Corticomotor Excitability Changes Induced by Progressive Balance Exercises in Chronic Ankle Instability: a Randomized Clinical Trial

ABSTRACT Background Progressive balance exercises may change corticomotor excitability during the learning process of postural stability control. The primary purpose of the present study was to assess corticomotor excitability corresponding to the peroneus longus muscle under transcranial magnetic stimulation following 6 weeks of progressive balance exercises in individuals with chronic ankle instability. Methods Eligible volunteers diagnosed with chronic ankle instability were randomly assigned to either the intervention group or the control group. The intervention group practiced progressive balance exercises every other day for 6 weeks, while the control group continued their daily activities. The corticomotor excitability outcome measures included the active and resting corticomotor thresholds, the motor evoked potential, and the cortical silent period of the peroneus longus muscle, which were measured using an electromyography device under a transcranial magnetic stimulator. The outcome measures were measured in the intervention group before and after progressive balance exercises, and in the control group at baseline and again after a 6‐week interval. Results The corticomotor thresholds and cortical silent period of the peroneus longus muscle were significantly decreased within groups ( p ‐values < 0.001; η 2 p > 0.580). In addition, the normalized motor evoked potential of the peroneus longus muscle exhibited a significant increase within groups ( p ‐value < 0.001; η 2 p = 0.265). Interestingly, a significant interaction effect was revealed between the within‐group and between‐group effects for the corticomotor excitability outcome measures related to the peroneus longus muscle ( p ‐values < 0.001; η 2 p > 0.311). Conclusions Six weeks of progressive balance exercises significantly increased corticomotor excitability corresponding to the peroneus longus muscle in individuals with chronic ankle instability.