Evaluation of peroneal muscle thickness and muscle strength in individuals with unilateral chronic ankle instability

Aims: The aim of this study was to compare peroneal muscle thickness and ankle circumference muscle strength between the affected and unaffected sides in individuals with unilateral chronic ankle instability. Methods: Thirty-four participants with unilateral chronic ankle instability were included in the study. The foot posture of participants with unilateral chronic ankle instability was evaluated with the Foot Posture Index, the strength of the muscles around the ankle was evaluated with a hand-held dynamometer, and peroneus longus (PL) and peroneus brevis (PB) muscle thicknesses were evaluated with ultrasonography. Since the normal distribution assumption was not met, measurements of the affected and unaffected extremities were compared using the Wilcoxon signed rank test. Results: As a result of the study, both PB (p=0.024) and PL (p=0.043) muscle thicknesses of the participants were thinner on the affected side. When the muscle strength of the participants on the affected and unaffected sides was examined, no statistically significant difference was observed between the two sides for plantar flexor, dorsiflexor, invertor, and evertor muscle strength (p>0.05). Conclusion: As a result, in participants with unilateral chronic ankle instability, PL and PB muscle thickness were less on the affected side. Furthermore, there was no difference in muscle strength between the sides in participants with unilateral chronic ankle instability.