Effect of Relative Age on Physical Size and Motor Ability Among Japanese Elementary Schoolchildren

Abstract

A child born soon after the designated cut-off date (“early-born”) may benefit by up to a full year in physical and psychological development, unlike one born just before the cut-off date (“late-born”). This phenomenon—called the “relative age effect”—causes inequalities in education and impacts the psychological aspects of children’s sports participation. However, its influence on physical aspects has not been clarified. Therefore, we examined its impact on physical size and motor ability among Japanese elementary schoolchildren (384 males and 360 females). We collected demographic data and measured physical size and motor abilities. Analysis of covariance showed that early-born children scored significantly higher than late-born children across variables, indicating the effect of relative age on physical aspects of sports participation and the possible advantage of early-born over late-born children in sports achievement. We propose the need for acknowledging this phenomenon in educational settings among teachers and coaches.