Effects of two different electrical stimulation mode on muscle reaction time and proprioception in functional ankle instability

The aim of this study was to investigate the effects of different electrical stimulation modes on muscle reaction time and ankle proprioception in patients with functional ankle instability. 36 recreational athletes with functional ankle instability were randomly allocated to standard electrical stimulation (SE) (n = 13), personalized electrical stimulation (PE) (n = 13) and control (n = 10) groups. Electrical stimulation was applied to the peroneus longus (PL) and tibialis anterior (TA) muscles of the participants in the electrical stimulation groups for 20 minutes a day, 3 days a week during 6 weeks. At the beginning of the study, muscle reaction time measurements were made on the inversion simulation platform with the EMG device, in neutral and plantar flexion positions, with the ankle going to 15 ° and 30 ° inversion, respectively. In addition, star excursion balance test for dynamic balance evaluation, kinesthesia, passive and active joint position sense, and isometric strength measurements were applied. Measurements were repeated after 6 weeks of electrostimulation. A statistically significant shortening was observed in peroneus longus muscle reaction times for the SE group at neutral 30 ° (p<0.05) and at plantar flexion 15 ° and 30 ° (p<0.01), also in the PE group at plantar flexion 15 ° position (p<0.01) compared to the control group. A statistically significant shortening in tibialis anterior muscle reaction time was found in the SE group at plantar flexion 30 ° position (p<0.05) if compared with control group. The star excursion balance test, in which dynamic balance was evaluated, revealed statistically significant improvements in both electrical stimulation groups compared with control group (p<0.05-0.001). Neither in muscle reaction time nor in star excursion balance test values were statistically different between electrical stimulation groups. Furthermore, no statistically significant difference were observed between groups in kinesthesia, joint position sense, and isometric strength measurement results. In the light of these findings, it can be concluded that, with a six week electrical stimulation of the peronues longus and tibialis anterior muscles improves muscle reaction time and dynamic balance in individuals with functional ankle instability. It may be beneficial to adding electrical stimulation in rehabilitation programs for patients with functional ankle instability and in preventing ankle injuries for healthy people.