• Full Name: SAMUEL LING
• Affiliation/Institution: CUHK
• Country: Hong Kong S.A.R.

• Full Name: CHERYL CHIA
• Affiliation/Institution: CUHK
• Country: Hong Kong S.A.R.

Chronic Ankle Instability is one of the most common sports-related injuries. The peroneal muscles play a key role in the rehabilitation of ankle sprains; some postulate that the ability to improve peroneal muscle/tendon function is the key difference between individuals who recover well and those who do relatively poorly. This study aims to compare peroneal muscle quality between individuals with chronic ankle instability (CAI) and healthy controls, and to examine their relationship with ankle stability.

Methods: Sixty-five participants (35 with unilateral CAI, 30 healthy controls) were assessed. Ultrasound was used to assess the peroneal muscle structure and was correlated with functional strength and balance tests.

Results: 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.

Conclusion: 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.