The comparison of lower and upper extremity muscles activation during sudden ankle supination in patients with and without chronic ankle instability

BACKGROUND: The purpose of this study was comparison of lower and upper extremity muscles activation during sudden ankle supination in patients with and without chronic ankle instability (CAI). METHODS: In this study, 50 professional athletes were selected based on three questionnaires: FADI, FADI-Sport Criterion and Ankle Instability Questionnaire. The research's subjects divided to health and injured groups that every health and injured groups was consist of 11 female and 14 male. Then participants were equipped with electrodes on the tibialis anterior (TA), peroneus longus (PL), gastrocnemius lateralis (GL), soleus, gluteus medius (Gmed) and maximus (Gmax) muscles. Then we requested participants to drop off a 20-cm-high on ankle supinator device. Two aware task and two unaware task data was recorded. RESULTS: The MANOVA results showed that there was not a significant interaction between group x task types: F-(17,F-164)=0.90, P=0.60, Wilks's Lambda=0.70 and eta(2)=0.08. Also, we did not observe a significant difference for main effect of task types: F-(51,F-498)=0.80, P=0.67, Wilks's Lambda=0.70 and eta(2)=0.07. But we saw a significant difference for main effect of groups: F-(17,F-164)=2.7 4, P=0.001, Wilks's Lambda=0.70 and eta(2)=0.22. Tukey test results showed that gastrocnemius electromyographic (EMG) feedback, gluteus medius EMG feedforward, soleus EMG feedback, peroneus longus EMG feedback, sum of lower kinetic chain EMG feedback were different between health and CAI groups. According to these results, we may state that muscles feedback and feedforward utilizing depended on ankle situation. In this study, we used to artificial ankle sprain situation and saw that in instable and unexpected situation applied local and global muscles in chronic ankle sprain subjects differently. CONCLUSIONS: Based on the results of this research, we can recommend the use of a supinator device in rehabilitation exercises for ankle instability.