A professional English football club with Category 1 academy status was investigated to determine the magnitude of relative age effects (RAE) within the club and explore between-quartile differences for somatic maturity, anthropometry and physical performances. Birth dates of 426 players from Under 9 to First Team were categorised into four birth quartiles (Q) and examined for relative age effects. Additionally, data on 382 players (Under 11 to First Team) were obtained for somatic maturity, anthropometry, countermovement jump, sprint (10 and 30 m), agility T-test and Yo-Yo Intermittent Recovery Level 1 or 2 performance to determine between-quartile differences. Odds ratios revealed Q1 players were 6.0 times more likely to be represented than Q4 players. Multilevel modelling demonstrated between birth quartile similarities for each variable across all age groups, though there was a tendency for Q4 players to outperform Q1 players between Under 11 and Under 18 groups. Strong relative age effects exist within this club as well as a tendency to select players demonstrating advanced growth and/or maturity, with some indication that higher categorised academies in England may be at risk of amplified selection biases. Talent identification strategies in elite youth football should actively seek to adopt novel approaches to reduce selection biases and avoid wasted potential.
Premier League. Elite player performance plan. Premier League, Gloucester Place, London, England, May 2011.
4.
WilliamsAMReillyT. Talent identification and development in soccer. J Sports Sci2000; 18: 657–667.
5.
SarmentoHAngueraMTPereiraA, et al.Talent identification and development in male football: a systematic review. Sports Med2018; 48: 907–931.
6.
SimmonsCPaullGC. Season-of-birth bias in association football. J Sports Sci2001; 19: 677–686.
7.
MujikaIVaeyensRMatthysSPJ, et al.The relative age effect in a professional football club setting. J Sports Sci2009; 27: 1153–1158.
8.
Sierra-DiazMJGonzalez-VilloraSPastor-VicedoJC, et al.Soccer and relative age effect: a walk among elite players and young players. Sports (Basel)2017; 5: 5.
9.
LovellRTowlsonCParkinG, et al.Soccer player characteristics in English lower-league development programmes: the relationships between relative age, maturation, anthropometry and physical fitness. PloS One2015; 10: e0137238.
10.
MüllerLGehmaierJGonausC, et al.Maturity status strongly influences the relative age effect in International Elite Under-9 Soccer. J Sports Sci Med2018; 17: 216–222.
11.
CobleySBakerJWattieN, et al.Annual age-grouping and athlete development. Sports Med2009; 39: 235–256.
12.
DeprezDCouttsAJFransenJ, et al.Relative age, biological maturation and anaerobic characteristics in elite youth soccer players. Int J Sports Med2013; 34: 897–903.
13.
HiroseN. Relationships among birth-month distribution, skeletal age and anthropometric characteristics in adolescent elite soccer players. J Sports Sci2009; 27: 1159–1166.
14.
MullerLGonausCPernerC, et al.Maturity status influences the relative age effect in national top level youth alpine ski racing and soccer. PloS One2017; 12: e0181810.
15.
JohnsonAFarooqAWhiteleyR. Skeletal maturation status is more strongly associated with academy selection than birth quarter. Sci Med Footb2017; 1: 157–163.
16.
BrewerJBalsomPDavisJ. Seasonal birth distribution amongst European soccer players. Sports Exerc Inj1995; 1(3): 154–157.
17.
Gutiérrez-Díaz del CampoDPastor-VicedoJCGonzález-VilloraS, et al.The relative age effect in youth soccer players from Spain. J Sports Sci Med2010; 9: 190–198.
18.
HelsenWFVan WinckelJWilliamsAM. The relative age effect in youth soccer across Europe. J Sports Sci2005; 23: 629–636.
19.
SkorskiSSkorskiSFaudeO, et al.The relative age effect in German Elite Youth Soccer: implications for a successful career. Int J Sports Physiol Perform2015; 11: 370–376.
20.
Pérez-JimenezIPainMTG. Relative age effect in Spanish association football: its extent and implications for wasted potential. J Sports Sci2008; 26(10): 995–1003.
21.
CarlingCle GallFReillyT, et al.Do anthropometric and fitness characteristics vary according to birth date distribution in elite youth academy soccer players?Scand J Med Sci Sports2009; 19: 3–9.
22.
DeprezDVaeyensRCouttsAJ, et al.Relative age effect and Yo-Yo IR1 in youth soccer. Int J Sports Med2012; 33: 987.
23.
FragosoIMassucaLMFerreiraJ. Effect of birth month on physical fitness of Soccer players (Under-15) according to biological maturity. Int J Sports Med2015; 36(1): 16–21.
24.
WattieNSchorerJBakerJ. The relative age effect in sport: a developmental systems model. Sports Med2015; 45(1): 83–94.
25.
LloydRSOliverJLFaigenbaumAD, et al.Chronological age vs. biological maturation: implications for exercise programming in youth. J Strength Cond Res2014; 28(5): 1454–1464.
26.
Stewart A, Marfell-Jones M, Olds T, et al. International standards for anthropometric assessment ISAK: The International Society for the Advancement of Kinanthropometry, Lower Hutt, New Zealand, 2011.
27.
SemenickD. Tests and Measurements: The T-test. Strength Cond J1990; 12: 36–37.
28.
KrustrupPMohrMAmstrupT, et al.The Yo-Yo intermittent recovery test: physiological response, reliability, and validity. Med Sci Sports Exerc2003; 35: 697–705.
29.
KrustrupPMohrMNyboL, et al.The Yo-Yo IR2 test: physiological response, reliability, and application to elite soccer. Med Sci Sports Exerc2006; 38: 1666–1673.
30.
MirwaldRLBaxter-JonesADBaileyDA, et al.An assessment of maturity from anthropometric measurements. Med Sci Sports Exerc2002; 34: 689–694.
31.
DelormeNBoichéJRaspaudM. Relative age effect in elite sports: methodological bias or real discrimination?Eur J Sport Sci2010; 10: 91–96.
32.
HelsenWFBakerJMichielsS, et al.The relative age effect in European professional soccer: did ten years of research make any difference?J Sports Sci2012; 30: 1665–1671.
33.
MalinaRMRogolADCummingSP, et al.Biological maturation of youth athletes: assessment and implications. Br J Sports Med2015; 49: 852–859.
34.
MalinaRMCoelhoESMJFigueiredoAJ, et al.Interrelationships among invasive and non-invasive indicators of biological maturation in adolescent male soccer players. J Sports Sci2012; 30(15): 1705–1717.
35.
MillsKBakerDPaceyV, et al.What is the most accurate and reliable methodological approach for predicting peak height velocity in adolescents? A systematic review. J Sci Med Sport2017; 20: 572–577.
SherarLBBaxter-JonesADFaulknerRA, et al.Do physical maturity and birth date predict talent in male youth ice hockey players?J Sports Sci2007; 25: 879–886.
38.
FurleyPMemmertD. Coaches’ implicit associations between size and giftedness: implications for the relative age effect. J Sports Sci2016; 34: 459–466.
39.
CarlingCLe GallFMalinaRM. Body size, skeletal maturity, and functional characteristics of elite academy soccer players on entry between 1992 and 2003. J Sports Sci2012; 30: 1683–1693.
40.
GibbsBGJarvisJADufurMJ. The rise of the underdog? The relative age effect reversal among Canadian-born NHL hockey players: a reply to Nolan and Howell. Int Rev Sociol Sport2012; 47: 644–649.
41.
McCarthyNCollinsD. Initial identification & selection bias versus the eventual confirmation of talent: evidence for the benefits of a rocky road?J Sports Sci2014; 32: 1604–1610.
42.
CummingSPSearleCHemsleyJK, et al.Biological maturation, relative age and self-regulation in male professional academy soccer players: a test of the underdog hypothesis. Psychol Sport Exerc2018; 39: 147–153.
43.
WrigleyRDDrustBStrattonG, et al.Long-term soccer-specific training enhances the rate of physical development of academy soccer players independent of maturation status. Int J Sports Med2014; 35: 1090–1094.
44.
DeprezDValente-Dos-SantosJCoelhoESMJ, et al.Longitudinal development of explosive leg power from childhood to adulthood in Soccer players. Int J Sports Med2015; 36: 672–679.
45.
DeprezDNFransenJLenoirM, et al.A retrospective study on anthropometrical, physical fitness, and motor coordination characteristics that influence dropout, contract status, and first-team playing time in high-level soccer players aged eight to eighteen years. J Strength Cond Res2015; 29: 1692–1704.
46.
HelsenWFStarkesJLVan WinckelJ. The influence of relative age on success and dropout in male soccer players. Am J Human Biol1998; 10: 791–798.
47.
HillBSotiriadouP. Coach decision-making and the relative age effect on talent selection in football. Eur Sport Manag Q2016; 16: 292–315.
48.
BuchheitMMendez-VillanuevaA. Reliability and stability of anthropometric and performance measures in highly-trained young soccer players: effect of age and maturation. J Sports Sci2013; 31: 1332–1343.
49.
MannDLvan GinnekenPJ. Age-ordered shirt numbering reduces the selection bias associated with the relative age effect. J Sports Sci2017; 35: 784–790.
50.
CummingSPLloydRSOliverJL, et al.Bio-banding in sport: applications to competition, talent identification, and strength and conditioning of youth athletes. Strength Cond J2017; 39: 34–47.
