Investigating peroneus muscle quality in ankle stability: A comparative analysis between chronic ankle instability...

To compare peroneal muscle quality between individuals with chronic ankle instability (CAI) and healthy controls, and to examine their relationship with ankle stability.

Case-control study.

Sports Medicine research laboratory.

Sixty-five participants (35 with unilateral CAI, 30 healthy controls) were assessed. Peroneal muscle size, echogenicity, and passive stiffness were measured using ultrasound imaging and eversion strength was assessed with a hand-held dynamometer. Ankle stability was evaluated using the Y Balance Test (YBT), lateral step-down, and single-leg stance tests.

Compared to controls, individuals with CAI showed significantly lower eversion strength, higher muscle echogenicity, and increased passive stiffness. In the CAI group, greater stiffness and reduced strength were associated with higher centre of pressure displacement during single-leg stance. Higher eversion strength was associated with increased YBT scores across all participants. Echogenicity was not directly associated with stability functions.

Deficits in peroneal muscle quality, involving echogenicity, strength and stiffness, are demonstrated in the CAI population. These factors are associated with impaired instability among CAI individuals. Interventions targeting peroneal muscle quality may improve balance and reduce the risk of recurrent ankle injuries in this population.