Characteristics of high-level youth soccer players: variation by playing position

Relationship between body composition and physical capacities in junior soccer players

Abstract The number of studies related to soccer has been growing exponentially in the last years because the modality is considered the most popular in the world. It is known that the development of some specific physical capacities, even in young individuals, is essential to high-level performance and these capacities might be related to anthropometrics variables. The purpose of this study was to verify the relationship between body composition and physical capacities in young soccer players. Study participants were athletes from junior categories (under-12 and under-13) belonging to the Soccer Association of Chapecó, Brazil.. Athletes were submitted to agility, (Illinois), vertical jump (Sargent Jump), aerobic condition (TCAR), flexibility and sit-and-reach (Wells Bench) tests, as well as anthropometric assessment. All procedures were performed at UNOESC campus, Chapecó. Statistical analysis consisted of the Spearman’s Rô test, measuring the correlation among variables, additionally, significance level of p<0.05 was adopted. Results showed significantly correlation in agility (p=0.000; ρ=0.530) and vertical jump tests (p=0.003; ρ=-0.437) with body fat percentage. It was concluded that there is relationship between body fat percentage and agility and explosive power of lower limbs.

Field-Based Tests for the Assessment of Physical Fitness in Children and Adolescents Practicing Sport: A Systematic Review within the ESA Program

High levels of physical fitness (PF) can positively affect both health and cognitive function, thus monitoring its levels in youth can help increase health and quality of life in adult populations later on. This systematic review aims to identify PF field-based tests used in young European populations practicing sport to find tools that are adequate for the considered target involving a new battery within the Enriched Sport Activities (ESA) project. The Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement was followed. In the 83 identified articles, the main tests used were: vertical/horizontal jumps (for muscular strength/power); push-ups, running at maximum effort, sit-ups (for muscular strength/endurance); multistage non-intermittent and intermittent tests (for aerobic endurance); sit and reach (for flexibility); sprinting and agility T-tests (for speed and agility, respectively); 10 × 5 m shuttle run (SR) (for both speed and agility). Few studies assessed coordination, reaction time, power, and balance. Although the selected tests are widely used and validated, they do not determine all PF aspects and do not reflect sport-specific features. A final decision was made for the inclusion of the following tests: standing broad jump, seated medicine ball throw, 20 m SR test, 30 m sprint, Illinois test, and a new test, i.e., the crunning test, to assess different skill-related components at once. The use of this combination of tests allows for the assessment of all PF components and can help planning effective training programs and cultivate sporting talent.

Interactive Improvements of Visual and Auditory Function for Enhancing Performance in Youth Soccer Players

We analyzed the effects of a regular training program on the health- and skill-related physical fitness (PF) of talented soccer players aged < 12 years; visual reaction time (VRT) and auditory reaction time (ART) were also assessed. In this single-group interventional study, 78 talented male youth soccer players (mean age, 9.54 years) were critically selected by the Korean Educational Development Institute and underwent a 22-week training program consisting of 16 weeks of PF and basic skill training (90 min/week) and 6 weeks of intensive training (3, 150-min sessions/week). We assessed the pre- and post-training body composition, cardiovascular endurance, muscle strength and endurance, and flexibility. We also measured power, agility, coordination and speed, passing ability, VRT, and ART. All variables improved after training. Post-training VRT correlated with ART, muscle mass, power, cardiovascular endurance, 10-m dribble time, 10-m ball touch count, and 10-m successful pass count. ART only correlated with muscle mass. ART and 10-m ball-touch count influenced VRT, and VRT influenced ART. In conclusion, the training program enhanced the PF and visual- and auditory-related reactions in talented youth soccer players. This study suggests the importance of the assessed relationships, indicating that a training program that improves these parameters enhances the players’ performance.

The use of the Körperkoordinationstest für Kinder in the talent pathway in youth athletes: A systematic review

OBJECTIVES

Identifying talented athletes from an early age to accelerate their development requires the investment of substantial resources. Due to the need for multifactorial approaches to talent identification, motor competence assessments are increasingly prevalent in contemporary testing batteries. Therefore, the aim of this review was to evaluate the literature on the use of a product-oriented motor competence assessment tool, the Körperkoordinationstest für Kinder (KTK) in the talent pathway and determine whether it is warranted in such programs.

METHODS

Three electronic databases (i.e. PubMed, SPORTDiscus and Web of Science) were searched for studies that used at least one component of the KTK to assess motor competence for talent detection, identification, development and selection in athletic populations. A total of 21 articles were included in the review, of which seven used the full version of the KTK and 14 used modified versions or individual components of the battery. The quality of included studies was assessed using a modified version of the Joanna Brigg's Institute Critical Appraisal Checklist.

RESULTS

The analysed literature suggests that the KTK can successfully distinguish between athletes of different competition levels and across different sporting domains, however, findings should be interpreted with caution due to the cross-sectional nature of the studies. Furthermore, the moving sideways subtest displayed the greatest discriminative power for athletes of different competition levels. Motor competence was not affected by maturation and did not differ between genders or playing positions.

CONCLUSIONS

Collectively, these findings suggest that the KTK is a useful motor competence assessment in the talent pathway.

Match-Play and Performance Test Responses of Soccer Goalkeepers: A Review of Current Literature

Goalkeepers are typically the last defensive line for soccer teams aiming to minimise goals being conceded, with match rules permitting ball handling within a specific area. Goalkeepers are also involved in initiating some offensive plays, and typically remain in close proximity to the goal line while covering ~ 50% of the match distances of outfield players; hence, the competitive and training demands of goalkeepers are unique to their specialised position. Indeed, isolated performance tests differentiate goalkeepers from outfield players in multiple variables. With a view to informing future research, this review summarised currently available literature reporting goalkeeper responses to: (1) match play (movement and skilled/technical demands) and (2) isolated performance assessments (strength, power, speed, aerobic capacity, joint range of motion). Literature searching and screening processes yielded 26 eligible records and highlighted that goalkeepers covered ~ 4-6 km on match day whilst spending ~ 98% of time at low-movement intensities. The most decisive moments are the 2-10 saves·match^-1 performed, which often involve explosive actions (e.g. dives, jumps). Whilst no between-half performance decrements have been observed in professional goalkeepers, possible transient changes over shorter match epochs remain unclear. Isolated performance tests confirm divergent profiles between goalkeepers and outfield players (i.e. superior jump performance, reduced [Formula: see text]_2max values, slower sprint times), and the training of soccer goalkeepers is typically completed separately from outfield positions with a focus primarily on technical or explosive drills performed within confined spaces. Additional work is needed to examine the physiological responses to goalkeeper-specific training and match activities to determine the efficacy of current preparatory strategies.

Reliability and validity of field-based fitness tests in youth soccer players

This study aimed to establish between-day reliability and validity of commonly used field-based fitness tests in youth soccer players of varied age and playing standards, and to discriminate between players without ("unidentified") or with ("identified") a direct route to professional football through their existing club pathway. Three-hundred-and-seventy-three Scottish youth soccer players (U11-U17) from three different playing standards (amateur, development, performance) completed a battery of commonly used generic field-based fitness tests (grip dynamometry, standing broad jump, countermovement vertical jump, 505 (505COD) and T-Drill (T-Test) change of direction and 10/20 m sprint tests) on two separate occasions within 7-14 days. The majority of field-based fitness tests selected within this study proved to be reliable measures of physical performance (ICC = 0.83-0.97; p < .01). However, COD tests showed weaker reliability in younger participants (ICC = 0.57-0.79; p < .01). The field-based fitness testing battery significantly discriminated between the unidentified and identified players; χ² (7) = 101.646, p < .001, with 70.2% of players being correctly classified. We have shown field-based fitness tests to be reliable measures of physical performance in youth soccer players. However, results from the 505COD and T-Test change of direction tests may be more variable in younger players, potentially due to complex demands of these tests and the limited training age established by these players. While the testing battery selected in this study was able to discriminate between unidentified and identified players, findings were inconsistent when attempting to differentiate between individual playing standards within the "identified" player group (development vs. performance).

Talent Identification and Development in Male Football: A Systematic Review

BACKGROUND

Expertise has been extensively studied in several sports over recent years. The specificities of how excellence is achieved in Association Football, a sport practiced worldwide, are being repeatedly investigated by many researchers through a variety of approaches and scientific disciplines.

OBJECTIVE

The aim of this review was to identify and synthesise the most significant literature addressing talent identification and development in football. We identified the most frequently researched topics and characterised their methodologies.

METHODS

A systematic review of Web of Science™ Core Collection and Scopus databases was performed according to PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-analyses) guidelines. The following keywords were used: "football" and "soccer". Each word was associated with the terms "talent", "expert*", "elite", "elite athlete", "identification", "career transition" or "career progression". The selection was for the original articles in English containing relevant data about talent development/identification on male footballers.

RESULTS

The search returned 2944 records. After screening against set criteria, a total of 70 manuscripts were fully reviewed. The quality of the evidence reviewed was generally excellent. The most common topics of analysis were (1) task constraints: (a) specificity and volume of practice; (2) performers' constraints: (a) psychological factors; (b) technical and tactical skills; (c) anthropometric and physiological factors; (3) environmental constraints: (a) relative age effect; (b) socio-cultural influences; and (4) multidimensional analysis. Results indicate that the most successful players present technical, tactical, anthropometric, physiological and psychological advantages that change non-linearly with age, maturational status and playing positions. These findings should be carefully considered by those involved in the identification and development of football players.

CONCLUSION

This review highlights the need for coaches and scouts to consider the players' technical and tactical skills combined with their anthropometric and physiological characteristics scaled to age. Moreover, research addressing the psychological and environmental aspects that influence talent identification and development in football is currently lacking. The limitations detected in the reviewed studies suggest that future research should include the best performers and adopt a longitudinal and multidimensional perspective.

Physical Fitness Performance of Young Professional Soccer Players Does Not Change During Several Training Seasons in a Spanish Elite Reserve Team: Club Study, 1996-2013

Los Arcos, A and Martins, J. Physical fitness performance of young professional soccer players does not change during several training seasons in a Spanish elite reserve team: club study, 1996-2013. J Strength Cond Res 32(9): 2577-2583, 2018-The purpose of this study was to assess the changes in physical fitness performance in young professional soccer players during several training seasons in a Spanish elite reserve team. Physical test values (i.e., vertical jump test, straight line sprint test, and discontinuous and progressive submaximal running test) of 97 young professional soccer players who belonged for at least 2 consecutive seasons to the reserve team of a Spanish professional team from 1996 to 2013 were analyzed. A distinction was made between the soccer players who were promoted to the Spanish first/second divisions (n = 38) and those who were not (n = 59) (until the end of the 2016/2017 season). Players were also classified according to their playing positions. Independently of the competitive level reached and the playing position, the variability of the fitness performance was limited (coefficient of variation <6%) and the players did not improve their fitness values (effect size ≤ small) from the first to the last season in which they were enrolled in the team (after 2-4 seasons). During the last stage of training in an elite soccer academy, young professional soccer players achieve a very similar physical fitness performance when their soccer competence is evaluated, and other soccer performance factors are those which make them stand out for selection.

Relationship Between Tactical Performance, Somatic Maturity and Functional Capabilities in Young Soccer Players

The aim of the study was to investigate the relationship between tactical performance, somatic maturity, and functional capabilities in young soccer players. Study participants were 48 soccer players (14.80 ± 1.5 years) belonging to an extension project at the State University of Maringa - Brazil. Anthropometric measurements of body mass, body height, and sitting height were carried out. The number of years to peak height velocity (PHV) was used as an index of maturation. Evaluations of functional fitness included the following tests: sit-and-reach, Yo-Yo Intermittent Recovery Test Level 1, handgrip test, modified abdominal test, and vertical jumps (Counter Movement Jump and Jump Squat). Tactical performance was assessed through the System of Tactical Assessment in Soccer (FUT-SAT). Multiple Linear Regression models were used to estimate the relative contributions of functional and maturational capacities to tactical performance. The results indicated weak associations between the tactical performance indices and somatic maturity, functional capacity, and anthropometric attributes (r < 0.40). The Yo-Yo Test contributed to 36% of the defensive tactic performance variation in the under 13 category. These results suggest that the level of maturity, growth status, and functional fitness have limited impact on tactical performance of young soccer players.

The Yo-Yo Intermittent Tests: A Systematic Review and Structured Compendium of Test Results

Background: Although Yo-Yo intermittent tests are frequently used in a variety of sports and research studies to determine physical fitness, no structured reference exists for comparison and rating of test results. This systematic review of the most common Yo-Yo tests aimed to provide reference values for test results by statistical aggregation of published data.

Methods: A systematic literature search for articles published until August 2017 was performed in MEDLINE, Web of Science, SPORTDiscus and Google Scholar. Original reports on healthy females and males ≥16 years were eligible for the analysis. Sub-maximal test versions and the Yo-Yo Intermittent Recovery Level 1 Children's test (YYIR1C) were not included.

Results: 248 studies with 9,440 participants were included in the structured analysis. The Yo-Yo test types most frequently used were the Yo-Yo Intermittent Recovery Level 1 (YYIR1, 57.7%), the Yo-Yo Intermittent Recovery Level 2 (YYIR2, 28.0%), the Yo-Yo Intermittent Endurance Level 2 (YYIE2, 11.4%), and the Yo-Yo Intermittent Endurance Level 1 (YYIE1, 2.9%) test. For each separate test, reference values (global means and percentiles) for sports at different levels and both genders were calculated.

Conclusions: Our analysis provides evidence that Yo-Yo intermittent tests reference values differ with respect to the type and level of sport performed.The presented results may be used by practitioners, trainers and athletes to rate Yo-Yo intermittent test performance levels and monitor training effects.

Importance of Reactive Agility and Change of Direction Speed in Differentiating Performance Levels in Junior Soccer Players: Reliability and Validity of Newly Developed Soccer-Specific Tests

Agility is a significant determinant of success in soccer; however, studies have rarely presented and evaluated soccer-specific tests of reactive agility (S_RAG) and non-reactive agility (change of direction speed – S_CODS) or their applicability in this sport. The aim of this study was to define the reliability and validity of newly developed tests of the S_RAG and S_CODS to discriminate between the performance levels of junior soccer players. The study consisted of 20 players who were involved at the highest national competitive rank (all males; age: 17.0 ± 0.9 years), divided into three playing positions (defenders, midfielders, and forwards) and two performance levels (U17 and U19). Variables included body mass (BM), body height, body fat percentage, 20-m sprint, squat jump, countermovement jump, reactive-strength-index, unilateral jump, 1RM-back-squat, S_CODS, and three protocols of S_RAG. The reliabilities of the S_RAG and S_CODS were appropriate to high (ICC: 0.70 to 0.92), with the strongest reliability evidenced for the S_CODS. The S_CODS and S_RAG shared 25–40% of the common variance. Playing positions significantly differed in BM (large effect-size differences [ES]; midfielders were lightest) and 1RM-back-squat (large ES; lowest results in midfielders). The performance levels significantly differed in age and experience in soccer; U19 achieved better results in the S_CODS (t-test: 3.61, p < 0.05, large ES) and two S_RAG protocols (t-test: 2.14 and 2.41, p < 0.05, moderate ES). Newly developed tests of soccer-specific agility are applicable to differentiate U17 and U19 players. Coaches who work with young soccer athletes should be informed that the development of soccer-specific CODS and RAG in this age is mostly dependent on training of the specific motor proficiency.

A multidimensional approach to talent identification and selection in high-level youth Australian Football players

There is limited research in talent identification in youth Australian Football (AF), especially the factors that underpin selection into higher-level development programs. Therefore, this study explored age-related differences in high-level youth AF players and investigated characteristics influencing selection into a high-level development program. Anthropometry (stature, sitting height, body mass), maturity (estimated age at peak height velocity), motor competence (Körperkoordinationstest für Kinder), fitness (change of direction speed, lower body power and upper body muscular endurance) and coach skill ratings (kicking, marking and handballing) of 277 state academy players (U13-U15) were assessed. MANOVAs identified significant age-related differences for anthropometry, fitness, and coach skill ratings. Furthermore, 90.9 and 90.0% of U15 selected and deselected players were classified correctly. Selected players were more mature, taller, heavier, more explosive, faster at changing directions, and had superior kick technique and marking results. These results demonstrate considerable age-group performance outcome differences, highlighting that high-level academies should aim to select or deselect after 15 years of age. Additionally, it appears earlier maturing players are favoured for selection into a high-level academy. While practitioners must consider the confounding effect of maturation, early maturing players may be favoured for their ability to withstand increasing demands in higher-level youth AF.

Anthropometric and physiological characteristics of male soccer players according to their competitive level, playing position and age group: a systematic review

INTRODUCTION

The aim of the present systematic review was to profile soccer players' anthropometric, physiological, and physical attributes relative to different competitive levels, playing positions and age groups.

EVIDENCE ACQUISITION

The systematic search was conducted using different databases and according to the Population/Intervention or Exposure/Comparison/Outcome(s) [PICO] criteria.

EVIDENCE SYNTHESIS

The present review shows that the somatotype characteristics, percentage (%) of body fat, maximal oxygen uptake (VO2max), repeated-sprint ability (RSA), running speed, strength, and muscular power of the lower limbs were the most powerful discriminators between male soccer players of different competitive levels, playing positions, and age groups. Specifically, higher VO2max, muscle strength, muscular power (vertical jump height), running speed (10-30 m) and agility, and lower % of body fat were identified in elite soccer players (higher-level) compared to all other competitive levels (i.e., lower-level: sub-elite, amateur, recreational). As for the competitive level differences, higher VO2max, mean anaerobic power, RSA and sprint performances (5 to 20 m), and lower % of body fat and lower limbs' explosive capabilities (countermovement jump [CMJ] and squat jump [SJ]) were found in outfielders (forwards, midfielders, and defenders) as compared to goalkeepers, from a very youth age (8 years old). Concerning age-related performance, it appears that physical performance increased significantly with age.

CONCLUSIONS

These data, together with the fact that each position, age category, and playing level has a different physiological background in male soccer players, demonstrate that training programs should be individualized to each position, playing level and age category, as is already done with goalkeepers.

Pubertal development of body size and soccer-specific functional capacities in adolescent players

Pubertal growth in body size and functional capacities were examined in adolescent soccer players (n = 33). The average age at baseline was 10.9 (9.8-11.8 years). Peak height velocity (PHV) and growth curves for body mass and functional performance (countermovement jump, 15-m sprint, agility and Yo-Yo intermittent recovery test - level 1) were determined with Bayesian multilevel models. Estimates for PHV and age at PHV were 8.1 cm/year (95% credible interval: 4.2-18.5 cm/year) and 12.9 years (95% credible interval: 11.8-15.5 years), respectively. Peak body mass velocity occurred 0.48 year after PHV. Jump performance maximum velocity occurred about 2 years after PHV and peak sprint performance maximum velocity was coincident with PHV. Agility and intermittent endurance run performance showed a quadratic trend of improvement of performance, starting to level off at about 3-4 years after PHV. The modelling procedures were efficient to determine pubertal growth curves aligned for chronological age and age at PHV, considering individual differences in maturation when interpreting the development of performance in youth soccer.