Purpose:
Non-contact lower limb injuries, particularly anterior cruciate ligament (ACL) tears, are highly prevalent among adolescent football players. Considering the importance of early interventions in enhancing neuromuscular performance, this study aimed to examine the effects of corrective exercises with and without the STOP-X program on dynamic knee valgus, proprioception, and dynamic balance in adolescent football players.
Methods:
In this quasi-experimental pre-test–post-test study with a control group, 30 male adolescent football players (aged 12–16 years) with dynamic knee valgus were purposively selected from youth football academies in Isfahan, Iran, and randomly assigned to three groups: (1) corrective exercises + STOP-X, (2) corrective exercises only, and (3) control. Interventions were conducted over eight weeks: the STOP-X program was performed twice per week during the first four weeks and three times per week during the last four weeks (20–30 minutes per session), whereas the corrective exercise program was implemented three times per week throughout the eight weeks (45–60 minutes per session). Knee dynamic valgus was assessed using the single-leg drop landing test, knee joint proprioception was evaluated with the active joint position reproduction test, and dynamic balance was measured using the Y-balance test, all conducted before and after the interventions. Data were analyzed using repeated-measures ANOVA at a significance level of 0.05.
Results:
Significant main effects of time and group × time interactions were observed for all variables (p<0.01). The combined training group (corrective + STOP-X) showed significant and large effects in reducing dynamic knee valgus angle, improving proprioception, and enhancing dynamic balance compared with the other groups. The corrective-only group also improved significantly relative to the control group, though to a lesser extent than the combined intervention.
Conclusion:
The combination of corrective exercises with the Stop-X program resulted in a significant reduction in dynamic knee valgus, improved joint proprioceptive accuracy, and enhanced dynamic balance in adolescent football players. The large effect sizes indicate the clinical efficacy of this multifaceted intervention and suggest that structured implementation of such programs may serve as an effective approach for reducing non-contact injury risk and improving movement safety during the developmental years.