Unilateral Ankle Force Control With and Without Chronic Ankle Instability

PURPOSE: Repetitive lateral ankle sprains often cause chronic ankle instability (CAI) leading to various sensorimotor deficits. This study aimed to investigate altered ankle dorsiflexion force control capabilities in individuals with CAI.METHODS: Ten young adults with unilateral CAI performed isometric ankle dorsiflexion force control at 20% of the maximum voluntary contraction under vision and no-vision conditions. Participants executed submaximal force control tasks with their impaired and non-impaired ankles. To evaluate the force control capabilities, we estimated the force trend, accuracy, and variability. Two-way repeated-measures ANOVAs (ankle×vision, 2×2) for each force control variable were used for statistical analyses.RESULTS: When the visual information was removed, a declining force trend was observed in the impaired ankle (p<.001), whereas no differences were observed in the non-impaired ankle (p=.096). In the no-vision condition, the impaired ankle showed a lower mean force (p=.035) and force accuracy (p=.009) and greater force variability (p=.004) than the non-impaired ankle.CONCLUSIONS: These findings suggest that CAI interferes with ankle dorsiflexion force control without visual information, indicating sensorimotor impairment.