Effects of a combined non-dominant-limb-focused technical and unstable-surface balance training program on dynamic postural control, inter-limb asymmetry, and soccer-specific performance in young soccer players

Background Soccer involves frequent unilateral and bilateral actions that may contribute to differences between dominant and non-dominant limbs. Understanding whether targeted training strategies can modify limb-specific performance and inter-limb asymmetry patterns may provide valuable insights into bilateral adaptations in young soccer players. Objective This study aimed to investigate the effects of an 8-week combined training program incorporating non-dominant-leg-focused technical exercises and unstable-surface training on limb-specific dynamic postural control, inter-limb asymmetry, and soccer-specific performance in young soccer players. Methods Thirty male U12 soccer players were randomly assigned to an experimental group (n = 15) or a control group (n = 15). Both groups trained twice weekly for 8 weeks with the same training frequency and session duration. The experimental group performed three technical exercises focused on the non-dominant leg and one dynamic bipodal unstable-surface exercise performed on unstable balance cushions, whereas the control group followed conventional soccer training. Results Compared with conventional soccer training, the combined training program was associated with greater improvements in dynamic postural control and selected non-dominant-leg soccer-specific performance outcomes. Limb-specific analyses indicated that training-related adaptations differed according to limb condition and task characteristics. Improvements were also observed in selected absolute and signed asymmetry measures; however, asymmetry responses were not uniform across outcomes. Conclusion The findings suggest that an 8-week combined training program integrating non-dominant-leg technical exercises with dynamic bipodal unstable-surface exercises may improve selected aspects of dynamic postural control and soccer-specific performance in male U12 soccer players. Limb-specific analyses and signed asymmetry assessment provided additional information regarding bilateral adaptations. However, because the intervention combined two training components, the independent contribution of each component cannot be determined, and these findings should be considered preliminary.