Altered visual focus on sensorimotor control in people with chronic ankle instability

Area of Science:

• Biomechanics
• Motor Control
• Sports Medicine

Background:

• Chronic ankle instability (CAI) is a prevalent condition affecting dynamic stability.
• Visual input significantly influences sensorimotor control and postural strategies.
• Understanding how CAI and visual focus interact is crucial for injury prevention and rehabilitation.

Purpose of the Study:

• To investigate the combined effects of chronic ankle instability (CAI) and altered visual focus on dynamic stability during a drop-jump task.
• To compare movement strategies between individuals with CAI and healthy controls under different visual conditions.
• To determine if visual focus influences the sensorimotor control adaptations in individuals with CAI.

Main Methods:

• Nineteen participants with CAI and 19 healthy controls performed a drop-jump task.
• Participants completed the task under two visual conditions: looking up (reading a number) and looking down (focusing on the force plate).
• Sagittal- and frontal-plane kinematics (hip, knee, ankle) and ground reaction forces were analyzed at pre-contact and initial contact phases.

Main Results:

• The CAI group exhibited significantly less hip flexion pre-contact and at initial contact compared to controls.
• Reduced knee flexion at initial contact was also observed in the CAI group.
• No significant differences in kinematics or dynamic stability were found between the looking-up and looking-down conditions for either group.

Conclusions:

• Altered visual focus did not impact movement patterns or dynamic stability during the drop-jump task.
• The presence of chronic ankle instability, however, led to significant alterations in movement strategies, particularly at the hip and knee.
• These findings suggest that CAI may involve centrally mediated changes affecting global sensorimotor control, independent of visual input manipulation.