The efficacy of talent selection criteria in the Australian Football League

ABSTRACT

This study investigated the association between talent selection criteria, draft order and match performance in professional Australian Football players. Physical performance results from the Australian Football League (AFL) National Draft combine and non-performance based talent selection criteria were collated for all players drafted in the National Draft with selections 1–80 between 2003 and 2008 (n = 318). Match performance was assessed via the AFL Player Ranking metric that was provided by a commercial statistical provider (Champion Data Pty Ltd). A combination of stepwise multiple regression and linear mixed model analyses examined the influence of National Draft combine physical performance assessments and non-performance based talent selection criteria on draft order and future match performance. Earlier draft selection was associated with Under-18 all Australian team selection, height, Under-18 National Championship participation and indigenous status. The 20 m sprint and state of origin were associated with later draft selection. Under-18 all Australian team selection increased both Player Ranking/game and total Player Ranking. Under-18 all Australian team selection displays efficacy for selecting players with the potential for success.     

Home advantage in the Australian Football League

The results of this study on home advantage in Australian rules football demonstrate that individual clubs have different home advantages. Traditional measures of home advantage as applied to whole competitions such as percentage of games won, and alternative measures such as average margin of victory for the home team, are calculated. Problems with these measures are discussed. Individual home advantages for each team are obtained using a linear model fitted to individual match margins; the resultant home advantages are analysed, and variations and possible causes or groupings of home advantage are proposed. It is shown that some models allowing different home advantages for different clubs are a significant improvement over previous models assuming a common home advantage. The results show a strong isolation effect, with non-Victorian teams having large home advantages, and lend support to the conclusion that crowd effects and ground familiarity are a major determinant of home advantage.     

全民健身国家战略视阈下我国城市足球联赛的可持续发展研究

以文献资料法为主要研究方法,对我国城市足球联赛开展的背景、我国城市足球联赛发展过程中存在的主要问题以及可持续性发展进行了研究.研究发现:我国城市足球联赛中存在管理体制不健全、裁判员执法水平不高以及缺乏与校园足球的互动等主要问题.提出:完善城市足球联赛管理体制;加强城市足球联赛商业开发,扩大赛事影响力;加强与校园足球的互动;充分发挥城市足球联赛在全民健身中的作用等相关对策.     

Relative age and maturation selection biases in academy football

ABSTRACT

This study examined the simultaneous effects of relative age and biological maturity status upon player selection in an English professional soccer academy. A total of 202 players from the U9 to U16 age groups, over an eight-year period (total of 566 observations), had their relative age (birth quarter) and biological maturity (categorised as late, on-time or early maturing based upon the Khamis-Roche method of percentage of predicted adult height at time of observation) recorded. Players born in the first birth quarter of the year (54.8%) were over-represented across all age groups. A selection bias towards players advanced in maturity status for chronological age emerged in U12 players and increased with age; 0% of players in the U15 and U16 age group were categorised as late maturing. A clear maturity selection bias for early maturing players was, however, only apparent when the least conservative criterion for estimating maturity status was applied (53.8% early and 1.9% late maturing in the U16 age group). Professional football academies need to recognise relative age and maturation as independent constructs that exist and operate independently. Thus, separate strategies should perhaps be designed to address the respective selection biases, to better identify, retain and develop players.     

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.     

Relative age effect: implications for effective practice

Physical and psychological differences related to birthdate amongst athletes of the same selection year have been characterised as the “relative age effects” (RAEs). RAEs have been identified in a variety of sports, both at youth and adult level, and are linked with dropout of athletes and a reduction of the talent pool. This study examined the existence, mechanisms and possible solutions to RAEs using qualitative methodology. Seven experts in the field of talent identification and development were interviewed. Inductive analysis of the data showed that, while there was mixed evidence for the existence of RAEs across sports, the eradication of RAEs was attributed to controllable features of the development environment. The factors reported included the structure of “categories” used to group athletes within the sport (e.g. age, weight, size, skills), recognition and prioritisation of long-term development over “short term win focus.” Education of relevant parties (e.g. coaches, scouts, clubs) about RAEs and the nature of “talent” within a long-term context was suggested, along with careful consideration of the structure of the development environment (e.g. delayed selection, provision for late developers, focus on skills not results, use of challenge). Implications for research and practice are discussed.     

Performance Differences between National Football League and High School American Football Combine Participants

Purpose: The purpose of this study was to determine magnitudes of differences for anthropometric and athletic performance scores between high school and elite college-level American football players. Method: Participants included high school-age (n = 3,666) athletes who participated in American football combines, as well as elite college-level (n = 5,537) athletes who participated in the National Football League (NFL) scouting combine. Combine data included position; height; weight; 10-, 20-, and 40-yard dash; pro-agility (PA); L-cone drill (LC); vertical jump (VJ); and broad jump (BJ). Athletes were separated into their respective position group, defensive back (DB), wide receiver (WR), linebacker (LB), quarterback (QB), running back (RB), tight end (TE), defensive line (DL), and offensive line (OL) for analysis of performance differences. Percent differences for each dependent variable were calculated to quantify magnitudes of differences. Results: NFL combine participants scored 3% to 25% better on all measurements, with the largest differences between weight and VJ (14%–25%). Conclusion: The largest measurement-specific differences between high school-age and elite college-level American football players were body size and power. Although it may seem intuitive that elite college-level players would perform better, these data provide a unique perspective to high school players, parents, and coaches, giving new information to use when designing measurement-specific athletic development programs. Thus, strength and conditioning professionals may benefit from emphasizing increases in muscle mass and power output in strength and conditioning programs.     

The use of player physical and technical skill match activity profiles to predict position in the Australian Football League draft

This study investigated the extent to which position in the Australian Football League (AFL) national draft is associated with individual game performance metrics. Physical/technical skill performance metrics were collated from all participants in the 2014 national under 18 (U18) championships (18 games) drafted into the AFL (n = 65; 17.8 ± 0.5 y); 232 observations. Players were subdivided into draft position (ranked 1–65) and then draft round (1–4). Here, earlier draft selection (i.e., closer to 1) reflects a more desirable player. Microtechnology and a commercial provider facilitated the quantification of individual game performance metrics (n = 16). Linear mixed models were fitted to data, modelling the extent to which draft position was associated with these metrics. Draft position in the first/second round was negatively associated with “contested possessions” and “contested marks”, respectively. Physical performance metrics were positively associated with draft position in these rounds. Correlations weakened for the third/fourth rounds. Contested possessions/marks were associated with an earlier draft selection. Physical performance metrics were associated with a later draft selection. Recruiters change the type of U18 player they draft as the selection pool reduces. juniors with contested skill appear prioritised.     

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.     

Evolution of game-play in the Australian Football League from 2001 to 2015

This study investigated the evolution of game-play manifested via team performance indicator characteristics in the Australian Football League (AFL) from the 2001 to 2015 seasons. The mean values for 18 performance indicators were collated for every AFL team over 15-seasons. A multivariate analysis was used to uncover temporal trends in the dataset. Compared to the 2004 season, the 2005 to 2010 seasons were characterised by large growth in the counts of handballs (d = 0.83; 90% CI = 0.22–1.43), disposals (d = 1.24; 90% CI = 0.59–1.87), uncontested possessions (d = 1.37; 90% CI = 0.71–2.01), clangers (d = 2.14; 90% CI = 1.39–2.86) and marks (d = 1.43; 90% CI = 0.76–2.07). Contrastingly, the effective disposal percentage declined rapidly during the same period. The number of inside 50 m counts remained stable throughout the 15-season period. The ordination plot of league-wide performance indicator characteristics illustrated a distinct cluster from the 2001 to 2004 seasons, an abrupt shift from the 2005 to 2009 seasons, and an emergent (re)stabilisation from the 2010 to 2015 seasons. The results demonstrate the synchronous league-wide evolution of game-play in the AFL from the 2001 to 2015 seasons. Amongst other constituents, this evolution likely reflects the introduction of modernised coaching strategies, rule changes and changing perceptions of rule interpretations.     

全国少年足球联赛射门特点分析

通过对１９９５年全国少年足球联赛延吉赛区参赛队射门特点与规律的统计分析，发现边路进攻传中射门是最有效的得分手段；利用远射来达到玻门得分的目的，是这次比赛中又一新的特点，反映出少年运动页积极的进攻意识和强烈的射门欲望。同时，头顶球射门得分在比赛中得以充分体现，因而身高应是选材重要指标之一．     

澳大利亚澳式足球联盟发展沿革

本文分析了澳式足球联盟发展及其体育卡特尔特质,指出：澳式足球联盟是各俱乐部联合起来组成的一种现代企业集团,通过极具策略的开发其卡特尔特质,加强垄断力量,在管理机制、联盟构成、竞赛平衡、成本控制、竞赛质量等方面进行改革,实行行业垄断,不断扩大市场,促使利润最大化并使各俱乐部分享联合利润。     

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.     

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

Abstract

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.     

A bioecological perspective on talent identification in junior-elite soccer: A Pan-European perspective

ABSTRACT

Elite soccer clubs across Europe spend ever-increasing sums of money on transfers and salaries for world-class players. Consequently, clubs’ talent identification and development processes for junior players have become more professionalised. Based on a holistic ecological approach, this study presents an analysis of talent identification practices across some of the most productive soccer academies in Europe (N = 11). Data were collected via semi-structured interviews with 11 heads of academy recruitment from clubs in the “big five” European leagues. Clubs were purposively sampled based on their player productivity ranking. Interviews ranged from 52:26 minutes to 114:06 minutes in length (m = 87:53 ± 20.10 minutes). This study argues that holistic ecological approaches the environments were characterised through the interplay of factors that ranged from high-level internal to international level relationships. This resulted in the identification and recruitment of players from local and international environments. The purpose of recruitment was suggested to have a dual purpose: recruitment of players for the first team; recruitment of players for further development/monitoring and/or selling to another club.     

Faster,higher, stronger,older: Relative age effects are most influential during the youngest age grade of track and field athletics in the United Kingdom

The relative age effect (RAE) is a common phenomenon in youth sport, whereby children born early in the selection year are more likely to experience success and to sustain participation. There is a lack of research investigating variables which influence RAEs within track and field athletics. Such information is vital to guide policies in relation to competition structure, youth development squads and coach education. A database of competition results was analysed to determine the extent to which RAEs were present in track and field athletics in the United Kingdom. Subsequent analyses examined whether age, sex, event and skill level influenced the RAE. Examination of 77,571 records revealed that RAEs were widespread, but most pronounced during Under 13 (U13) competitions; that is, during athletes’ first exposure to formal track and field competition. Sex, event and skill level further influenced the existence and magnitude of RAEs at different age grades. Relative age is a key influencing factor within track and field athletics, especially at the youngest age category. Consequently, national governing bodies need to consider what administrative and stakeholder initiatives are necessary to minimise the effects of RAEs on young athletes’ early experiences of competition.     

Asymmetries in scheduling slots and game-day revenues: An example from the Australian Football League

This article investigates three related questions: first, whether the Australian Football League exhibits attendance asymmetries across the available playing slots; second, whether various subgroups of teams in the AFL have equal access to the more highly attended time slots; and, third, whether asymmetries in the first two phenomena can drive meaningful asymmetries in match-day revenues across clubs. We find that asymmetries exist not only across the various playing slots, but also in various teams’ access to the more highly attended slots. Further, by providing some novel estimates of revenue streams from television and gate receipts, we show that these asymmetries can drive substantial differences in game-day revenues. A key implication is that scheduling should be treated with the same critical analysis as the many other factors that affect the financial performance of clubs.     

2005年全国女子足球联赛队伍现状调查研究

运用文献资料调研和调查访谈方法,对参加2005年全国女子足球联赛的9支队伍进行研究。研究认为,参加女子足球联赛的队伍中存在训练和比赛经费不足、运动员力量和拼抢训练缺乏、教练员的选拔及培养有待加强、运动员出路应被重视等问题,并提出相关建议。     

National Football League head coach race,performance, retention,and dismissal

The authors tested for evidence of racial discrimination in the employment retention of National Football League head coaches. A robust data set spanning the modern history of the sport (1985–2018) was generated to examine managerial employment tenure, dismissal, and subsequent organizational performance. After controlling for performance differences and heterogeneity between head coaches, the authors uncover statistically significant evidence that Non-White head coaches experience longer employment spells relative to White head coaches in the Rooney Rule era. No statistically significant evidence of racial differences in the rate at which head coaches are fired is found. Both employment tenure and dismissal are largely driven by raw performance, and to a lesser degree, relative performance. Finally, the relationship between head coach race and organizational performance is examined, but no statistically significant differences by race are uncovered.     

相对年龄影响足球运动员选材制度调控策略的研究——兼述对我国青少年儿童足球运动员选材制度改革的启示

通过文献分析和实证研究等方法分析相对年龄对青少年儿童足球运动员选材制度产生的负面影响,并从当前训练和竞赛的分组入选制度方面进行研究.研究认为,改革基于日历年龄的分组入选制度、采用基于生物年龄的分组入选制度、采用多重标准的分组入选制度,可提高青少年儿童足球运动员选材的成功率.