Relative age effect in Spanish association football: its extent and implications for wasted potential

Spain is one of the largest and most successful powers in international youth football, but this success has not extended to the national team. This lack of continued success seems to indicate a loss of potential. The relative age effect has been detected in football in many countries. Understanding the extent of this bias in the youth teams of Spanish elite clubs may help to improve selection processes and reduce the waste of potential. Comparisons between players from: the Spanish Professional Football League, all age categories of these clubs' youth teams, the Under-17 to Under-21 national teams, the national team, and the Spanish population, show a constant tendency to under-represent players from the later months of the selection year at all age groups of youth and Under-17 to Under-21 national teams. Professional and national team players show a similar but diminished behaviour that weakens with ageing, which suggests that talent identification and selection processes can be improved to help better identify potential talent early on and minimize wasted potential.     

The relative age effect in a professional football club setting

Abstract

The relative age effect is an uneven distribution of birth date favouring subjects born in the initial months of a selection year. This study compared the birth-date distributions between several subgroups of Basque football players to identify whether the relative age effect is influenced by age and/or skill level. The study comprised 13,519 players including 114 senior professionals from the Spanish league's AC Bilbao over 21 seasons; over the season 2005–2006, it comprised elite youth (n = 189) from the same club's academy; regional youth (n = 4382) U11–U14 locally federated players; school youth (n = 8834) U10–U11 locally registered school district players. Differences between the observed and expected birth-date distributions were tested based on data from the general Basque male population. Significant chi-square values were followed up by calculating odds ratios and 95% confidence intervals (CI) for the quartile and half-year distributions to examine subgroup differences in the relative age effect. Birth-date distributions of all groups of players showed a significant bias towards early birth in the selection year compared with the reference population (senior, χ² ₃ = 24.4, P < 0.001; elite youth, χ² ₃ = 59.1, P < 0.001; regional youth, χ² ₃ = 41.4, P < 0.001; school youth, χ² ₃ = 40.9, P < 0.001). Between-group comparison revealed that the relative age effect incidence progressively increased with a higher level of involvement in youth football. This bias represents a significant loss of potential youth football talent.     

Women’s association football (soccer) in Brisbane,Queensland 1921–1933: new perspectives on early competition

ABSTRACT

In September 1921, two representative women’s teams played association football (soccer) on the Brisbane Cricket Ground in Queensland, Australia. The crowd size, approximately 10,000, was not commensurate with those attending matches featuring Dick, Kerr Ladies in England during the same period, but it was nonetheless a significant crowd at a match now widely acknowledged as Australia’s first public game of women’s association football. New evidence suggests it may have been the first between representative female association football sides, with players selected from local teams.

Contemporary accounts note the match as a single event. Regular organised competition did not occur until the early 1970s, but led to the formation of a national association in 1974. An overview of current literature and new archival research highlights the emergence of a strong culture around woman’s association football that begins before the Brisbane Cricket Ground match. The evidence presents a possible imbalance between what occurred and what has been recorded, and suggests a much more prolonged, if somewhat fragmented, engagement with association football between 1921 and 1933 in southern Queensland. The emergence of competition in Brisbane in the 1920s foregrounds the city’s – and, with it, Queensland’s – contribution to the history and development of Australian women’s football.     

Relative age effects in Swiss junior soccer and their relationship with playing position

Abstract

Relative age effects (RAEs) refer to age differences between children in the same selection year. The present study investigated the prevalence of RAEs and their link to playing positions in Swiss junior soccer. Swiss male junior soccer players (n=50,581) representing 11% of the age-matched population – members of extra-curricular soccer teams – were evaluated to determine the influence of RAEs on Swiss junior soccer. Subgroups were the national talent development programme (n=2880), and U-15 to U-21 national teams (n=630). While no RAEs were found for the self-selected extra-curricular soccer teams or for the U-20 teams (P>0.05), significant RAEs were found for talent development and the national U-15 to U-19 and U-21 teams (P<0.01). Additionally, defenders born early in the year were significantly overrepresented compared with goalkeepers, midfielders and strikers (P<0.05). In Switzerland, RAEs apparently have substantial influence on the talent identification process for U-15 to U-18 teams, significantly influencing the selection of players in talent development teams already at an early age, but do not influence self-selected participation in extra-curricular soccer. Additionally, the RAE bias may be a predictor of playing positions in national teams. To minimise RAEs in Swiss soccer, systematic education for all coaches regarding RAEs should be established, in addition to a slotting system with rotating calendar cut-off dates.     

西班牙足球发展回顾及崛起因素探骊

运用文献资料法等,对西班牙足球发展历程进行回顾与梳理,认为西班牙足球经历了历史发展的4个重要时期,即二战前的发轫时期（1945年前）、佛朗哥政治足球时期（1946年至1975年）、民主化时代的变革（1976年至2000年）、新千年后的崛起（2001年至今）。并且认为促成西班牙足球走向崛起的成功因素包括：文化层面,民族文化的独特性、多元性与碰撞性是西班牙走向“艺术足球”顶峰的内部核心动力;管理层面,民主化背景下足球管理体制、足球法制、利益分配机制的改革促使西班牙足球走向制度治理;人才层面,西班牙大众足球基础的夯实以及青少年足球训练体系的改革与科学化构建是西班牙足球走向崛起的人才保障。     

Defining the attributes for specific playing positions in football match-play: A complex systems approach

ABSTRACT

Introduction

Talent identification and development programmes that retain and develop athletes are integral to the sporting success of National Governing Bodies in football. Currently, player attributes are studied in isolation without considering the complexity of interacting components of football performance. The current study applied a systems analysis framework to describe, in a structured and systematic way, the attributes for specific playing positions in football match-play. Methods: Eight high-level football coaches were interviewed. Models of the interacting attributes were developed for each position using Work Domain Analysis (WDA). Results: Six WDA models detail the attributes associated with each playing position. The models identified purposes of playing positions (restrict opposition actions, organise and coordinate, building up of offence, goal scoring and stretch opposition), performance-related measures and the functions required to achieve the playing position purposes (game play, psychological functions, time and space and player actions). Critically, the relationships between the purposes, measures, functions, processes, and objects are described in the models.     

The relative age effect in soccer: A match-related perspective

Asymmetries in the distributions of birth dates in senior professional and youth soccer players have been interpreted as evidence for systematic discrimination against individuals born shortly before the cut-off date in assigning youth to specific age groups. This concept is known as the “relative age effect”. The results of a longitudinal study of birth date distritubions of 2757 semi-professional and amateur senior soccer players in Belgium are presented. Records for competitive games were available in official statistics provided by the Royal Belgian Football Association. The chi-square statistic was used to examine differences between observed and expected birth date distributions. Regression analyses indicated a shift of bias when two different start dates were compared. Players born in the early part of the new age band (January to March) were over-represented compared with players born late in the new selection period (October to December). However, players with birthdays at the start of the old selection year (August) were still represented. In a retrospective analysis of 2138 players, variables indicative of match involvement, number of selections for matches, and time played were examined in relation to the relative age effect. The group of semi-professional and amateur senior soccer players born in the first quarter of the selected age band received more playing opportunities. Comparisons of birth date distributions (traditional approach to relative age effect) with match-related variables gave similar, though not entirely consistent, results. However, there were no differences for the mean number of selections and for playing minutes between players born at the start or the end of the selection year. Our findings suggest that match-based variables may provide a more reliable indication of the relative age effect in soccer.     

Hill on a mountaintop: A longitudinal and cross-sectional analysis of the relative age effect in competitive youth football

ABSTRACT

The aim of this study was to examine the origin and persistence of the relative age effect (RAE) in competitive youth football. To examine its origin, birthdates of 121 category one Premier League academy players recruited over 6 years were compared with 691 Under 8 (U8) players in one of the regional grassroots leagues from which academy players are selected. To examine the persistence of the RAE we conducted a longitudinal comparison of retention rates in early-birth and late-birth academy players from U9 to U15, and made a cross-sectional comparison of birthdate distributions from U7 to U18 in 10,857 regional league players. The results revealed birthdate asymmetry in both the academy and grassroots players but a much larger RAE in the academy. Longitudinal analysis revealed that the cumulative probability of retention at the academy was higher for early-birth than late-birth players. A small to medium RAE persisted across grassroots football age groups though it declined somewhat from U15 to U18. The implication of these results for academy player recruitment is discussed.     

Performance analysis in football: A critical review and implications for future research

Abstract

This paper critically reviews existing literature relating to performance analysis (PA) in football, arguing that an alternative approach is warranted. The paper considers the applicability of variables analysed along with research findings in the context of their implications for professional practice. This includes a review of methodological approaches commonly adopted throughout PA research, including a consideration of the nature and size of the samples used in relation to generalisability. Definitions and classifications of variables used within performance analysis are discussed in the context of reliability and validity. The contribution of PA findings to the field is reviewed. The review identifies an overemphasis on researching predictive and performance controlling variables. A different approach is proposed that works with and from performance analysis information to develop research investigating athlete and coach learning, thus adding to applied practice. Future research should pay attention to the social and cultural influences that impact PA delivery and athlete learning in applied settings.     

Identifying talented track and field athletes: The impact of relative age effect on selection to the Spanish National Athletics Federation training camps

This study examined the impact of relative age effect (RAE) on selection to the Spanish National Athletics Federation (RFEA) training camps (TC) between 2006 and 2013. Overall, 1,334 selected athletes at U15 years (cadet) and U17 years (juvenile) were compared against 27,711 licensed but unselected athletes for the same age groups. The results highlighted the influential role of the RAE on selection to national level track and field training camp opportunities. Interestingly, this effect was mediated by age and gender, where effects were stronger for both males and younger athletes (U15), with no evidence of RAE for older (U17) female athletes. These results support the “maturation-selection” hypothesis as a mechanism for RAE. Particularly given the long-term goals of RFEA (e.g., production of successful senior elite athletes), these results highlight the need to consider the impact of current selection processes on effective provision of opportunities to those athletes with most potential to succeed in the long term. A number of possible context-relevant solutions are discussed, including education and awareness raising, using holistic selection criteria and correction adjustments techniques.     

The relative age effect in the German Football TID Programme: Biases in motor performance diagnostics and effects on single motor abilities and skills in groups of selected players

Abstract

This study examined the disturbing effects of relative age on the talent identification process in the talent development programme of the German Football Association. The bias in the selection rate was examined via the extent of relative age effects. The bias in motor performance diagnostics was analysed by comparing the motor performance of selected players with normal motor development. The mechanisms underlying the relative age biases in motor performance were examined by modelling the direct and indirect effects of relative age on single motor performance tests for sprint, running agility, dribbling and ball passing and control. Data from 10,130 selected football players from the U12 to U15 age groups were collected in autumn 2010. The birth distribution differed significantly from the reference population with approximately 61% of the players born in the first half of the year. The selection probability was approximately two times higher for players born in the first quarter of the year than for players born in the last quarter. Revised motor performance diagnostics showed better results on average for relatively younger players. Path analysis revealed significant direct and indirect relative age effects for physiologically demanding tests and almost no effects for technically demanding tests. Large sample sizes allowed high resolution in relative age with additional informational content and multivariate modelling of the complex relationships among relative age, physical development and motor performance. The results are discussed on how relative age affects the effectiveness and fairness of talent identification and development processes.