Sports Medicine

, Volume 39, Issue 3, pp 235–256 | Cite as

Annual Age-Grouping and Athlete Development

A Meta-Analytical Review of Relative Age Effects in Sport
  • Stephen CobleyEmail author
  • Joseph Baker
  • Nick Wattie
  • Jim McKenna
Review Article


Annual age-grouping is a common organizational strategy in sport. However, such a strategy appears to promote relative age effects (RAEs). RAEs refer both to the immediate participation and long-term attainment constraints in sport, occurring as a result of chronological age and associated physical (e.g. height) differences as well as selection practices in annual age-grouped cohorts. This article represents the first meta-analytical review of RAEs, aimed to collectively determine (i) the overall prevalence and strength of RAEs across and within sports, and (ii) identify moderator variables. A total of 38 studies, spanning 1984–2007, containing 253 independent samples across 14 sports and 16 countries were re-examined and included in a single analysis using odds ratios and random effects procedures for combining study estimates. Overall results identified consistent prevalence of RAEs, but with small effect sizes. Effect size increased linearly with relative age differences. Follow-up analyses identified age category, skill level and sport context as moderators of RAE magnitude. Sports context involving adolescent (aged 15–18 years) males, at the representative (i.e. regional and national) level in highly popular sports appear most at risk to RAE inequalities. Researchers need to understand the mechanisms by which RAEs magnify and subside, as well as confirm whether RAEs exist in female and more culturally diverse contexts. To reduce and eliminate this social inequality from influencing athletes’ experiences, especially within developmental periods, direct policy, organizational and practitioner intervention is required.


Skill Level Young Athlete Sport Participant Youth Sport Sport Context 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.



No funding was received for this review, and the authors have no conflicts of interest that are directly relevant to the content of this review.


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Copyright information

© Springer International Publishing AG 2009

Authors and Affiliations

  • Stephen Cobley
    • 1
    Email author
  • Joseph Baker
    • 2
  • Nick Wattie
    • 1
  • Jim McKenna
    • 1
  1. 1.Leeds Metropolitan UniversityLeeds Metropolitan UniversityLeedsUK
  2. 2.School of Kinesiology and Health ScienceYork UniversityTorontoCanada

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