Biological maturation, relative age and self-regulation in male professional academy soccer players: A test of the underdog hypothesis

Objectives The main and interactive effects of biological maturity status and relative age upon self-regulation in male academy soccer players are considered. Consistent with the ‘underdog’ hypothesis, whereby relatively younger players may benefit from competitive play with older peers, it was predicted later maturing and/or relatively younger players would report more adaptive self-regulation. Design Cross-sectional study. Method Players (n = 171, aged 11–16 years) from four English professional soccer academies completed the modified Soccer Self-Regulation Scale. Date of birth, height, weight and parental height were obtained. Relative age was based on birth quarter for the selection year. Maturity status was based upon percentage of predicted adult height attained. Results Linear regression models showed later maturation was inversely associated with adaptive self-regulation, while relative age was unrelated to self-regulation. Conclusions In partial support of the underdog hypothesis, later maturing players appear to possess a psychological advantage.