Comparison of the Effect of 6 Weeks of Balancing and Hopping Strengthening Training on the Kinematics of the Lower Extremities of Athletes with Functional Ankle Instability while Running: A Randomized Controlled Trial

Introduction: Ankle sprains are one of the most common sports injuries. This injury can affect the kinematics of the athletechr('39')s lower extremities. Therefore, the aim of this study was to compare the effect of 6 weeks of balancing and hopping strengthening training on the kinematics of the lower extremities of athletes with functional ankle instability while running. Methods: The present study  was a randomized clinical trial on 36 athletes with functional ankle instability who were randomly divided into three groups: hopping training, balance strengthening and control. The training lasted for six weeks and 3 sessions per week. Kinematic data were recorded by 3D OptiTrack camera while running at 10 km/h before and after training. SPSS software version 20 and ANCOVA test were used to compare the effect of exercises. Results: The results showed that there was a significant difference among the 3 groups in dorsiflexion (P = 0.009), inversion (P = 0.001) and knee flexion (P = 0.001). The results of Benferoni test also showed that hopping training in dorsiflexion, ankle inversion and knee flexion were significantly different from the control group (P = 0.009, P = 0.001, P = 0.001). The results also showed that balance strengthening training in the above movements were significantly different from the control group (P = 0.005, P = 0.002, P = 0.006) and in knee flexion, hoping training showed a significant difference compared to balance strengthening training (P =0.012). The results showed that both hopping and balance strengthening training improved the dorsiflexion, inversion and knee flexion angles in the initial contact in running. However, hopping exercises is better than balance strengthening in improving knee flexion angles. Conclusion: Therefore, according to the presented results, it can be concluded that the rehabilitation course of ankle sprains in athletes, coaches and sports rescue specialists should use a combination of balance strengthening training and hopping as a comprehensive program. In addition, hopping training can be used as a good alternative to balance training in places where there is not enough equipment.