Background: Ankle sprain is a common sports injury. While the effects of static constraints in stabilizing the ankle joint are relatively well understood, those of dynamic constraints are less clear and require further investigation.Purpose: This study was undertaken to evaluate the dynamic stability of the ankle joint during the landing phase of running and stop-jump maneuvers in athletes with and without chronic ankle instability (CAI).Study Design: Controlled laboratory study.Methods: Fifteen athletes with CAI and 15 age-matched athletes without CAI performed running and stop-jump landing tasks. The dynamic ankle joint stiffness, tibialis anterior (TA)/peroneus longus (PL) and TA/gastrocnemius lateralis (GL) co-contraction indices, ankle joint angle, and root-mean-square (RMS) of the TA, PL, and GL electromyographic signals were measured during each task.Results: During running, the CAI group exhibited a greater ankle inversion angle than the control group in the pre-landing phase (P =.012-.042) and a lower dynamic ankle joint stiffness in the post-landing phase (CAI: 0.109 ± 0.039 N•m/deg; control: 0.150 ± 0.068 N•m/deg; P =.048). In the stop-jump landing task, athletes with CAI had a significantly lower TA/PL co-contraction index during the pre-landing phase (CAI: 49.1 ± 19; control: 64.8 ± 16; P =.009). In addition, the CAI group exhibited a greater ankle inversion (P =.049), a lower peak eversion (P =.04), and a smaller RMS of the PL electromyographic signal in the post-landing phase (CAI: 0.73 ± 0.32; control: 0.51 ± 0.22; P =.04).Conclusion: Athletes with CAI had a relatively inverted ankle, reduced muscle co-contraction, and a lower dynamic stiffness in the ankle joint during the landing phase of sports maneuvers and this may jeopardize the stability of the ankle.Clinical Relevance: Sports training or rehabilitation programs should differentiate between the pre-landing and post-landing phases of sports maneuvers, and should educate athletes to land with an appropriate ankle position and muscle recruitment.
All Science Journal Classification (ASJC) codes
- Orthopedics and Sports Medicine
- Physical Therapy, Sports Therapy and Rehabilitation