Do Biological Maturity and Motor Performance Influence Perceived Player Quality? Evidence from U-15 Soccer Players

This study had two primary objectives: first, to examine the influence of biological maturity status and motor performance indicators on coach-assessed player quality in U-15 soccer players; and second, to explore differences in estimated biological age between players of different quality levels. A secondary objective was to identify differences in morphological characteristics and motor performance between players belonging to different bio-banded maturity groups. A total of 240 U-15 male players (14.12 ± 0.84 years) were assessed for estimated biological age (Mirwald method), motor performance (speed and agility tests with and without ball), and perceived quality (5-point scale). Ordinal regression showed that biological age (OR = 2.47) and slalom performance with and without ball, as well as the 20 m sprint with ball, significantly predicted quality, whereas chronological age had a negative effect (OR = 0.44). Biological age differed significantly across quality groups (F = 3.65, p = 0.007, η² = 0.06), remaining significant after controlling for chronological age (F = 3.78, p = 0.005). Bio-banded groups differed significantly in morphological characteristics and in 20 m sprint performance with and without ball, but most differences were attenuated after adjusting for chronological age. These findings confirm the role of biological maturity in coaches' perception of player quality, with agility tests appearing less maturity-biased than speed tests, while highlighting ball-oriented performance as a potential predictor of playing success.