Elite Male Youth Soccer Players Research Articles

Effects of the number of ball touches among elite youth players during small-sided soccer games.

This study investigates the effects of manipulating the number of ball touches (free play vs. two touches) on the physical and technical actions of elite male youth soccer players during 5v5 + 2 goalkeepers (GKs) small-sided games (SSGs). Players played in two different SSGs: 1) free play, where the number of touches per possession was not restricted; and 2) two touches, where players were limited to a maximum of two touches per ball possession. A total of 24 male elite youth soccer players (age: 14.79±0.71 years; body mass: 56.02±1.41 kg; body height: 164±2.12 cm) participated in the study. Players' physical metric and technical performance data were captured using a global positioning system and video camera, respectively. A paired-samples t-test or Wilcoxon Signed-Rank Test was employed to examine differences in players' technical performance variables depending on SSGs' ball-touch rules. The results show significantly more unsuccessful passes (t=-3.48; P=0.04; d=1.92) when players were limited to two touches than when there were no pass limits. The physical metrics indicate that total distance covered (Z=-2.90; P=0.001; d=0.07), meters per minute (Z=-3.44; P=0.001; d=0.11), low-speed running (Z=-2.25; P=0.02; d=0.04) and high acceleration (Z=-1.90; P=0.05; d=0.28) were significantly higher when touches were unlimited than when they were not. Soccer coaches should decide the number of touches per ball possession they allow depending on their tactical and/or physical objectives in training.

Reference Values of Specific Physical Performances of Elite Youth Male Soccer Players: Taking into Consideration the Maturity Status

Reference Values of Specific Physical Performances of Elite Youth Male Soccer Players: Taking into Consideration the Maturity Status

The Effect of Traditional Strength Training on Sprint and Jump Performance in 12- to 15-Year-Old Elite Soccer Players: A 12-Month Controlled Trial.

Skratek, J, Kadlubowski, B, and Keiner, M. The effect of traditional strength training on sprint and jump performance in 12- to 15-year-old elite soccer players: a 12-month controlled trial. J Strength Cond Res XX(X): 000-000, 2024-The aim of the study was to evaluate the effect of traditional strength training on maximum strength (1 repetition maximum in front squat [FS] and back squat [BS]), jump (squat and countermovement jump), and linear sprint (LS) performance (5, 10, and 30 m) in elite young soccer players. A 12-month longitudinal design was chosen, and 48 elite male youth soccer players (age: 12-15 years) were included. The subjects were divided in 2 groups (a strength training group [STG] and a control group [CG]). The intervention group trained for 1 year over a competitive soccer season with additional sessions to their regular soccer practice (4 sessions per week), while the CG did not complete any additional sessions to the regular soccer training (4 sessions per week). The additional strength training (2 sessions per week [each approximately 30 minutes]) consisted of either parallel FS or BS. The squat variants switched in each session. Data were analyzed using a 2 × 3 (group × time) repeated-measures analysis of variance. The main findings of this study were that the STG resulted in significant pretest and post-test improvements in maximum strength (d = 3.75-5.58), jump (d = 0.84-1.14), and LS performance (d = -0.25 to 0.44), while for the CG, smaller increases or performance decreases were measured (maximum strength: d = 1.64-2.7; jump: d = 0.12-0.31; sprint: d = 0.00-025). A significant interaction effect in all variables indicated significant (p < 0.05) stronger performance improvements compared with the CG. Traditional strength training in elite youth soccer players is recommended to increase strength and speed-strength (jump and sprint performance) and should be considered in long-term athletic development programs.

Mapping talent pathways: A comparative study of developmental activities and practice structure in Brazilian and Spanish U-18 elite youth male soccer players

The purpose of this study was threefold: (1) to compare the engagement in various types and amounts of soccer activities during childhood and adolescence between Brazilian and Spanish elite youth soccer players; (2) to test what talent development pathway characterizes youth development in elite soccer in Brazil and Spain and (3) to compare the practice structure between elite youth soccer in Brazil and Spain. Participants were 131 U-18 elite male soccer players from Brazil ( n = 68) and Spain ( n = 63) competing in the national league. The Participant History Questionnaire was used to measure the soccer activities undertaken by players. Developmental activities were analyzed for two age periods: childhood (6–12 y/o) and early adolescence (13–15 y/o). In Spain, players started their involvement in practice and competition in soccer earlier compared to Brazilian players ( p &lt; .05). Brazilian players were more involved in structured activities, such as practice in soccer and futsal, and participated in a greater number of sports in childhood and early adolescence ( p &lt; .05). We found a very similar percentual practice structure (individual, pair, drills, group tactics and collective tactics activities) between Spain and Brazil, although Brazilian players accumulated a greater practice volume. It is concluded that Spanish and Brazilian U-18 elite youth male soccer players were differentiated by their milestones in soccer and their engagement in practice activities during childhood and early adolescence. Talent development pathway of male soccer players in Spain was characterized by the early engagement pathway, while the Brazilian system was characterized by the specialized sampling model.

Influence of contextual factors on match running performance of starters and non-starters in elite youth male soccer players.

This study investigated the effects of match location, quality of opposition (classified into: strong [1st to 4th position]; intermediate [5th to 15th position]; weak [16th to 20th position]), and match outcome on the match running performance of starters and non-starters from a top elite Brazilian soccer team. Absolute measures were calculated using total distance, high-speed (19.8-25.2 km·h-1), sprinting (≥ 25.2 km·h-1), total distance high-acceleration (> 2m·s2), and deceleration (< -2m·s2) were recorded by GPS units from a sample of young soccer players (N = 25) in a total of 17 matches. Relative measures were calculated by dividing absolute measures by the total duration of the matches. Non-starters covered greater total distance (p = 0.02), sprinting (p = 0.02), high-acceleration and deceleration (p = 0.04), sprinting distance relative per minute played (p = 0.005), and high-acceleration and deceleration relative per minute played (p < 0.001) when the team plays at home, strong opponents, and wins the matches. Starters covered greater total distance in high-speed running (p = 0.04), high-acceleration and deceleration (p = 0.03), and high-speed running relative per minute played (p = 0.04) when the team plays strong opponents and wins the matches. These findings highlight the impact of contextual factors during matches on the locomotor performance of young soccer players.

The effect of long-term soccer training on left ventricular structure and function in elite male youth soccer players.

Cardiac adaptations in elite, male adolescent youth soccer players have been demonstrated in relation to training status. The time course of these adaptations and the delineation of the influence of volatile growth phases from the training effect on these adaptations remain unclear. Consequently, the aims of the study were to evaluate the impact of 3 years of elite-level soccer training on changes in left ventricular (LV) structure and function in a group of highly trained elite youth male soccer players (SP) as they transitioned through the pre-to-adolescent phase of their growth. Twenty-two male youth SP from the highest Level of English Premier League Academy U-12 teams were evaluated once a year for three soccer seasons as the players progressed from the U-12 to U-14 teams. Fifteen recreationally active control participants (CON) were also evaluated over the same 3-year period. Two-dimensional transthoracic echocardiography was used to quantify LV structure and function. After adjusting for the influence of growth and maturation, training-induced increases in Years 2 and 3 were noted for: LV end diastolic volume (LVEDV; p = 0.02) and LV end systolic volume (LVESV; p = 0.02) in the SP compared to CON. Training-induced decrements were noted for LV ejection fraction (LVEF; p = 0.006) and TDI-S' (p < 0.001). An increase in training volume (Years 2 and 3) were aligned with LV volumetric adaptations and decrements in systolic function in the SP that were independent from the influence of rapid somatic growth. Decrements in systolic function were suggestive of a functional reserve for exercise.

Agreement between Inter-Limb Asymmetries in Single and Triple Unilateral Hops, and Associations with Bilateral Jumping and Sprint Performance in U17 and U19 Soccer Players

The purpose of this study was to investigate the agreement regarding the direction of interlimb asymmetry (ILA) between different horizontal jumping tests, to examine the differences in ILA between different age categories and to assess the relationship between ILA and sprint and jump performance. The sample included 38 elite youth male soccer players from two distinct age categories (U17 and U19). The testing procedure consisted of a 10 m sprint test, unilateral and bilateral broad jumps, and unilateral and bilateral triple hops. The results showed moderate correlation and fair agreement in the direction of ILA between single broad jumps and single-leg triple hops (κ = 0.42; p = 0.014). The magnitude of ILAs tended to be larger in the unilateral triple hop (5.41 ± 5.25%) compared to the unilateral single hop (3.54 ± 2.67%). Furthermore, the older group had smaller ILA magnitudes in both jumping tests, with significant differences between age groups being observed only in single hops (p = 0.46; d = 0.78). Additionally, significant associations were found only between the ILA unilateral triple hop with bilateral single jump (r = −0.39) and sprint performance (r = 0.40), while ILA in the broad jump showed no significant associations with performance metrics. Based these results, the unilateral triple hop could be recommended as the preferred horizontal jump variation for screening soccer players. Furthermore, in line with the literature, mean ILA in horizontal jumps were far below the commonly used threshold of &gt;10–15% (mean ILA 3.5–6.5%), which suggests that the ILA threshold for horizontal jumps should be reconsidered.

Inconsistent Effect of Psychometric-Scale Familiarization on the Relationship Between Ratings of Perceived Exertion and External Load Measures in Elite Youth Soccer Players.

To examine the moderating effect of familiarization on the relationship between external load and ratings of perceived exertion (RPEs)in elite youth soccer players. Thirty-five elite male youth soccer players were monitored over a 31-week period. Players had no previous experience using the centiMax scale (arbitrary units[AU]). The final sample included familiarized (blackness test; n = 20) and nonfamiliarized players (n = 15) with the Borg centiMax scale. Players recorded a global RPE and differential RPEs (dRPE) for breathlessness (RPE-B) and leg-muscle exertion (RPE-L) 15 to 30minutes following training sessions and competitive matches. Separate multivariable-adjusted random-effects generalized additive models with restricted maximum likelihood quantified familiarization versus no-familiarization differences in actual perceived exertion score (in AU) by number of accelerations, decelerations, and high-speed running distance (in meters) as predictor variables, respectively. Players improved their blackness test score from 39% to 78%. For explorations by number of accelerations, familiarization effects were not practically relevant for the RPE and RPE-B variables. The width and sign of the effects for the RPE-L variable at 30 efforts of 10AU (95% CI, 4-16AU) suggested thatscores were lower for players who underwent familiarization versus players who did not. Familiarization effects were not practically relevant for any RPE variable irrespective of the number of deceleration efforts and high-speed running distance covered. Improved performance on the blackness test did not have a moderating effect on the relationship between proxy measures of external load and RPEs.

Between-day reliability of inertial measurement unit parameters during soccer-specific change of direction test

This study assessed the between-day reliability of change of direction (COD) biomechanics and speed in youth soccer players using inertial measurement units (IMUs) and high-speed video. A soccer-specific COD test including a 180° pivot turn was performed in both directions by 15 elite female (age: 15.3 ± 0.6 years; height 162.6 ± 5.5 cm; body mass: 56.7 ± 7.1 kg) and 22 elite male (age: 15.4 ± 0.5 years; height 169 ± 5.9 cm; body mass: 58.5 ± 8.5 kg) youth soccer players in two consecutive days. The reliability of the variables was quantified by using intra-class correlation coefficient (ICC) analysis with limits of agreement (LoA) and Bland–Altman plots. Based on the results, neither peak resultant acceleration (PRA) nor peak angular velocity (PAV) during final foot contact was sufficiently reliable for 180° pivot turn biomechanics (poor reliability, &lt; 0.5), but the reliability of players’ running time to turn and total time was between acceptable to good (0.9&gt;; &gt; 0.7). However, when analyzing females and males separately, the PRA and angular velocity ICC's for females had poor to acceptable reliability, when turning left, and were statistically different from males ( Z-score &gt; 1.96). Acceptable to good reliability with reasonable (max 15% difference) LoA implies that speed measures in different phases of COD could reliably reproduce individual differences in 180° pivot turn COD speed. Sex-related differences in repeatability of acceleration and angular velocity call for more comprehensive research in the future. PAV and PRA would not be recommended for the purpose of analyzing individual repeatability of specific steps of COD movement.

Curved sprinting in soccer: The influence of radius

The aims of this study were (i) to compare the sprint times between linear-sprint (LS) and curved-sprint (CS) tests of different radii, and (ii) to examine the relationships between sprint times in these tests in soccer players. Nineteen elite youth male soccer players (age, 18.6 ± 0.6 years) completed an LS test and three CS tests with different radii both from the left and the right side (11.15-m radius = CSwide, 9.15-m radius = CSmedium and 7.15-m radius = CSnarrow), each with a distance of 17 m. Differences in sprint times were examined using analysis of variance with Bonferroni-corrected pairwise comparisons and Cohen's d effect sizes (ES). Relationships between sprint times were determined by Pearson's product-moment correlations (r). Significantly lower sprint times were evident for LS compared to all three CS tests ( p &lt; .001, MD = 0.08–0.16 s, ES = 0.83–1.49), for CSwide compared to CSnarrow ( p = .02, MD = 0.04 s, ES = 0.47) and for CSmedium compared to CSnarrow ( p &lt; .001, MD = 0.07 s, ES = 0.82). Very large correlations ( p &lt; .001, r = 0.75–0.80) were found between sprint times in LS and the three CS tests. Very large to nearly perfect correlations ( p &lt; .001, r = 0.79–0.91) were found within the three CS tests. Practitioners should be aware that sprint times are lower in LS compared to CS of different radii and that CS times are higher at narrower angles compared to wider angles. Given the high correlations within three CS tests, the application of only one CS (e.g., CSmedium) during a test battery may be sufficient if using different CS is not possible. Results of the correlation analysis also suggest that LS contributes to CS performance, however, to slightly different extents depending on the radius of the CS. Consequently, both LS and CS drills might be incorporated into sprint training practices of elite youth soccer players.

Predictive modeling of lower extremity injury risk in male elite youth soccer players using least absolute shrinkage and selection operator regression.

To (1) identify neuromuscular and biomechanical injury risk factors in elite youth soccer players and (2) assess the predictive ability of a machine learning approach. Fifty-six elite male youth soccer players (age: 17.2 ± 1.1 years; height: 179 ± 8cm; mass: 70.4 ± 9.2kg) performed a 3D motion analysis, postural control testing, and strength testing. Non-contact lower extremities injuries were documented throughout 10months. A least absolute shrinkage and selection operator (LASSO) regression model was used to identify the most important injury predictors. Predictive performance of the LASSO model was determined in a leave-one-out (LOO) prediction competition. Twenty-three non-contact injuries were registered. The LASSO model identified concentric knee extensor peak torque, hip transversal plane moment in the single-leg drop landing task and center of pressure sway in the single-leg stance test as the three most important predictors for injury in that order. The LASSO model was able to predict injury outcomes with a likelihood of 58% and an area under the ROC curve of 0.63 (sensitivity=35%; specificity=79%). The three most important variables for predicting the injury outcome suggest the importance of neuromuscular and biomechanical performance measures in elite youth soccer. These preliminary results may have practical implications for future directions in injury risk screening and planning, as well as for the development of customized training programs to counteract intrinsic injury risk factors. However, the poor predictive performance of the final model confirms the challenge of predicting sports injuries, and the model must therefore be evaluated in larger samples.

Effect of a Four-Week Soccer Training Program Using Stressful Constraints on Team Resilience and Precompetitive Anxiety.

The present study examined the effects of stressful constraints during soccer trainings on psychological skill development and internal load when compared with control (nonstressful) trainings. A total of 51 elite male youth soccer players (27 in the experimental group, M = 16.54 years; 24 in the control group, M = 15.44 years) participated in the study. In a 12-week longitudinal survey, team resilience, using the Spanish version of the Characteristics of Resilience in Sports Teams Inventory, and anxiety, using the Sport Anxiety Scale, were measured at baseline (after 4 weeks of regular trainings), postprotocol (after 4 weeks of control or experimental trainings), and follow-up (after 4 weeks of regular trainings). Results show that, when compared with the control group, a program with stressful constraints helped young soccer players to develop better psychological skills: specifically, increased ability to cope with impairments in resilience (both resilience characteristics and team vulnerability under pressure; p < 0.001). Increases in anxiety (p = 0.06) and decreases in preoccupation (p < 0.001) and lack of concentration (p < 0.001) were also observed. The adaptation of human behavior to specific trainings may explain these results. In conclusion, the regular exposure of young soccer players to stressful situations during trainings shows benefits for their psychological skill development in soccer. Then, benefits on internal load were also observed.

Substitute running outputs in elite youth male soccer players: less peak but greater relative running outputs.

Coaches consider substitute players to be a substantial factor in influencing the outcome of a soccer match. Substitute players are expected to make physical impact on the match by superseding the running output of the player they replaced and are a key tool for managing in-game fatigue and influencing the outcome of a game. This study investigated the physical impact and internal response of substitute players, compared to starting and full-match players. We also sought to determine if differences between substitution statuses were influenced by playing position. Players wore 15-Hz global positioning system tracking devices across 29 competition matches and were categorised according to their substitution status (full-match, starters, substitutes) and playing position (external defender, midfield, external attacker and central attacker). Peak total (TD) and high-speed running (> 5.0 m/s) distance (HSRD) were calculated using 1-, 2- and 5-minute rolling epochs. Relative running demands were reported as TD and HSRD per minute of total playing time. Substitute players performed less peak TD and HSRD in 1-, 2- and 5-minute epochs, and reported lower RPE compared to starting and full-match players. In contrast, substitutes performed greater relative HSRD per minute than starting and full-match players (p < 0.001, |d| range = 0.35-1.34). In conclusion, substitute players may have a relative physical impact but do not replicate or supersede the peak demands of full-match players. Coaches and practitioners should implement targeted warm-up interventions to enhance substitute readiness to meet the peak running demands in order to have a more effective physical impact.

Maturity-Associated Differences in Match Running Performance in Elite Male Youth Soccer Players.

To investigate the influence of maturation on match running performance in elite male youth soccer players. A total of 37 elite male youth soccer participants from an English professional soccer academy from the U14s, U15s, and U16s age groups were assessed over the course of 1 competitive playing season (2018-2019). Relative biological maturity was assessed using percentage of predicted adult height. A global positioning system device was used between 2 and 30 (mean = 8 [5]) times on each outfield player. The position of each player in each game was defined as defender, midfielder, or attacker and spine or lateral. A total of 5 match-running metrics were collected total distance covered, high-speed running distance, very high-speed running distance, maximum speed attained, and number of accelerations. Relative biological maturity was positively associated with all global positioning system running metrics for U14s. The U15/16s showed variation in the associations among the global positioning system running metrics against maturity status. A multilevel model which allowed slopes to vary was the best model for all parameters for both age groups. In the U14 age group, advanced maturation was associated with greater high-speed running distance. However, maturation did not contribute toward variance in any of the indices of running performance in the U15/16s. In the U15/16 age group, significance was observed in the spine/lateral playing positions when undertaking actions that required covering distance at high speeds. Maturation appeared to have an impact on match-running metrics within the U14s cohort. However, within the U15/16s, the influence of maturation on match-running metrics appeared to have less of an impact.

Analysis of the most demanding passages of play in elite youth soccer: a comparison between congested and non-congested fixture schedules

ABSTRACT This study aimed to examine the most demanding passages of play in elite youth soccer for congested and non-congested fixture schedules. Seventeen elite youth male soccer players (18.2 ± 1.3 years old) participated in this study across 30 competitive matches. Assessed matches included congested (n = 12, three matches within eight consecutive days or less) and non-congested matches (n = 18, at least 5 days between matches). The players’ activity profiles during matches were analysed using global positioning measurement units (GPS). Players activity included: distance covered, distance covered at different velocities, high-intensity accelerations and decelerations, and player load. The most demanding passages (MDP) of match play was calculated using a moving average method within three-time windows (i.e., 1, 5, and 10 min). Data were analysed using a Bayesian ANOVA. During congested fixtures, the players’ distance covered and player load declined, with the former decreasing across all the MDP time windows, whereas the latter exclusively into the long-time windows (i.e., 5 and 10 min). Conversely, statistical differences in the remaining variables were anecdotal and in favour of the null hypothesis (i.e., Bayes factor <1), suggesting a non-influence of the competition fixture schedule. These findings provide insight into the MDP of youth soccer, helping practitioners to periodize training and recovery strategies during different competitive fixture schedules.

Accumulative Weekly External and Internal Load Relative to Match Load in Elite Male Youth Soccer Players.

The aim of this study was 2-fold: (1)to assess and compare the external and internal load of elite young soccer players during competitive microcycles and (2)to describe the training/match ratios (TMr) in elite male youth soccer players. Twenty-one youth soccer players were monitored using a 10-Hz global positioning system. Total distance covered, running distance (RD), high-speed RD, sprint distance, number of accelerations and decelerations, player load, and rated perceived exertion were recorded during training sessions and matches. The TMr was calculated for each load measure. All variables were also normalized dividing the load per minute of activity. The RD, high-speed running, and sprint distance were higher 3 days before the match and 2days before match compared with the rest of the training sessions. However, accelerations, decelerations, and player load were higher 4days before match than other sessions. Besides this, the TMr of RD, high-speed running, and sprint distance were associated with lower values than the TMr of total distance covered, accelerations, decelerations, and player load. The match constituted the highest load during competitive microcycle. The present data support the idea that youth soccer coaches and practitioners must consider relative training load according to match demands to better manage and evaluate player periodization.

Age-Related Changes in Landing Mechanics in Elite Male Youth Soccer Players: A Longitudinal Study

The aim of this longitudinal observational study was to examine the age differences in jump landing kinematics in 13–17-year-old male soccer players. Landing technique was evaluated in three consecutive seasons in U14 (n = 15) and the U16 (n = 10) competition age groups using the Landing Error Scoring System (LESS). For the LESS, ANOVA revealed no significant interaction effect (p = 0.81, η2 = 0.009) or main effect for groups (p = 0.15, η2 = 0.086), but a significant year effect was observed (p &lt; 0.001, η2 = 0.265). The LESS score in the U14 group decreased significantly in the second year (5.7 ± 1.9, p = 0.006, d = 0.84) and in the third year (5.9 ± 2.0, p = 0.020, d = 0.70) compared to the first year (7.1 ± 1.7). The LESS score in the U16 group decreased significantly in the second year (5.1 ± 0.9 points, p = 0.034, d = 0.77) and in the third year (4.9 ± 1.4, p = 0.013, d = 0.92) compared to the first year (6.4 ± 1.2). This trend was supported by the results of the separate assessment of the sagittal plane joint displacement. These findings support previous limited findings from cross-sectional studies, which point to improved landing mechanics during maturation. However, the LESS scores in both groups indicate that players who were around and/or post-peak height velocity during the observed periods may be considered “at-risk”, and suggest that preventive training programs should be introduced at earlier stages of players’ development.

Sex Differences in Pre-Season Anthropometric, Balance and Range-of-Motion Characteristics in Elite Youth Soccer Players.

In soccer, injury epidemiology differs between males and females. It is clinically useful to know whether there are between-sex differences in selected characteristics relevant to primary injury risk and injury prevention practices. The purpose of this study was to explore between-sex differences in anthropometric, balance, and range-of-motion characteristics in Spanish elite male and female youth soccer players. This was a pre-season cross-sectional study. Sixty-nine males (age 16.8 ± 0.9 yr; height 175.9 ± 6.8 cm; mass 67.9 ± 6.3 kg) and thirty-seven females (age 17.2 ± 1.7 yr; height 164.0 ± 6.3 cm; mass 59.0 ± 5.8 kg) participated. Anthropometrics (standing/sitting height, bodymass, right/left leg length) and right/left anterior reach test (ART), hip internal/external active range of motion, active knee extension (AKE), and weightbearing lunge test (WBLT) were measured. Between-sex differences were assessed with Bonferroni-corrected Mann–Whitney U tests and Cliff’s delta (d). Between-sex significant differences (p < 0.003, d ≥ 0.50) were observed for anthropometric data and for hip internal rotation. No between-sex significant differences were observed for ART/AKE/WBLT measures. Between-sex significant differences with large effect sizes were identified for anthropometric data and right/left hip internal rotation. The present study adds new data to the literature for young Spanish male and female soccer players. The present findings will help inform clinical reasoning processes and future injury prevention research for elite male and female youth soccer players.

How different are soccer training sessions based on small-sided games? A cluster analysis to explore perceived exertion and training load

Background: Soccer coaching staffs may have difficulties in classifying properly the load accomplished during training sessions and understanding how players rate the effort and the training load during the micro-cycles. Objective: The aims of this study were to investigate if the features and duration of training tasks can automatically classify the different weekly training sessions into different clusters, and to describe and compare the features and duration of training tasks, rating of perceived exertion and training load from the different training sessions across both classifications (prescribed by staff per day vs. automatically per cluster). Methods: Eighteen elite youth male soccer players reported their rating of perceived exertion 10 min after each practice during twelve micro-cycles. In each micro-cycle, differentiated management of the task characteristics for each training day was implemented. A Random Forest Clustering was used to automatically assign each training session to one cluster and allowed to create similar groups and contrast them with the sessions prescribed by the coaching staff. Results: Proper manipulation of different variables of small-sided games (number of players, relative playing area per player, game orientation, training regimen) can automatically differentiate training sessions. Youth soccer players can also perceive each training session differently (p &lt; .05). Conclusions: Using different formats of small-sided games in each training session may be interesting to modulate the player's perceived load during the micro-cycle. However, results should be interpreted with caution, due to representing a single team and coaching staff.

Do conditioning focused various-sided training games prepare elite youth male soccer players for the demands of competition?

Relative metrics (i.e. distance covered per minute of match time) are regularly used to quantify soccer player movement demands. However, limited literature is available concerning the peak player demands during training. This study aimed to compare the relative and peak demands of conditioning-focused various-sided training games (VSG) to competition matches in elite youth male soccer players according to playing position. Data from twenty-nine competition matches (national) and twenty-two VSGs (small, medium, and large) were collected for twenty-three elite under-17 soccer players using 15-Hz portable global positioning system tracking devices (GPSports, Canberra, Australia). Relative player movements were reported as total distance (TD) and high-speed running distance (HSRD) (> 5.0 m/s) per minute of total playing time. Peak player movements were calculated using a 1-minute rolling epoch length, reported as the maximum TD and HSRD. Linear mixed models demonstrated interactions between VSG type and player position for relative TD (p < 0.001) and HSRD (p < 0.001), and peak TD (p = 0.010) and HSRD (p = 0.003). The relative TD of VSGs were greater than match-play for all player positions. However, only Central Defenders demonstrated similar HSRD in MSGs and LSGs compared to match-play when analysed using relative calculations. External Attackers also replicated match-play relative HSRD demands in LSGs. No VSG type was found to replicate or supersede the peak player movements of match-play across any playing position. Consequently, VSGs should be supplemented with high-speed running training to prepare players for the peak running requirements of match-play.