Middle Eastern Journal of Disability Studies

Abstract
Background & Objectives: Ankle injury is one of the most common sports and daily life injuries. Usually, in 15%–60% of cases, Functional Ankle Instability (FAI) occurs after the initial sprain of the ankle. People with FAI have different muscle recruitment patterns and neuromuscular firing rates than healthy people. The human body relies on three sensory systems to maintain balance: vision, somatosensory, and vestibular. Information obtained from weight can be united by all three systems in the central nervous system, and balance can be established. Virtual reality technology is a new way to create more visual impairment and instability. By providing unreal visual cues, virtual reality makes the central nervous system rely on somatosensory and vestibular to maintain balance. This study aims to investigate the electromyographic activity of selected lower limb muscles in feedback and feedforward phases with and without using virtual reality in male badminton players with and without FAI.
Methods: The current research method was quasi–experimental. The statistical population of this research comprised Badminton athletes aged 15 to 18 who were playing at the professional level. Thirty Badminton players were divided into two groups with and without ankle instability, and each group included 15 subjects. The Cumberland Ankle Instability Tool (Hiller et al., 2006) was used to diagnose FAI. The group with FAI received a Cumberland questionnaire score of 0 to 27, and the control group received a score of 27 to 30. The Anterior Drawer of the Ankle Test was performed to ensure the absence of mechanical instability, and if the participants showed mechanical instability, they were excluded from the research. Motion Lab System MA400 (DTU) device was used to measure the electrical activity of muscles, and the F–RG model electrode was made by Skintact. The electromyographic activity of the tibialis anterior, peroneus longus, and lateral gastrocnemius muscles in the feedforward and feedback phases was studied using virtual reality. After checking the normality of the data, the independent t test and Man–Whitney U test were used to analyze the data at a significance level of 0.05 using SPSS 27.
Results: The independent t test and Man–Whitney U test results showed a significant difference in the feedforward and feedback phases between the groups with FAI and without FAI regarding the tibialis anterior, peroneus longus muscles activities (p<0.05). When using Virtual Reality in the feedforward phase, there is a significant difference between the tibialis anterior (p=0.003) and lateral gastrocnemius muscles (p<0.001) in the group with and without FAI when using virtual reality. It should be noted that the activity of the tibialis anterior and lateral gastrocnemius muscle in the group without functional instability of the ankle in the feedforward phase was higher than the group with FAI. Also, a significant difference was observed in the feedback phase in the tibialis anterior (p=0.006) and the lateral gastrocnemius muscle (p<0.001) between the group with and without ankle functional instability. It should be noted that the activity of the tibialis anterior and lateral gastrocnemius muscle in the group without ankle functional instability in the feedback phase was higher than in the group with ankle functional instability. Also, there is no significant difference between the FAI and non–FAI groups regarding peroneus longus.
 Conclusion: According to the results, virtual reality can change the electromyography activity of the ankle muscles. There are changes in the electromyographic activity of the tibialis anterior and lateral gastrocnemius muscle when using virtual reality between athletes with and without FAI, indicating the effect of virtual reality on the electromyographic activity of ankle muscles in these people.