Control of vertical posture while elevating one foot to avoid a real or virtual obstacle.

Area of Science:

• Biomechanics
• Human Movement Science
• Virtual Reality Research

Background:

• Vertical posture control is crucial for daily activities like obstacle avoidance.
• Understanding postural responses in virtual reality (VR) is vital for developing effective rehabilitation strategies.

Purpose of the Study:

• To compare vertical posture control during obstacle avoidance in real-world versus virtual reality (VR) environments.
• To analyze the impact of different VR delivery methods (head-mounted display [HMD] and 3D projector) on postural responses.

Main Methods:

• Ten healthy participants performed one-legged obstacle avoidance tasks.
• Measurements included foot acceleration, center of pressure, and leg/trunk muscle electrical activity.
• Data were analyzed across early postural adjustments (EPAs), anticipatory postural adjustments (APAs), and compensatory postural adjustments (CPAs).

Main Results:

• Foot elevation acceleration was significantly lower in the HMD condition compared to real and 3D projector conditions.
• Reduced leg and trunk muscle activity was observed for virtual obstacles (HMD, 3D projector) versus real obstacles, particularly during APAs and CPAs.
• Muscle activation onsets in the supporting limb occurred during EPAs and APAs.

Conclusions:

• Postural control strategies are modulated in VR, with distinct differences observed between real and virtual obstacle interactions.
• Altered muscle activity and movement patterns in VR necessitate consideration for virtual rehabilitation protocol design.