Relative Age Effect and its Differences Between Genders Among Chinese Youth Basketball Leagues

The primary aim of this study was to examine the presence and the magnitude of the relative age effect in Chinese youth basketball leagues. This study covered all athletes participating in the 2024 Chinese youth basketball league, including 64 male teams with 706 athletes and 48 female teams with 550 athletes. The chi-square test was used to determine the distribution of players' birth dates. Relative age team achievement (RATA) was utilized to quantify the team's overall birth date distribution. Competition statistics based on both per-game and per-minute indicators, together with player efficiency rating (PER) and win percentage, were employed to assess player and team performance. Spearman's correlation coefficient was utilized to calculate the relationship between birth date, age, and competition performance at both individual and team levels. The disparity in the distribution of athletes' birth dates was observed exclusively in the male cohort, whereas the disparity in the playing position was evident in both the male and female cohorts. Among men and women, the date of birth was associated with a total of 3 statistics of player performance. However, age has a positive effect on the 10 competition statistics for men and 7 competition statistics for women. The date of birth was not found to be statistically significant in relation to the performance of the team, whereas age demonstrated a positive correlation with the team's overall efficiency and win percentage. The findings demonstrated that the specific dimensions and magnitudes of the RAE in Chinese youth basketball leagues exhibited gender-specific variations. The prevalence of the RAE necessitates consideration by the Chinese Basketball Association, which should implement appropriate measures to mitigate potential inequities in youth sports.