Association Between Single-Leg Drop Landing Postural Control and Isokinetic Ankle Muscle Strength in Females with Chronic Ankle Instability.

Abstract

This study investigates the relationship between isokinetic ankle strength and dynamic postural control during single-leg drop landing (SLDL) in females with chronic ankle instability (CAI). Ankle muscle strength is vital for stability, yet the relationship between isokinetic strength and SLDL postural control remains underexplored in this population. To investigate associations between isokinetic ankle strength (dorsiflexion, plantar flexion, inversion, eversion) and dynamic postural stability during forward, medial, and lateral SLDL in females with CAI. correlational strategy study. Forty-two physically active females with CAI (mean age 29.4 ± 6.5 years, CAIT score 17.7 ± 5.0) underwent isokinetic dynamometry at 60°/s and 120°/s to measure peak torque normalized to body mass. Dynamic postural control was assessed via center of pressure (COP) deviations during SLDL from a 16-cm platform. Spearman's correlations analyzed relationships (p < 0.05). Forward SLDL COP deviations negatively correlated with invertor (rs = -0.538 to -0.522), evertor (rs = -0.575 to -0.484), plantar flexor (rs = -0.619 to -0.658), and dorsiflexor (rs = -0.423) peak torques (all p ≤ 0.005). Medial SLDL COP deviations negatively correlated with evertor-to-invertor ratios (rs = -0.335 to -0.384, p ≤ 0.030). No significant correlations emerged for lateral SLDL. Isokinetic ankle strength is associated with reduced COP deviations in forward SLDL, while evertor-to-invertor ratios support medial SLDL stability. These findings highlight direction-specific demands, informing targeted rehabilitation for CAI. Level 4.