Evaluation of the immediate effect of two types of ankle-foot orthosis on Peroneus longus muscle onset latency in response to sudden ankle perturbation in athlete with functional ankle instability.

Abstract

Background

Ankle sprain is one of the most common sports injuries. So that 10% to 25% of whole sports injuries involve ankle sprain. On the other hand, 70% to 80% of individuals who experienced a sprain, suffers from another ankle sprain at least one more time which result in chronic ankle instability. So many studies investigated the role of using orthosis in reducing the incidence of sprain, constricting the range of motion and neuromuscular function.

Objective(s)

Our aim to perform this study was to evaluate the influence of orthosis on neuromuscular function of peroneus longus muscle in response to sudden perturbation in athletes involved with functional ankle instability.

Methodology

12 female athletes with functional ankle instability and 18 healthy female athletes (age=21.5 ±2.9 years, range: 17 to 27, BMI=23.26±3) participated in this study. Unexpected perturbation in frontal plane exerted by using Ankle Perturbation System (APS) and simultaneous recording of electrical activity of peroneous longus muscle was performed with surface electromyography. Participants were tested under 3 conditions: without support, using Elastic orthosis and Semi-rigid stirrup-type orthosis.

Findings

Using every orthosis in healthy athletes lead to enhancement of the time of peroneous longus muscle response delay. In injured group, the time of onset latency reduced by using each of orthoses but this reduction didn't catch the significance level.

Conclusions

Although in this study, the time of peroneous longus muscle delay did not show significant changes by using orthoses but it seems that using ankle orthoses in athlete with functional ankle instability lead to increase in proprioception by stimulation of cutaneous muscle during sudden invertory perturbation.