The influence of maturation on the balance and change-of-direction asymmetry characteristics in trained youth male soccer players

This study investigated inter-limb differences in static balance, dynamic balance, and change-of-direction (COD) performance, and assessed the influence of biological maturation on the corresponding asymmetry characteristics in trained youth male soccer players. Seventy-five national-level players completed assessments using the Balance Error Scoring System (BESS), Y Balance Test, and Arrowhead Agility Test for COD. The dominant limb exhibited significantly fewer errors in the overall BESS score (Diff: −5.97 errors; 95% CI: −6.97 to − 4.98), greater normalized reach distances in the Y Balance Test composite score (Diff: 3.33%; 95% CI: 2.83 to 3.83), and faster change-of-direction performance (Diff: −0.22 s; 95% CI: −0.27 to − 0.16) than the non-dominant or less-skillful side ( p < 0.001 for all). Centered maturity offset significantly predicted all balance and COD asymmetry outcomes, explaining 15–62% of the variance ( p ≤ 0.001). Moderation analyses further showed that asymmetry magnitudes progressively decreased with advancing biological maturity across all balance and COD outcomes. These findings suggest that maturation influences inter-limb asymmetries in neuromuscular performance, highlighting the importance of considering biological maturity for accurate performance profiling and individualized training in youth soccer players.