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The study investigates relative age effects (RAE) in German youth soccer (Youth Bundesliga A: January 2004 to December 2005 and B: January 2006 to December 2007; highest league in German youth soccer) and its persistence in third-division players. Data from the 2022–2023 season (120 teams, 3,174 players) were analyzed using chi-square tests. Significant RAE was found in the A-series (p < .001), B-series (p < .001), and third-division professionals (p < .001). Notably, RAE was prominent among younger players but less evident in older third-division players (p = .116), indicating a diminishing selection effect with age and professional tenure. Coaches and talent managers are advised to consider RAE and additional factors like player maturity in talent selection for more efficient talent management strategies, especially in youth academies. [ABSTRACT FROM AUTHOR]

Copyright of Revista Académica Internacional de Educación Física is the property of Asociacion Cientifica Internacional de Educacion Fisica and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Background and Study Aim The warm-up phase in youth soccer can be used to introduce drills that do not find space within the training session. Core district exercises give stability to the trunk and hips, allowing for increased performance and reducing the risk of non-contact injuries. This study aims to test the effects of a warm up integrated with core stability exercises on the motor abilities in young soccer players. Material and Methods Young soccer players (n=32, 12.45±0.52 years, 1.49±0.05 m, 44±2.90 kg) were randomly divided into two groups: experimental (EG=17) and control group (CG=15). The EG performed an integrated warm-up with core stability tasks for 6 weeks (12 sessions). The CG followed the usual training schedule based on technical tactical and physical drills. Performance was assessed through broad jump, Hop test, Side Hop test, 10-meter sprint and 10x5-meter shuttle test. Results Data analysis returns some statistically significant differences in intergroup comparison (T1): for broad jump (p = .008), for left limb Hop test (p = .02), for right limb Hop test (p = .02), for left limb Side Hop (p = .03), for right limb Side Hop (p = .04), for sprint 10-meters (p = .002), for shuttle run 10x5-meters (p = .03). Conclusions The core stability exercises in the warm up seems to increase some performance correlated with the motor abilities stressed in the soccer. The warm up through appropriate modifications can represent, a useful and integrative moment to elicit more factors of performance and prevention. [ABSTRACT FROM AUTHOR]

Academy soccer players frequently train in the evening (i.e. 1700-2000 h), hence limited time to nutritionally prepare and recover due to schooling, travel and sleep schedules. Accordingly, we assessed timing and quantity of energy intake in the pre-training and post-training period. Over a 3-day in-season training period, male players (n=48; n=8 from under (U) 12, 13, 14, 15/16, 18 and 23 players) from an English Premier League academy self-reported dietary intake and physical activity levels (via the remote food photography method and activity diary, respectively) in the four hours pre- and post-training. Timing of pre-training energy intake ranged from 40 ± 28 mins (U15/U16 players) to 114 ± 71 mins (U18) before training and mean carbohydrate (CHO) intake ranged from 0.8±0.4 g.kg-1 (U23) to 1.5±0.9 g.kg-1 (U12). Timing of post-training energy intake ranged from 39 ± 27 mins (U14) to 70 ± 84 mins (U23) and mean CHO intake ranged from 1.6±0.8 g.kg-1 (U12) to 0.9±0.5 g.kg-1 (U14). In contrast to CHO, all age groups consumed sufficient protein intake in the post-training period (i.e. > 0.3 g.kg-1). We conclude academy soccer players habitually practice sub-optimal fuelling and recovery strategies, the consequence of which could impair growth, maturation and physical performance. [ABSTRACT FROM AUTHOR]

Background and Study Aim The process of soccer training for children and young people involves systematic exercise over an extended period to build a strong foundation of motor skills. These skills are designed to be both versatile and specific to the sport. The purpose of this research is to conduct a systematic review of literature related to the process of teaching grassroots football. This review aims to contribute to a better understanding of the strategies and methods employed in the development and training of young athletes. Material and Methods To conduct this review, studies were searched in the Web of Science (WOS) and Scopus databases from 2012 to 2022. The search focused on scientific articles addressing soccer teaching for children and girls up to 14 years old, using the keywords “children AND (football OR soccer) AND teaching.” The sample was limited to research in Spanish and English. The search yielded 149 articles, from which 19 studies were selected based on their titles and abstracts. Results The findings revealed two main categories: teaching methods and their impact on technical and tactical skills in grassroots football, and factors affecting technical-tactical performance in this context. The most significant findings emphasize the importance of a comprehensive approach to teaching grassroots football, which involves the coordination of knowledge, skills, strategies, decision-making, and technical abilities. Conclusions The review concludes that a variety of teaching approaches should be considered, and methodologies should be constantly evaluated to train future footballers with a deep understanding of the game. [ABSTRACT FROM AUTHOR]

The personal assets framework suggests that dynamic elements of (a) personal engagement in activities, (b) quality social dynamics, and (c) appropriate settings will influence an athlete's long-term outcomes of performance, personal development, and continued participation in sport. The aim of the present study was to conduct a case study of a Norwegian age-restricted team that was successful in promoting participation, performance, and positive development for individual participants and to investigate how the dynamic elements of activities, social dynamics, and settings have led to these long-term outcomes. The results indicated that the case is a best-practice example of successful attainment of personal development and long-term participation and performance through appropriate structure and application of the dynamic elements within the personal assets framework, including enjoyable peer-led play activities and quality practice, quality relationships with teammates and coaches, and access to facilities. [ABSTRACT FROM AUTHOR]

Study purpose. This study aimed at investigating the anthropometric and physiological characteristics that affect soccer skills in advanced-level youth soccer players. Materials and methods. Ninety advanced youth male soccer players from the U-18 division 1 soccer club were enrolled to participate in this study. The participants were classified into three different positions: defenders, midfielders, and forwards. The anthropometric profiles (height, weight, and body fat) and physiological variables (Y-balance test, Yo-Yo Intermittent Recovery Test Level 1, running-based anaerobic sprint test, sit-up test, countermovement jump test, drop jump test, arrowhead agility test, and 40-m sprint test) were assessed. Soccerspecific skills were measured using the Loughborough soccer passing and shooting protocol. Results. The multiple regression analysis revealed a statistically significant relationship between physical factors and the Loughborough soccer passing ability (R2 = 0.291, F(15, 74) = 2.200, p = 0.015). The results indicated that the relative maximum power displayed the strongest association with passing ability, followed by sit-up, countermovement jump without and with arm swing, and fatigue index. Concerning the shooting performance, the predictors accounted for 21.8% of the variance, with sit-up being the sole significant predictor among other factors. Conclusions. Our findings underscore the significance of relative maximum power, fatigue tolerance, muscular power, and core strength as valuable predictors for enhancing passing ability. In addition, abdominal strength emerged as a crucial indicator of shooting performance. Soccer coaches could use the essential information described in this study for talent identification purposes. [ABSTRACT FROM AUTHOR]

Change of direction (COD) maneuvers in soccer create tactical advantages, but also expose the player to an increased risk of injury. COD ability is commonly tested with pre-planned drills including cuts greater than 90°. These tests do not take into consideration positional differences players encounter during games. This case-series study used principal component analysis (PCA) to examine situational differences during COD movements between playing positions in youth soccer games. For each of the four teams included (26 females, 27 males), one game was analyzed using video-analysis. Two independent reviewers identified situational patterns and a PCA was used to examine differences between playing positions. Three principal components explained 89% of the variation in the data and were categorized as the total quantity of CODs, attacking/goal-scoring and defensive reacting types of CODs. One-way ANOVA on the individual principal component (PC) scores showed significant differences (p < 0.05) between centre midfielders, goalkeepers, and centrebacks in the quantity of CODs (PC1), and between wingers and fullbacks and centre backs in attacking/goal-scoring CODs (PC2), whereas PC3 was not different between playing positions. Differences between playing positions suggest that training and testing protocols in soccer could be enhanced to better match the individual and playing position-based needs. [ABSTRACT FROM AUTHOR]

Introduction: Dribbling is an important soccer skill that, when effective, allows players to overcome opponents. It can provide a strong tactical advantage; for this reason, all of its components (sprint, speed, and ball control) are fundamental to the development of young players. Dribbling can also be considered a decision-making process, and due to its characteristics, it is not always easy to study ecologically. Using a video analysis study, this research aimed to determine whether dribbling skills, specifically dribbling choice (i.e., decision-making), were related to U10 soccer players' quality. Methods: Several outcomes measures, divided into three categories, were taken during video analyses: (i) measures related to the efficacy of dribbling skill; (ii) measures related to the ability of players without the ball to support the player in possession; and (iii) measures related to ball circulation. These data were retrospectively assessed to whether the coaches had formed the teams in training through an implicit knowledge of the players' dribbling skills. Results: The percentage of accurate dribbling (that is, the ability to perform correct passes after a successful dribble) was found to be the variable that coaches may have implicitly used in creating the three groups differentiated by technical skills (p < 0.05). In fact, this percentage was 12.9%, 24.0%, and 48.1% for the groups with lower, average, and higher technical skills, respectively. Conclusion: Overall, the results demonstrate that dribbling accuracy has an important weight in the coach's evaluation of the technical skills level of young soccer players. [ABSTRACT FROM AUTHOR]

Introduction: In youth soccer, for examining injury prevention and exercise performance, most of the interventional studies concerning corrective postural asymmetries have applied general intervention programs, ignoring the specific individual corrective needs of each youth player separately. The aim, therefore, of the present study was to examine the effect of 8 weeks of an individualized corrective exercise intervention program on musculoskeletal asymmetries in young soccer players. Materials and Methods: Eighty young male soccer players (age: 14.4 ± 1.2 years; body height: 166.3 ± 9.6 cm; body mass: 59.1 ± 11.5 kg) participated in the current laboratory-based study. A battery of postural and musculoskeletal asymmetry evaluations were initially performed. After the completion of the initial assessment, each player was provided with an individual musculoskeletal asymmetry corrective exercise intervention program which lasted for 8-weeks, with the aim of restoring muscular asymmetries. Following the application of the intervention program, a re-evaluation of their musculoskeletal asymmetries was performed. Results: There was a significant improvement in the primary angle of trunk rotation (r = −0.56, p < 0.001), hamstring flexibility (right: r = −0.55, p < 0.001; left: r = −0.48, p < 0.001), hip external rotation (right: r = −0.46, p < 0.001; left: r = −0.26, p = 0.020), hip internal rotation (right: r = −0.26, p = 0.021; left: r = −0.35, p = 0.002), the opened-eyes Stork Test (right: r = −0.33, p = 0.003: left: r = −0.33, p = 0.003), the closed-eyes Stork Test (right: r = −0.39, p < 0.001; left: r = −0.43, p < 0.001), the Thomas test [right: (χ2(3) = 52.281, p = 0.001, γ ^ = −0.751; left: (χ2(3) = 45.832, p = 0.001, γ ^   = −0.696)] and of ankle prone passive dorsiflexion (flexed knees) (χ2(2) = 13.019, p = 0.005, V = 0.285). Conclusions: An 8-week individual corrective intervention exercise program may improve postural and musculoskeletal asymmetry status in young male soccer players. [ABSTRACT FROM AUTHOR]

Reliable talent identification and selection (TID) processes are prerequisites to accurately select young athletes with the most potential for talent development programmes. Knowledge about the agreement between scouts who play a key role in the initial TID in football is lacking. Therefore, the aim of the present study was to evaluate the agreement within four groups of a total of n = 83 talent scouts during rank assessment of under-11 male youth football players (n = 24, age = 11.0 ± 0.3 years) and to describe scouts' underlying approach to assess talent. Krippendorff's α estimates indicated disagreement of scouts' rankings within all groups of scouts (αA = 0.09, αB = 0.03, αC = 0.05, αD = 0.02). Scouts reported relying mainly on their overall impression when forming their final prediction about a player. Reportings of a consistent, structured approach were less prevalent. Taken together, results indicated that different approaches to TID may be associated with disagreement on selection decisions. In order to overcome disagreement in TID, football organisations are encouraged to establish a more structured process. Future research on the elaboration and benefit of ranking guidelines incorporating decomposed and independently evaluated sub-predictors is recommended to improve the reliability of TID. [ABSTRACT FROM AUTHOR]

This study aimed to examine the utility of inertial measurement unit (IMU) technology to identify angle, step-specific, and side-specific differences between youth soccer players with and without a history of lower limb injury during soccer-specific field tests. Thirty-two youths (mean age 16.4 years) who were elite soccer players (Females n = 13, Males n = 19) wore IMUs during pre- and postseason soccer-specific change-of-direction assessments. A response feature analysis was used to compare the change in peak resultant acceleration of the groups at a level of significance of p < 0.05. Statistical analysis revealed significant differences in change of peak resultant acceleration of right leg final foot contact in a 180° pivot turn (p = 0.012, ES = 1.0) and a 90° cut (p = 0.04, ES = 0.75) between the two groups. These data suggest that players with a history of lower limb injury might experience greater angle and side-specific change within a season in peak resultant acceleration when compared with injury-free athletes. This study demonstrates that IMUs may present a useful method to analyze youth soccer players' change of direction movement after returning to play. These results can inform future studies investigating player monitoring and may prove to be a useful tool for coaches when designing individualized training programs in this population. [ABSTRACT FROM AUTHOR]

This study aimed to determine whether vertical jump performance differs among youth players with different performance levels. A total of 84 youth male soccer players from the U19 category were recruited. The players were divided into the elite (EG) and sub-elite (SEG) groups based on their performance level. The vertical jump (VJ) performance during countermovement jump with free arms (CMJFA) and drop jump (DJ) were measured using two force platforms Kistler B8611A at a sampling rate of 1000 Hz (KISTLER Instrumente AG, Switzerland). The following outcome variables were calculated in all participants: vertical jump height (VJH), vertical ground reaction force (VGRF), and force impulse (FI) in absolute and relative values. Data analysis showed no significant differences (p>0.05) with trivial to small effects in VJH for both jump types (CMJFA and DJ) between EG and SEG. FIrelative provides a good indication of VJH in comparison with the other kinematic variables selected in this study. The leg muscle mass (LMM) ratio normalised to body mass provides a better association with VJH than the other selected morphological variables in this study, although a small effect size was observed. VJH does not appear to be a distinguishing feature among soccer players in the first two performance levels in the U19 category. Therefore, the results may not be sensitive enough to differentiate the performance levels, especially when the difference is only in one performance level. Future research should consider using other parameters, such as the eccentric rate of force development or reactive strength index, as recommended in a previous study. [ABSTRACT FROM AUTHOR]

Background: Participation in soccer training is beneficial for the development of energetic motor abilities and coordination abilities. The aim of this study was to evaluate the effect of closed-skill bodyweight resistance exercises which differ in their jumping movement structure, on jumping skills in youth soccer players. It was hypothesized that the examined exercises provide a better stimulus than soccer training for jumping development. Methods: Twenty-six young soccer players participated in the study. They were assigned to a strength training soccer group (SSG, n = 15) or a soccer group (SG, n = 11). The SSG realized a 9-week strength training in addition to soccer training. The following measurements were taken: countermovement jump with arm swing (CMJas), countermovement jump without arm swing (CMJ), an indicator of coordination of the upper limbs (CMJas -- CMJ), and anaerobic power of CMJ (Pmax CMJ). Results: The obtained results showed similar improvements in jumping skills in both SSG and SG groups. Moreover, the results revealed a difference between both groups in pre- and post-training conditions for correlation coefficients observed between jumping variables. Conclusions: The strength exercises used in this study are not more beneficial for developing jumping skills than conventional soccer training among youth soccer players. Moreover, the strength training sessions should be based on a model of motor control in soccer players. [ABSTRACT FROM AUTHOR]

Copyright of Retos: Nuevas Perspectivas de Educación Física, Deporte y Recreación is the property of Federacion Espanola de Asociaciones de Docentes de Educacion Fisica and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The aims of the study were to examine the test–retest reliability of force-time (F-T) characteristics and F-T curve waveform of bilateral and unilateral countermovement jumps (CMJ) in elite youth soccer players and to evaluate the effects of competitive match-play on CMJ performance. 16 male youth soccer players completed CMJs on two separate occasions to determine reliability, and immediately pre, post and 48 h following a competitive match. Coefficient of variation (CV%), Intra-class correlation coefficient (ICC) and limits of agreement were used to assess reliability of discreate CMJ variables. Single factor repeated measures ANOVA were used to determine the effects of match play. Statistical parametric mapping was used to evaluate the repeatability of the CMJ force-time waveform and the effects of match play. Jump height had limited reliability in all three jumps and only a select few jump specific F-T variables were found to be reliable (CV < 10%, ICC > 0.5). Select variables were reduced immediately post game but recovered 48 h post game. The F-T curve waveform was found to be repeatable but did not differ following match-play. This study suggest that select F-T variables change following match-play and may be suitable tools to allow practitioners to detect decrements in performance. These data may help inform practitioners to use the most appropriate F-T variables to assess fatigue and recovery, with implications for performance and injury risk. [ABSTRACT FROM AUTHOR]

Introduction: Biological maturity level has shown to affect sport performance in youths. However, most previous studies have used noninvasive methods to estimate maturity level. Thus, the main aim of the present study was to investigate the association between skeletal age (SA) as a measure of biological maturation level, match locomotion, and physical capacity in male youth soccer players. Method: Thirty‐eight Norwegian players were followed during two consecutive seasons (U14 and U15). Match locomotion was assessed with GPS‐tracking in matches. SA, assessed by x‐ray, physical capacities (speed, strength and endurance) and anthropometrics were measured in the middle of each season. Analysis of associations between SA, match locomotion, and physical capacities were adjusted for the potential confounding effect of body height and weight. Results: In matches, positive associations were found between SA and maximal speed and running distance in the highest speed zones. Further, SA was associated with 40 m sprint time and countermovement jump (CMJ) height, and with intermittent‐endurance capacity after adjusting for body height (U14). Associations between SA and leg strength and power, and between SA and absolute VO2max were not significant after adjusting for body weight. There was no association between SA and total distance covered in matches. Conclusion: Biological maturity level influence match locomotion and performance on physical capacity tests. It is important that players, parents and coaches are aware of the advantages more mature players have during puberty, and that less mature players also are given attention, appropriate training and match competition to ensure proper development. [ABSTRACT FROM AUTHOR]

Relative age effect (RAE) has been found to be particularly pronounced between 13 and 15 years of age in male football. However, the extent to which the phenomenon varies within a country demands a more comprehensive approach. To examine the effects of geographical location (north; centre-north; centre-south; south; islands), team quality (top-ranked; middle-ranked; bottom-ranked) and playing position (goalkeeper; defender; midfielder; forward) on the birthdate distribution (Q1: January–March; Q2: April–June; Q3: July–September; Q4: October–December) of U14 Portuguese players selected for the national inter-association tournament Lopes da Silva. A total of 2,693 players (mean age: 14.12 ± 0.38 years), selected by the 22 regional football associations for the last seven editions of the tournament (2013–2019), was included in the sample. Chi-square analysis showed a small-to-medium RAE in the U14 cohort compared to the general Portuguese male population (p <.01). Furthermore, the multinomial logistic regression model revealed that the probabilities of selecting Q1 players (vs. Q4) differed (p <.01) based on geographical location (increases of 76.3% in the north and 87.3% in the centre-north zone compared to the regional teams from islands) and team quality (increase of 94.6% in top-ranked compared to the bottom-ranked teams). The playing position did not affect the magnitude of RAE. Our findings confirm that besides being present in U14 Portuguese male football, the magnitude of RAE is influenced by demographic factors. This study also supports the notion that coaching staffs tend to choose players based on attributes associated with chronological age, seeking to achieve short-term competitive outcomes. [ABSTRACT FROM AUTHOR]

The fact that potentially skilled, but biologically later-maturing athletes are less likely to be selected into talent development programmes (TDP) can represent a failure of Talent Identification (TID) in sports. To overcome maturation selection biases, maturation independent TID should be established to include less mature, but talented athletes in TDP more frequently. Using a randomised parallel-group design, this study aimed to evaluate the effect of labelling under-11 (U11) Swiss male youth football players (n = 24, age = 11.0 ± 0.3 years) via maturation-ordered shirt numbers during rank assessment by talent scouts (n = 83, scout experience = 4.8 ± 2.4 years). Following observation of video recorded selection tournaments, player-labelling "informed" scouts were significantly more likely to rank less mature players higher on their player potential, t(81) = 2.57, p =.012, d = −0.6, 95% CI [−1.00, −0.13], than "uninformed" scouts. As altered rankings assisted less mature players, player-labelling may offer a practical and feasible strategy to improve TID by removing possible maturation selection biases. To address maturation selection biases and the potential positive impact of player-labelling more broadly, further research on both male and female athletes in various age categories and sports contexts is recommended. [ABSTRACT FROM AUTHOR]

This case summarizes the rehabilitation and return to play management of a 17-year-old elite male soccer player who required surgical stabilization of an Osteochondritis Dissecans (OCD) lesion of the trochlea groove. Trochlea groove lesions represent <1% of OCD cases, resulting in limited evidence to inform practice. The case was initially identified as antalgic running gait, and at this point the player revealed progressively worsening knee pain (over preceding 2 months) which presented as patellofemoral pain with a small knee effusion and quadriceps atrophy present on assessment. No improvement in symptoms after 2 weeks of unloading (no running) and traditional patellofemoral treatment prompted magnetic resonance imaging and computed tomography scans to inform surgical intervention. We present a summary of the four-stage rehabilitation process defined by objective assessments, resulting in a successful return-to-play 24 weeks post-surgery. This case advocates consideration of OCD in the assessment of persistent knee pain in young athletes. [ABSTRACT FROM AUTHOR]

Altered movement patterns during single-leg movements in soccer increase the risk of lower-extremity non-contact injuries. The identification of biomechanical parameters associated with lower-extremity injuries can enrich knowledge of injury risks and facilitate injury prevention. Fifty-six elite youth soccer players performed a single-leg drop landing task and an unanticipated side-step cutting task. Three-dimensional ankle, knee and hip kinematic and kinetic data were obtained, and non-contact lower-extremity injuries were documented throughout the season. Risk profiling was assessed using a multivariate approach utilising a decision tree model (classification and regression tree method). The decision tree model indicated peak knee frontal plane angle, peak vertical ground reaction force, ankle frontal plane moment and knee transverse plane angle at initial contact (in this hierarchical order) for the single-leg landing task as important biomechanical parameters to discriminate between injured and non-injured players. Hip sagittal plane angle at initial contact, peak ankle transverse plane angle and hip sagittal plane moment (in this hierarchical order) were indicated as risk factors for the unanticipated cutting task. Ankle, knee and hip kinematics, as well as ankle and hip kinetics, during single-leg high-risk movements can provide a good indication of injury risk in elite youth soccer players. [ABSTRACT FROM AUTHOR]

Considering that most professional academies seek to optimize the early detection and physical development of their younger players, the purpose of this study was to examine the anthropometric and physical fitness characteristics in a large cross-sectional sample of youth soccer players in Eastern Europe, starting from a very young age during their in-season period. Three hundred and thirteen soccer players (n = 313), grouped into eight age categories, participated in the study. On the basis of chronological age, the group categories were: 7 (n = 26), 8 (n = 41), 9 (n = 46), 10 (n = 48), 11 (n = 42), 12 (n = 47), 13 (n = 43), and 14 years old (n = 20). The players underwent an anthropometric evaluation, flexibility, handgrip strength, vertical jump performance, speed, and agility assessments. A one-way multivariate analysis of variance (MANOVA) indicated significant differences in the anthropometric and physical fitness variables based on chronological age (F = 13.40, p < 0.05, Wilk's Λ = 0.08, partial η2 = 0.30). Concurrently, there were significant growth and physical fitness differences even in players born in the same chronological year. It is believed that the results have important practical implications, especially for those involved in youth soccer. Based on our results, coaches should contemplate speed and agility development in training sessions starting from a much younger age, as sprinting while changing directions has been considered an essential prerequisite in soccer. [ABSTRACT FROM AUTHOR]

Talent identification in football is complex. Research regarding talent indicators that predict selection into professional academies is increasingly multi-disciplinary, though is typically cross-sectional, failing to consider whether the rate of change of those indicators influences selection. The aim of this study was to determine if longitudinal changes in talent indicators are associated with selection into a professional football academy. A total of 110 Dutch male football players (aged 8–12) playing in a youth development programme of a professional club were included in the study. Players were assessed regularly on their anthropometry, physical fitness, gross motor coordination, technical ability, and psychosocial capacities over four years. A subset of players was then selected into the academy. Cross-sectional and longitudinal analyses revealed the indicators that best predicted selection. The best indicator was the 30 m sprint speed, with prediction not improving when including other predictors or their rate of change. The individuals that the club ultimately selected at age 12 could have been predicted well above chance levels using the sprint speeds at age nine or ten. The relative consistency of the rate of improvement in indicators across participants meant that the rate at which they developed played little role in selections. [ABSTRACT FROM AUTHOR]

Purpose: To assess and compare the effects of 8 wk of in-season (2 sessions/wk) low- and high-volume plyometric training (PT) on measures of physical fitness in prepubertal male soccer players. Methods: A total of 25 soccer players were randomly assigned to a low-volume PT group (LPT; n = 13, age 12.68 ± 0.23 y, age at peak height velocity [APHV] 14.25 ± 0.29 y, maturity offset -1.57 ± 0.29 y) or a high-volume PT group (HPT; n = 12, age 12.72 ± 0.27 y, APHV 14.33 ± 0.77 y, maturity offset -1.61 ± 0.76 y). A linear-sprint test (5-m, 10-m, 20-m, and 30-m), change-of-direction (CoD) test, and vertical- (squat-jump [SJ]), countermovement- (CMJ), and horizontal-jump (standing long jump [SLJ]) test were carried out before and after 8 wk of PT. Results: There was a significant main effect of time for sprint outcomes (5-m, P = .005, ES = 0.86; 10-m, P = .006, ES = 0.85; 20-m, P = .03, ES = 0.64, and 30-m, P = .05, ES = 0.57), CoD (P = .002, ES = 0.96), SJ (P = .008, ES = 0.81; CMJ, P = .01, ES = 0.73), and SLJ ability (P = .007, ES = 0.83). There were no significant training group x time interactions in any measured outcomes. Conclusions: After 8 wk of training, results showed similar performance improvement on measures of sprint time, CoD, and jumping ability between LPT and HPT groups. From a time-efficiency perspective, it is recommended to use LPT in prepubertal male soccer players to improve their proxies of athletic performance. [ABSTRACT FROM AUTHOR]

Talent identification in youth soccer is a complex decision-making process that requires selectors to judge an individual's future potential. While there has been considerable research into the performance characteristics of talented players, investigators have limited consensus on the best approach to assess soccer skills. Most of the research explains why we should measure skill instead of how we go about assessing skill. Therefore, the current scoping review aimed to synthesize and analyse skill assessments in youth soccer. Four electronic databases (EBSCO, ProQuest, PubMed, and Scopus) were searched for relevant studies. Information regarding the sample characteristics and methodological design of the skill assessments were extracted, synthesised, and presented in a qualitative analysis. Overall, 226 skill assessments were used across the 93 included studies. Male players from different ages (U/7-U/23) and playing levels comprised most (89%) of the collective sample. The majority of assessments were performed in settings not representative of football match-play (68%), focused on offensive skills (99%), and included skill outcome measures (95%). The variability of assessments highlights some confusion about the best way to assess soccer skill, potentially limiting selectors ability to identify skilful players. Ultimately, this will impact the number of quality players within the talent pool. [ABSTRACT FROM AUTHOR]

In 2019, numerous championships of youth categories soccer national teams were held. In the present study, we analyzed the existence of the Relative Age Effect (RAE) in four major male championships that, due to their importance and participating teams, most likely brought together the great bulk of the players who will dominate professional soccer in the next decade. Participants were professional and amateur youth male soccer players who participated in the last international championships: UEFA European Under-21 Championship (2017–2019); UEFA European Under-19 Championship (2019); South American Youth Football Championship (also known as Conmebol U-20) (2019); and FIFA U-20 World Cup (2019), with 823 players (20.25 ± 0.84 years). In the four championships analyzed, the existence of RAE was found for all players (p < 0.001). Analyzing the players when considering their position on the pitch and their championship, RAE was found, statistically significant, in 10 of the 16 classifications. New generations of elite soccer players arrive with a clear bias in the selection of talent; an unfair bias, based on unequal opportunities in early categories, which should be reviewed by sports authorities. [ABSTRACT FROM AUTHOR]

Predicting and avoiding an injury is a challenging task. By exploiting data mining techniques, this paper aims to identify existing relationships between modifiable and non-modifiable risk factors, with the final goal of predicting non-contact injuries. Twenty-three young soccer players were monitored during an entire season, with a total of fifty-seven non-contact injuries identified. Anthropometric data were collected, and the maturity offset was calculated for each player. To quantify internal training/match load and recovery status of the players, we daily employed the session-RPE method and the total quality recovery (TQR) scale. Cumulative workloads and the acute: chronic workload ratio (ACWR) were calculated. To explore the relationship between the various risk factors and the onset of non-contact injuries, we performed a classification tree analysis. The classification tree model exhibited an acceptable discrimination (AUC=0.76), after receiver operating characteristic curve (ROC) analysis. A low state of recovery, a rapid increase in the training load, cumulative workload, and maturity offset were recognized by the data mining algorithm as the most important injury risk factors. [ABSTRACT FROM AUTHOR]

This study aimed to investigate the hamstring flexibility rate among prepubertal soccer players from U8 to U12 and the role of age and soccer years of practice on the course of hamstring flexibility. Six hundred eleven young Italian soccer players from a local soccer school in Turin were recruited for this research and assigned to each group according to their chronological age (U8 = 124 players; U9 = 130 players; U10 = 151 players; U11 = 89 players; and U12 = 120 players). Hamstring flexibility was measured using the Sit and Reach Test (SAR), while data analysis was run using a one-way analysis of variance (one-way ANOVA). Furthermore, Tuckey's post hoc was used to determine differences among the classes of age. Finally, a bivariate ordinal regression analysis was used to evaluate a potential association between age categories and hamstrings flexibility. In addition, multivariable ordinal regression was used to analyze this relationship adjusted for the Body Mass Index (BMI). The one-way ANOVA showed significant differences in flexibility among groups (F = 32.76, P < 0.0001). Tuckey's post hoc identified significant differences between U8 and U10 (p < 0.01; −2,39 cm of hamstring stretching), U8 and U11 (p < 0.05; −2.19 cm), U8 and U12 (p < 0.0001; −5.90), U9 and U12 (p < 0.0001; −4.98 cm), U10 and U12 (p < 0.0001; −3.5 cm), U11 and U12 (p < 0,001; −3.70 cm). In the bivariate ordinal regression analysis, there was a negative association between the age categories and hamstrings flexibility (R 2 = 0.137; p < 0.0001). The association persisted in multivariable ordinal regression analysis adjusted for BMI (R 2 = 0.138; p < 0.0001). This study underlines changes in hamstring flexibility across different age groups of prepubertal soccer players. The older and more experienced in soccer are less flexible than the younger, considering the hamstring muscles. Thus, appropriate stretching protocols should be included in prepubertal soccer training to avoid the risk of lead players to excess hamstring tightness. [ABSTRACT FROM AUTHOR]

The Athletic Identity Measurement Scale (AIMS) is a popular measure of Athletic Identity (AI). The purpose of the present study was to investigate the factor structure (7-item single-factor and three-factor model; Social Identity, Exclusivity and Negative Affectivity) of the AIMS within youth academy soccer players. A total of 259 male youth academy soccer players aged 12-18 years completed the AIMS. A series of confirmatory factor analyses and independent cluster modelling indicated support for the 7-item single-factor (AI) and the three-factor models, but not within the same analysis. The results support the use of AIMS for the measurement of AI in elite male youth soccer players. Practitioners seeking to explore AI in youth soccer populations should use the three-factor model to glean further insight from the three subscales to support the design of more specific interventions where appropriate. [ABSTRACT FROM AUTHOR]

This study examined the effectiveness of a longitudinal 5C coaching intervention (Harwood, 2008), focused on promoting behavioral responses associated with commitment, communication, concentration, control, and confidence in youth soccer players. Five players, their parents and a youth academy soccer coach participated in a single-case multiple-baseline across individuals design with multiple treatments. Following baseline, the coach received sequential education in the principles of each C subsequent to integrating relevant strategies in their coaching sessions. During the five intervention phases, players completed assessments of their behavior in training associated with each C, triangulated with observation- based assessments by the coach and the players' parents. Results indicated psychosocial improvements with cumulative increases in positive psychosocial responses across the intervention for selected players. Changes in player behavior were also corroborated by parent and coach data in conjunction with postintervention social validation. Findings are discussed with respect to the processes engaged in the intervention, and the implications for practitioners and applied researchers. [ABSTRACT FROM AUTHOR]

The purpose of this study was to examine the effects of a 6-month high- or moderate-intensity total-body circuit training (CT) program on physical fitness in prepubertal soccer players. Sixty-seven prepubertal boys with a mean age of 11.2 ± 0.7 years completed the study. Participants from a soccer academy were randomly assigned either to a high-intensity CT group (HCT, n = 22) or a moderate-intensity CT group (MCT, n = 24). A control group (CON, n = 21) comprised age-matched individuals who were not involved in any regular training regime. CT protocols were included in the experimental group's training sessions 3 times per week over 24 weeks as part of their usual weekly training regime. Based on the HR zone method, CT protocols included high- or moderate-intensity (85–95% HRmax or 75–85% HRmax) series of 3 different sets of upper- and lower-body strength exercises with articular and muscular mobilization, all culminated with 40-m sprints. Physical fitness was evaluated by the Eurofit test which included the flamingo balance (FLB), plate tapping (PLT), sit-and-reach (SAR), standing broad jump (SBJ), handgrip (HG), sit-ups (SUP), bent arm hang (BAH), 10×5 m shuttle run (SHR), and the Physical Working Capacity test (PWC170). The two-way ANOVA indicated group×time interaction effects for 5 components: the largest was for the SBJ (F2,63 = 42.895, p < 0.001, η2 = 0.577), and the lowest for the SHR (F2,63 = 5.006, p < 0.01, η2 = 0.137) indicating better improvements in the HCT compared to the MCT group. Furthermore, for HCT and MCT groups the highest pre- to post-intervention percentage changes were for the FLB and the SAR, while in the CON group the changes of all physical fitness components were not significant (p < 0.05). In conclusion, the intensity-controlled total-body CT protocol incorporated into a standard soccer training program is effective for enhancement in physical fitness performance in prepubertal soccer players. [ABSTRACT FROM AUTHOR]

Purpose: To examine the influence of player number, bout duration and their interaction on small-sided game (SSG) variations in running performance, perceptual response and technical components in under-14 soccer players. Methods: Eleven players randomly performed 3v3 and 5v5 SSG of 4 × 5 min, 2 × 10 min and 20 min duration. Total distance (TD), distance covered at high-intensity running (HIR), sprinting and > 80% peak speed of the Carminatti's test (PST-CAR) were analyzed every 5-min epoch. Rating of perceived exertion (RPE) and players' technical performance were also assessed. Results: TD (p < 0.001) and distance > 80% PST-CAR (p = 0.017) were significantly greater in 4 × 5 min than in the other conditions. The distance covered > 80% PST-CAR was significantly (p = 0.026) reduced from the 1st and 2nd to the 4th quarter (Δ = − 34% and − 23%, respectively) during the 3v3, while no decrement was found in the 5v5. A downward trend over time was observed for TD (p = 0.088), HIR (p = 0.060) and sprinting (p = 0.085). Players covered more distance > 80% PST-CAR during the 3v3 first quarter (p = 0.009). RPE was affected by player number and bout duration (p < 0.0001), with higher RPE during 3v3 and 1 × 20 min conditions. Significantly more successful passes, contacts with the ball, ball involvement, goals scored and shots on target were achieved during 3v3. Conclusions: Shorter bout duration elicited greater TD and distance > 80% PST-CAR. A combined influence of player number and period of the game on high-intensity activities was evident. The RPE was significantly influenced by the player number and bout duration. The 5v5 elicited less successful technical outcomes. The 3v3 may be useful for work-rate enhancement and integrated training. [ABSTRACT FROM AUTHOR]

Copyright of Lúdica Pedagógica is the property of Universidad Pedaggica Nacional and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Physical Education (20736452) is the property of Republic of Iraq Ministry of Higher Education & Scientific Research (MOHESR) and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Background: Change-of-direction (CoD) is a necessary physical ability of a field sport and may vary in youth players according to their maturation status. Objectives: The aim of this study is: to compare the effectiveness of a 6-week CoD training intervention on dynamic balance (CS-YBT), horizontal jump (5JT), speed (10 and 30-m linear sprint times), CoD with (15 m-CoD + B) and without (15 m-CoD) the ball, in youth male soccer players at different levels of maturity [pre- and post-peak height velocity (PHV)]. Materials and Methods: Thirty elite male youth soccer players aged 10–17 years from the Tunisian first division participated in this study. The players were divided into pre- (G1, n = 15) and post-PHV (G2, n = 15) groups. Both groups completed a similar 6-week training program with two sessions per week of four CoD exercises. All players completed the following tests before and after intervention: CS-YBT; 5 JT; 10, 30, and 15 m-CoD; and 15 m-CoD + B, and data were analyzed using ANCOVA. Results: All 30 players completed the study according to the study design and methodology. Adherence rate was 100% across all groups, and no training or test-related injuries were reported. Pre-PHV and post-PHV groups showed significant amelioration post-intervention for all dependent variables (after test > before test; p < 0.01, d = 0.09–1.51). ANOVA revealed a significant group × time interaction only for CS-YBT (F = 4.45; p < 0.04; η2 = 0.14), 5JT (F = 6.39; p < 0.02; η2 = 0.18), and 15 m-CoD (F = 7.88; p < 0.01; η2 = 0.22). CS-YBT, 5JT, and 15 m-CoD improved significantly in the post-PHV group (+ 4.56%, effect size = 1.51; + 4.51%, effect size = 1.05; and -3.08%, effect size = 0.51, respectively), more than the pre-PHV group (+ 2.77%, effect size = 0.85; + 2.91%, effect size = 0.54; and -1.56%, effect size = 0.20, respectively). Conclusion: The CoD training program improved balance, horizontal jump, and CoD without the ball in male preadolescent and adolescent soccer players, and this improvement was greater in the post-PHV players. The maturity status of the athletes should be considered when programming CoD training for soccer players. [ABSTRACT FROM AUTHOR]

Cardiac modifications to training are a product of the genetic pre-disposition for adaptation and the repetitive haemodynamic loads that are placed on the myocardium. Elite pre-adolescent athletes are exposed to high-intensity training at a young age with little understanding of the physiological and clinical consequences. It is unclear how right ventricular (RV) structure and function may respond to this type of stimulus. The aim of this study was to compare RV structure and strain across the cardiac cycle and within individual segments in elite soccer players (SP) and controls (CON).Methods: Twenty-two highly trained, male pre-adolescent SP and 22 age-and sex-matched recreationally active individuals CON were investigated using 2D echocardiography, including myocardial speckle tracking to assess basal, mid-wall, apical and global longitudinal strain and strain rate during systole (SRS) and diastole (SRE and SRA).Results: greater RV cavity size was identified in the SP compared to CON (RVD1 SP: 32.3 ± 3.1 vs. CON: 29.6 ± 2.8 (mm/m2)0.5; p = 0.005). No inter-group differences were noted for peak global RV strain (SP: - 28.6 ± 4.9 vs CON: - 30.3 ± 4.0%, p = 0.11). Lower mid-wall strain was demonstrated in the SP compared to CON (SP: - 27.9 ± 5.8 vs. CON: - 32.2 ± 4.4%, p = 0.007).Conclusion: Soccer training has the potential to increase RV size in pre-adolescent players. The unique segmental analyses used in this study have identified inter-group differences that were masked by global strain evaluations. The clinical and physiological implications of these findings warrant further investigation. [ABSTRACT FROM AUTHOR]

Soccer and its intense workouts cause lactate accumulation and extensive metabolic changes. This study, therefore, aimed to compare the percentage of maximum heart rate (%HRmax), blood lactate, growth hormone (GH), and insulin-like growth factor‑1 (IGF-1) responses across different formats of small-sided games (SSG) in young soccer players. Twenty-four soccer players (mean age: 17.1 ± 1.12 years, weight 67.28 ± 1.65 kg and body mass index 20.8 ± 1.18 kg/m2) were randomly divided into three equal groups, including control, 2 vs. 2 (8 periods of 2 min separated by 1 min of passive recovery, with a pitch of 20 m × 25 m) and 4 vs. 4 (4 periods of 4 min separated by 2 min of passive recovery, with a pitch of 28 m × 35 m). Blood samples were taken immediately before and after small-sided games. The results showed that the heart rate increased significantly in young soccer players at different minutes of SSG (p ≤ 0.05). The comparison of these two SSG did not show any significant differences on lactate and somatotropic hormone concentrations (p > 0.05), although each alone significantly increased lactate, GH and IGF‑1 levels compared to control group (p < 0.05). Hence, it can be concluded that due to the sufficient intensity of these two modes of SSG, the cellular relationship between the GH/IGF‑1 axis and lactate helps improve the physiological capacity of young soccer players. However, further studies were needed to consider more accurate effects of these variables (lactate, GH and IGF-1) with two SSG modalities (2 vs. 2 and 4 vs. 4). [ABSTRACT FROM AUTHOR]

Being one of the most prominent globalized sports, soccer played at club, national, and continental levels has a relevant societal role. At present, the specific competencies, interests, and languages of the different actors involved in the selection, development, and support of long-lasting careers of players might limit opportunities for potential talented players. Unless the cultural environment of soccer resolves the gaps between empirical results and actual soccer strategies, scientific discussion relating to the effectiveness of talent selection and development remains limited. This commentary is intended to highlight the need for developmental programs to prepare soccer personnel for a transdisciplinary dialogue, which could foster a future development of this sport. Finally, in considering the wide soccer-related employment opportunities at local, national, and international levels, the need for a clear qualification framework is crucial. [ABSTRACT FROM AUTHOR]

Copyright of Revista Andaluza de Medicina del Deporte is the property of Centro Andaluza de Medicina del Deporte and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The aim of this study was to investigate inter-day and -week as well as intra- and inter-individual variation of selected biomarkers in high-performance youth soccer players to assist practitioners interpreting player's internal load to counteract underperformance and unwanted health risks. Eleven male youth soccer players were tested multiple times during two 3-week periods at midpoint (3-wkmid) and at the end (3-wkend) of the first half of a German under-19 1. Bundesliga season. The levels of creatine kinase (CK), urea, and C-reactive protein (CRP) were measured during 3-wkmid and 3-wkend each Monday, Wednesday, and Friday. In 3-wkmid the CK median was 14% higher (241 vs. 212 U/L) compared to 3-wkend (P = 0.26, ES = 0.16). Overall, the medians of CK, urea (P = 0.59, ES = 0.08), and CRP (P = 0.56, ES = 0.10) during 3-wkmid did not differ to the values of 3-wkend. Daily coefficient of variations (CVs) ranged from 22 to 71% (CK), 17 to 37% (urea), and 9 to 164% (CRP). Individual medians ranged from 101 to 350 U/L (CK), 23 to 50 mg/dL (urea), and 0.6 to 1.1 mg/L (CRP). High intra-individual variability was demonstrated by large intra-individual CVs (medians: CK 50%, urea 18%, and CRP 45%). Our data show (i) large inter-day and inter-week variability of all biomarkers, depending on the external load and (ii) considerable inter- and intra-individual parameter variations. Creatine kinase concentrations could sensitively reflect soccer-specific loads during the season. [ABSTRACT FROM AUTHOR]

To compare the effects of short-term (i.e., 7 weeks) plyometric jump training applied before (PJT-B) or after (PJT-A) soccer practice on components of physical fitness in young soccer players, a single-blind randomized controlled trial was conducted. Postpubertal boys aged 17.0 ± 0.5 years were allocated to 3 groups: PJT-B (n = 12), PJT-A (n = 14), and control (CON; n = 12). The outcome measures included tests to evaluate 20-m speed, standing long jump (SLJ), squat jump (SJ), countermovement jump (CMJ), and drop jump (DJ), 20-m multistage shuttle run endurance (MSSRT), and Illinois change-of-direction speed (ICODT). Although the CON performed soccer-specific training, the PJT-A and PJT-B groups conducted the same soccerspecific sessions but replaced ;11% of their time with plyometric training. The PJT-B group performed plyometric exercises after a warm-up program, and the PJT-A group conducted plyometric exercises ;10 minutes after the completion of soccer training. Analyses of variance were used to detect differences between groups in all variables for pretraining and posttraining tests. Main effects of time (all p, 0.01; d = 0.19-0.79) and group 3 time interactions (all p# 0.05; d = 0.17-0.76) were observed for all examined variables. Post hoc analyses revealed significant increases in the PJT-B group (SLJ: 9.4%, d = 1.7; CMJ: 11.2%, d = 0.75; 20-m MSSRT: 9.0%, d = 0.77) and the PJT-A group (SLJ: 3.1%, d = 0.7; CMJ: 4.9%, d = 0.27; 20-m MSSRT: 9.0%, d = 0.76). Post hoc analyses also revealed significant increases in the PJT-B group (20-m speed: 27.4%, d = 0.75; 20-cm DJ reactive strength index: 19.1%, d = 1.4; SJ: 6.3%, d = 0.44; ICODT results: 24.2%, d = 1.1). In general, our study revealed that plyometric training is effective in improving measures of physical fitness in young male soccer players when combined with regular soccer training. More specifically, larger traininginduced effects on physical fitness were registered if plyometric training was conducted before soccer-specific training. [ABSTRACT FROM AUTHOR]

Copyright of Retos: Nuevas Perspectivas de Educación Física, Deporte y Recreación is the property of Federacion Espanola de Asociaciones de Docentes de Educacion Fisica and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

For the first time we aimed to: (1) assess fat-free mass (FFM) and RMR in youth soccer players, (2) compare measured RMR to estimated RMR using previously published prediction equations, and (3) develop a novel population-specific prediction equation. In a cross-sectional design, 99 males from a Premier League academy underwent assessments of body composition (DXA) and RMR (indirect-calorimetry). Measured RMR was compared to estimated values from five prediction equations. A novel RMR prediction equation was developed using stepwise multiple regression. FFM increased (P<0.05) between U12 (31.6±4.2 kg) and U16 (56.3±5.3 kg) after which no further increases occurred (P>0.05). RMR in the U12s (1655±195 kcal.day−1), U13s (1720±205 kcal.day−1) and U14s (1846±218kcal.day−1) was significantly lower than the U15s (1957±128 kcal.day−1), U16s (2042±155 kcal.day−1), U18s (1875±180 kcal.day−1) and U23s (1941±197 kcal.day−1) squads (P>0.05). FFM was the single best predictor of RMR (r2=0.43; P<0.01) and was subsequently included in the novel prediction equation: RMR (kcal.day−1) = 1315 + (11.1 x FFM in kg). Both FFM and RMR increase from 12-16 years old, thus highlighting the requirement to adjust daily energy intake to support growth and maturation. The novel prediction RMR equation developed may help to inform daily energy requirements. [ABSTRACT FROM AUTHOR]

This mixed-longitudinal prospective study examined the development of psychological characteristics of developing excellence in relation to the career progression of elite youth football players. In a 20-month period, 111 academy football players aged 11–16 completed the Psychological Characteristics of Developing Excellence Questionnaire (PCDEQ) on 1–5 occasions. This combination of single and repeated assessments resulted in a mixed-longitudinal sample of 226 completed PCDEQs. Players were then prospectively tracked, and their scholarship status assessed at follow-up, at age U17. Multilevel modelling revealed that coping with performance and developmental pressures scores increased with age, and that Category 1–2 academy scholars (4.35 ± 0.61) scored higher than Category 3–4 academy scholars (3.99 ± 0.67) and non-scholars (4.02 ± 0.78) (p <.05). Evaluating performances and working on weaknesses scores increased with age for Category 1–2 academy scholars (U12-U14 vs. U15-U16 = 5.16 ± 0.48 vs. 5.38 ± 0.45), compared to non-scholars (U12-U14 vs. U15-U16 = 5.11 ± 0.59 vs. 5.03 ± 0.71) (p <.05). Imagery use during practice and competition scores decreased with age (U12-U14 vs. U15-U16 = 4.45 ± 0.66 vs. 4.29 ± 0.70) (p <.05). A blend of PCDEs may facilitate optimal career progression. Football academies should develop players' PCDEs, with a particular focus on developing their coping skills and their ability to realistically evaluate performances and work on weaknesses. [ABSTRACT FROM AUTHOR]

Purpose: The relative age effect (RAE) refers to the bias influence of birthdate distribution, with athletes born later in the selection year being under-represented in talent development systems. However, the 'underdog hypothesis' suggests that younger birth quarter (BQ) athletes are over-represented among those who successfully transition from youth systems to senior professional status. Methods: Accordingly, the purpose of this study was twofold; (1) to provide further test of the RAE over twelve seasons (n= 556), and (2) to examine the BQ of professional contracts awarded to academy graduates at an English professional football club over eleven seasons (n= 364). Results: Significantly skewed (P< 0.001) birthdate distributions were found for academy players (BQ1 n= 224: BQ2 n= 168; BQ3 n= 88; BQ4 n= 76). The distribution from academy graduates was also significantly skewed for professional contracts awarded (P= 0.03), with greater BQ4 representation (n= 8) compared to other BQs (BQ1 n= 5; BQ2 n= 8; BQ3 n= 6). Conclusion: These findings are indicative that the RAE continues to manifest within an academy setting. Interestingly however, the underdog hypothesis shows BQ4s were approximately four times more likely to achieve senior professional status compared to BQ1s. Implications for talent identification and development in football are discussed. [ABSTRACT FROM AUTHOR]

The main aim of the present study was to compare skeletal maturity level and physical capacities between male Norwegian soccer players playing at elite, sub‐elite and non‐elite level. Secondary, we aimed to investigate the association between skeletal maturity level and physical capacities. One hundred and two U14 soccer players (12.8‐14.5 years old) recruited from four local clubs, and a regional team were tested for bone age and physical capacities. Bone age was estimated with x‐ray of their left hand and used to indicate maturation of the skeleton. Players went through a comprehensive test battery to assess their physical capacities. Between‐groups analysis revealed no difference in chronological age, skeletal maturity level, leg strength, body weight, or stature. However, elite players were superior to sub‐elite and non‐elite players on important functional characteristics as intermittent‐endurance capacity (running distance: 1664 m ± 367 vs 1197 m ± 338 vs 693 m ± 235) and running speed (fastest 10 m split time: 1.27 seconds ± 0.06 vs 1.33 seconds ± 0.10 vs 1.39 seconds ± 0.11), in addition to maximal oxygen uptake (V˙O2max), standing long jump, and upper body strength (P <.05 for all comparisons). Medium‐to‐large correlations were found between skeletal maturity level and peak force (r = 695, P <.01), power (r = 684, P <.01), sprint (r = −.471, P<.001), and jump performance (r =.359, P <.01), but no correlation with upper body strength, V˙O2max, or intermittent‐endurance capacity. These findings imply that skeletal maturity level does not bias the selection of players, although well‐developed physical capacity clearly distinguishes competitive levels. The superior physical performance of the highest‐ranked players seems related to an appropriate training environment. [ABSTRACT FROM AUTHOR]

Effects of a 12-month complex proprioceptive-coordinative training program on soccer performance in prepubertal boys aged 10-11 years. J Strength Cond Res 33(5): 1380-1393, 2019-The aim was to examine the effects of a series of onfield proprioceptive-coordinative (P-C) exercises on motor performance (MP) in prepubertal soccer players. Fifty-three male soccer players aged 10.1 -11.8 years were randomized among 2 experimental programs receiving P-C training (P-CT; n = 26) or regular training (RT; n = 27). A control group (C; n = 22) consisted of age-matched (10.3-11.9 years) cohorts not involved in any regular physical activity. Both experimental groups completed an identical 1 2-month comprehensive soccer program except training in P-CT was modified to substitute small-sided conditioning games with 24 multimode P-C exercises with modulated exercise intensity (every 8 -9 weeks based on predicted maximal heart rate [HRmax]). Pre-, peri-, and posttraining measures included anthropometry and 5 tests assessing soccer-specific MP: movement rhythm (turning the ball backwards-T1), motor adaptation (running with the ball around poles-T2), spatial orientation (running to sequentially numbered balls-T3), balance (single-leg static balance-T4), and kinesthetic differentiation of movement (landing the ball on a 2 X 2 m sector-T5). Repeated-measures analysis of variance revealed no significance between-group differences for age, anthropometry, and body-fat percentage at baseline. Significant main effects for group (P-CT vs. RT) were found in all tests (T1-T5) and main effects for time (group P-CT) in T3- T5, whereas a significant group X time interaction was observed only in T4 (F = 2.98, p = 0.0204). Post hoc tests indicated that P-CT attained significantly better results than RT at peritraining (by 26.4%; p < 0.01) and posttraining (by 31.9%, p < 0.01). Modulated exercise intensity had little effect on soccer performance (T1-T3, T5). Based on the results, it is recommended that the training of young soccer players be supplemented with the bilateral balance exercises and games used in the study. Furthermore, the suitability of monitoring HR in P-C exercises targeting the analyzed MP skills is questionable. [ABSTRACT FROM AUTHOR]

Copyright of German Journal of Sports Medicine / Deutsche Zeitschrift fur Sportmedizin is the property of Verein zur Forderung der Sportmedizin Hannover e.V. and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

One common feature among the selected players in talent development programs are the wellknown relative age effect (RAE), characterized by a skewed birth distribution among selected players with an over-representation of players born early in the selection year. The aim of the present study was to examine the coaches and players' perceptions of soccer-specific skills between players selected for national talent program born in the first half of the year compared to the players born in the second half of the year. A total of 753 elite male U 14 (N = 363) and U 13 players (N = 390) from 16 of 18 soccer regions in Norway participated. The results showed that players born early in the selection year considered themselves stronger and faster than late born players. Similar, coaches considered the players born early in the selection year stronger than players born late in the selection year. Neither the players or coaches considered the early born players as technically, tactically and mentally better. Within a talent development program, we argue that coaches and recruiters should be aware of differences in relative age, and thus prevent that late born players must compensate their physical disadvantages to be allowed into such programs. [ABSTRACT FROM AUTHOR]