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Identifying head-trunk and lower limb contributions to gaze stabilization during locomotion
Ajitkumar P Mulavara1, Jacob J Bloomberg
1National Space Biomedical Research Institute, Bobby R. Alford Department of Otorhinolaryngology and Communicative Sciences, Baylor College of Medicine, Houston, TX 77030, USA. amulavar@ems.jsc.nasa.gov
Journal of Vestibular Research : Equilibrium & Orientation
|September 23, 2003
Summary
The body adjusts gait to stabilize gaze during locomotion when visual tasks become more demanding. This involves increased head movement and knee flexion, reducing head acceleration.
Area of Science:
- Biomechanics
- Human sensorimotor control
- Gait analysis
Background:
- Gaze stabilization is crucial for locomotion.
- Sensorimotor systems adapt to changing task demands.
Purpose of the Study:
- To investigate how sensorimotor subsystems adapt to altered gaze stabilization during walking.
- To test if increased visual acuity demands modify full-body kinematics for head stability.
Main Methods:
- Nine subjects walked at 6.4 km/hr on a treadmill performing two tasks: focusing on a target and reading numbers.
- Measured gait parameters, full-body kinematics, head/tibia acceleration, and vertical forces.
- Analyzed head and trunk coordination and joint movements.
Main Results:
- Reading numbers increased compensatory head pitch (22%) without altering trunk control.
- Knee joint movement increased (11%) during stance phase.
- Peak head acceleration decreased (13%) in most subjects, despite unchanged tibia acceleration and shock transmission.
- Head-trunk coordination patterns remained consistent.
Conclusions:
- The full body actively contributes to gaze stabilization during locomotion.
- Sensorimotor systems dynamically adjust kinematic strategies based on visual task requirements.
- Modifications in gait kinematics help maintain head stability under varying visual conditions.