Are Soccer and Futsal Affected by the Relative Age Effect? The Portuguese Football Association Case

Abstract

A better understanding of the relative age effect (RAE) in youth will increase the awareness of the need for reducing the bias of (de)selection. Thus, we investigated the RAE in youth female and male soccer and futsal players in Portugal, using nationwide data. Birthdates of 5,306 female and 126,285 male soccer players, and 2,437 female and 23,988 male futsal players (U7–U19), registered in Portugal during the season 2019–2020, and Portuguese National teams (from U15 to AA soccer teams and from U17 to AA futsal teams) were analyzed. Data were categorized into age groups and certification levels [no certification, basic football training center, football school, and training institution] of the respective clubs/academies. Birthdates were stratified from the start of the selection year using quartiles (Q) and semesters (S). Differences between the observed and expected birthdate distributions were analyzed using chi-square statistics, and RAEs were calculated using odds ratios (OR). In both soccer and futsal, female players, in the age category U9, RAEs were found (Q1 vs. Q4, OR: 1.49 and 1.84, respectively). In male soccer, differences in the birthdate distribution were observed in all age categories (U7–U19) with significant OR between all comparisons (Q and S). In contrast, an over-representation of young male futsal players (Q1 vs. Q4) was observed only in the age categories U7 and U9 (OR: 1.54 and 1.34, respectively). The stratification by certification level showed a significant RAE for all certification levels in male soccer players. In contrast, in male futsal players, the RAE was significant only in clubs and academies with the highest level. For National teams, the RAE was more pronounced in male soccer, particularly in the U16 and U17 (OR: 9.84 and 12.36, respectively). Data showed a RAE in female and male youth soccer and futsal, particularly in male, younger age categories, and in clubs and academies having a higher certification level, which could be accompanied by a loss of valuable elite players during the youth phase of their careers. Thus, adjustments in the systems and structure of talent identification are recommended to prevent RAE-related discrimination in youth soccer and futsal.

Small Relative Age Effect Appears in Professional Female Italian Team Sports

“…In a male context, the magnitude of RAE is well documented, especially in sports where physical factors are fundamental for success [ 1 ] affecting a wide range of individual [ 6 , 11 , 12 , 15 ] and team sports from childhood to adulthood [ 14 , 16 , 17 , 18 , 19 , 20 ]. However, RAE may be influenced by sex differences.…”

Effects of Chronological Age, Relative Age, and Maturation Status on Accumulated Training Load and Perceived Exertion in Young Sub-Elite Football Players

“…Inconsistencies have been reported when seeking to understand the RAE in physical demands (Hill et al, 2020;Patel et al, 2020;Figueiredo et al, 2021). Patel et al (2020) reported that somatic maturity and anthropometric and physical performance characteristics distinguished retained or dropout individuals in an age group-dependent manner as opposed to birth quartile.…”

Relative Age Effect in Brazilian water polo: analysis of male and female athletes from U16 to senior categories

“…Joyner et al 14 suggest that the advantage generated during the selection and identification phases seems to disappear over time and may even be reversed in the transition to the elite sport. Indeed, the reduction of RAE as chronological age advances has been observed for several team sports in their respective countries 12,13 . Since the criteria for identifying talents and for the progressive development of the athlete may depend on the national or local culture and/or sports philosophy 15 , it is important to assess whether this relationship between age category and prevalence of RAE also occurs with sports of lesser popularity, as is the case of water polo in Brazil.…”

“…The constraints-based model 10 proposes that RAE existence and/ or dimension in the sports context is a consequence of the interaction of individual, environment, and task constraints. Regarding the individual's factors, the phase of the sports career seems to be a factor related to the existence of the RAE, since the magnitude of this effect tends to decrease as chronological age advances 11,12 . Bezuglov et al 13 showed that elite Russian soccer athletes from senior teams exhibited a less pronounced RAE compared to youth teams.…”