The effect of rapid expansion and contraction composite training on dynamic posture control and landing biomechanics of athletes with chronic ankle instability
Qian Wan · South Florida Journal of Health · 2026
Objective: To explore the effects of rapid extension and contraction composite training on dynamic posture control and landing biomechanical characteristics of athletes with chronic ankle instability.
Methods: A randomized controlled trial
Design: was used to randomly divide 56 athletes with chronic ankle instability who met the inclusion criteria into an experimental group (n=28) and a control group (n=28). The experimental group underwent a rapid expansion and contraction composite training for 8 weeks, 3 times a week, while the control group received routine rehabilitation training. Evaluate the comprehensive score of Y balance test, landing biomechanical parameters (ankle plantarflexion angle, peak vertical ground reaction force, loading rate), and Cumberland Ankle Instability Scale (CAIT) score before and after intervention.
Results: Among the 56 participants, 51 (25 in the experimental group and 26 in the control group) completed all interventions, and there was no significant difference in completion rate between the two groups (P>0.05). At baseline, there were no significant differences (P>0.05) in the comprehensive scores of the Y balance test between the two groups, as well as in the contact distance in all directions, landing biomechanical parameters, and CAIT scores. After intervention, the comprehensive score improvement of Y balance test in the experimental group was significantly better than that in the control group (P<0.001, d=0.92). In all directions of testing, the experimental group showed a significant increase in the forward, posterior medial, and posterior lateral contact distances, with the posterior medial direction showing the most significant improvement (P<0.001). In terms of landing biomechanics, the experimental group showed a significant reduction in ankle plantarflexion angle (P<0.001), peak vertical ground reaction force, and loading rate (P<0.05), and the improvement in all three indicators was greater than that in the control group. The CAIT score of the experimental group also significantly improved (P<0.001). No serious adverse events occurred in either group. Sensitivity analysis showed that the
results of the protocol analysis were consistent with those of the intention to treat analysis, indicating the robustness of the research
Conclusions: .
Conclusion: Rapid extension and contraction composite training can effectively improve the dynamic posture control ability of athletes with chronic ankle instability, optimize the landing biomechanical mode, and reduce the risk of ankle joint re injury.