Longitudinal relative age effects in youth soccer and youth Gaelic football in Ireland

The purpose of the present study was to examine the presence and longitudinal trends of relative age effects (RAEs) in prominent Irish youth sports (soccer and Gaelic football) through a combination of cross-sectional, quasi-longitudinal, and longitudinal analyses. First, cross-sectional analyses of representative Irish youth soccer league squads (2015-2020) and youth Gaelic football inter-county development squads (2015-2020) in County Donegal, Ireland (N = 1519 athletes) confirmed the presence of RAEs across sport type and sex (2 [3, 1518] = 59.96, p < .001, w = .20). Quasi-longitudinal examination confirmed the trend that in soccer and Gaelic football, relatively older athletes were more likely to be selected to teams. Longitudinally, the most prominent RAE trends increased in boys Gaelic football as the athletes aged and the squad numbers reduced (OR range Q1 vs. Q4 = 1.41-2.50). Smaller increases were demonstrated within boys soccer over time. Although, soccer which has an earlier/younger age selection at U11 with a smaller roster size retention onto talent development pathways exacerbated the initial RAEs compared to Gaelic football which has a delayed/older age selection at U14 with a larger roster size retention onto talent development pathways