Evolution of the relative age effect in spanish young footballers (U8 to U19). A comparative analysis in elite clubs vs. low-level clubs.

Abstract

The purpose of this study was to identify the existence of Relative Age Effect (RAE) at youth football level in Elite and lower-level clubs in Spain.  RAE was also analyzed within each age group of players (U8 to U19) and within each team category considering the sport expertise level (A, B, C and D teams), according to the kind of club. All players (n = 1862) belonged to eight Spanish football clubs and 114 teams. Birth dates were categorized into relative age quartiles. The results obtained by the square test revealed the existence of a RAE with a large effect in the Elite group, while in the lower-level group this effect was medium. Thus, results show significant differences in the Elite group in all age categories, whilst in the lower-level group these were only observed in the U14, U16 and U18 categories. With respect to the team category, while RAE was observed in the Elite group in all teams, in the lower-level group it was only observed in teams A and B. In conclusion, RAE is more pronounced in Elite clubs, even starting at the U8 category. However, in lower-level clubs, where the objective is not just performance, it is delayed.