Abstract
Background and Objectives: Muscle atrophy caused by chronic ankle instability (CAI) can incur muscle weakness, altered movement patterns, and increased risk of injury. Previous studies have investigated the effects of rehabilitative exercises and neuromuscular electrical stimulation (NMES) on characteristics in CAI individuals, but few studies have examined their effects on foot and ankle muscle morphology. This study aimed to determine the effects of rehabilitative exercises and NMES on muscle morphology and dynamic balance in individuals with CAI. Materials and Methods: Participants with CAI (n = 47) were randomly divided into control (CG), rehabilitative exercise (REG), NMES (NG), and rehabilitative exercise and NMES combined (RNG) groups. The six-week intervention program consisting of rehabilitative exercises and NMES was applied to groups excluding CG. Muscle morphology and dynamic balance were evaluated using a portable wireless diagnostic ultrasound device and dynamic balance tests. For statistical analysis, an effect size with 95% confidence interval was calculated to assess mean differences according to intervention. Results: After six weeks, significant increases in morphology and dynamic balance were observed for all muscles except flexor hallucis longus (p > 0.05) in the intervention groups except for CG. However, no significant changes were observed in the CG (p > 0.05). Conclusions: These findings suggest that intervention programs may help prevent muscle atrophy and improve balance in CAI individuals.