Visual Disruption Influences Neuromechanics during Landing Cutting in Individuals with Chronic Ankle Instability.

CONTEXT: Individuals with chronic ankle instability (CAI) appear to demonstrate altered movement patterns when their vision is disturbed during simple tasks such as single-leg standing and walking. However, it remains unclear whether visual disruption by stroboscopic glasses alters movement patterns during landing cutting movements, considered highly demanding sports maneuvers that mimic a typical athletic movement.

OBJECTIVE: This study aimed to identify altered lower extremity kinematics and muscle activation when participants' vision was disrupted by stroboscopic glasses during landing cutting tasks in CAI patients.

DESIGN: A case control design.

SETTING: A controlled laboratory setting.

PATIENTS OR OTHER PARTICIPANTS: Eighteen CAI patients and 18 matched healthy controls volunteered to participate in the study. All participants performed 5 trials of landing cutting with (SV) and without (NSV) stroboscopic glasses.

MAIN OUTCOME MEASURES: Frontal and sagittal lower extremity kinematics, and 6 lower extremity muscle activations during the stance phase of landing cutting tasks with (SV) and without stroboscopic glasses (NSV).

RESULTS: CAI patients demonstrated more inversion angle from 18% to 22% and from 60% to 100% of the stance phase and more peroneal longus activation from initial contact to 18% of the stance phase under the SV condition compared to the NSV condition. There were no differences in knee and hip joint angles between the visual conditions for both groups.

CONCLUSIONS: When wearing stroboscopic glasses, CAI patients showed altered movement patterns, including increased inversion angle and peroneus longus activation during the stance phase of landing cutting. The results suggest that CAI patients may lack the ability to reweight sensory information to adapt their movement to visual disruption.