Selection time and differences in biological maturity of soccer players in Japan Professional Football League Academy

Abstract

In the present study, we examined the biological maturity of young Japanese football players. In Japan’s football training system, players are selected at a young age. However, relatively early maturing players might be selected if the selection is based solely on technical and physical fitness factors. To eliminate this drawback in player selection, we believe that it is necessary to determine the players’ biological maturity accurately. Accordingly, the present study aimed to investigate the biological maturity of football players during the selection process. We included 475 young Japanese football players (mean age: 12.4 ± 0.6 years) affiliated with the Japan Professional Football League between 2007 and 2015. According to an unpaired t-test, there was no significant difference between the Tanner-Whitehouse 2 (Japan) skeletal age and the chronological age of the affiliated players. The difference in biological maturity between the junior youth (Jy) group (mean age: 12.9 ± 0.4 years [12.0–13.9]) and the junior (Jr) group (mean age: 11.8 ± 0.3 years [11.0–12.4]) was examined using a chi-squared test. The results of the residual analysis revealed a significant difference between the Jy and Jr groups ( χ 2 = 22.552, degree of freedom = 3, p < 0.01). We evaluated the biological maturity of young football players and examined the relationship between the differences in maturity and the timing of player selection. In the player selection process in this study, it was speculated that early maturing players may not always be easy to identify.