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Updated: Jan 17, 2026
Evaluating Postural Control and Lower-extremity Muscle Activation in Individuals with Chronic Ankle Instability
Published on: September 18, 2020
Running with chronic ankle instability: Task-dependent stride-to-stride ankle kinematic variability in sagittal and
Yuki A Sugimoto1, Scott E Ross2
1Department of Physical Therapy and Human Movement Sciences, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, United States.
Background:
Chronic ankle instability (CAI) is characterized by repeated episodes of ankle "giving way" and long-term sensorimotor deficits. Although previous studies have reported altered movement variability in individuals with CAI, it remains unclear how this variability differs across limbs, planes of motion, and tasks with varying mechanical demands. This study investigated the influence of task demands on stride-to-stride ankle kinematic variability in the sagittal and frontal planes in individuals with unilateral CAI compared to healthy controls.
Methods:
Fifty physically active participants with (n = 24) and without (n = 26) CAI completed treadmill walking and running at self-selected speeds. Ankle kinematics were recorded bilaterally, and sample entropy (SampEn) was calculated from the first 200 consecutive strides per limb for each task. A four-way mixed ANOVA was conducted to examine the effects of group (CAI, control), limb (injured, uninjured), plane (sagittal, frontal), and task (walking, running) on ankle kinematic variability.
Results:
A significant interaction was found between group, limb, plane, and task (F(1,48) = 21.644, P < .001). During running, individuals with CAI exhibited reduced SampEn in the sagittal and frontal planes across the injured and uninjured limbs compared to healthy controls, indicating more predictable and constrained motor control. No group differences were observed during walking, suggesting similar motor control under lower task demands.
Significance:
CAI-related motor control alterations are more evident during higher-demand tasks such as running. The bilateral reduction in variability may reflect centrally mediated neuromuscular adaptations. Future research should explore the role of limb dominance, muscle activation, and real-world task variability to better understand motor control disruptions in individuals with and without CAI.
