction time during both the reactive agility test with and without a ball, an increase in the number of correct decisions in the simulated decision-making task, and a noteworthy enhancement in maximum sprinting speed, while handling a ball compared to the control group. While further research is needed to translate these findings into practical field settings, this study indicates that soccer-specific demands, extending beyond physical aspects, can be effectively targeted and improved.

A Combined 7-Week Strength and Power Training: Effects on Body Composition, Strength, Speed, and Agility in U14 and U16 Youth Elite Soccer Players

The aim of this study was to analyze the effects of a 7-week combined strength and power training program on body composition, aerobic capacity, strength, sprint, and agility in elite youth soccer players. Twenty-one players, divided into age groups (U14 and U16), participated in this study. In addition to four training sessions per week (plus matches), the two groups completed a strength training session on Match Day 4 (MD-4) and a power training session on Match Day 2 (MD-2). Before and after the intervention, various tests were conducted, including skinfold measurements, submaximal intermittent shuttle run, eccentric hamstring strength (EHS), countermovement jump (CMJ), single-leg jump (SLJ), sprint test with split times at 10 and 30 m, agility t-test, push-ups, and pull-ups. Our results indicate that a seven-week program of combined strength training led to significant improvements in body composition, EHS, jump performance, and pull-up tests for both groups of players (p &lt; 0.05). Moreover, the U14 group also demonstrated an improvement in the agility test (p &lt; 0.01). The U14 group experienced more substantial gains than the U16 group in agility and push-up performance (p &lt; 0.05). The sprint performance remained unchanged for both groups (p &gt; 0.05), suggesting that specific training is required to improve this quality.