Lower extremity joint-level responses to pelvis perturbation during human walking

Area of Science:

• Biomechanics
• Human locomotion
• Neuroscience

Background:

• Human leg joints are crucial for maintaining balance during walking.
• They control leg swing and ground reaction forces to prevent falls.
• Understanding joint-level control during perturbed walking is key to balance recovery.

Purpose of the Study:

• To investigate joint-level control mechanisms during perturbed human walking.
• To analyze balance recovery strategies in response to anteroposterior and mediolateral pelvis perturbations.
• To explore the contributions of different leg joints and muscle activity to balance control.

Main Methods:

• Healthy subjects received random pelvis perturbations during walking.
• OpenSim software was used for inverse kinematics and dynamics analysis.
• Electromyography (EMG) recorded muscle activity.

Main Results:

• Hip joint actively controls leg swing for foot placement.
• Stance leg ankle and hip joints modulate velocity to counteract perturbations.
• Balance control involves multi-joint coordination in both frontal and sagittal planes.
• Muscle activity indicates both spinal and supra-spinal contributions to balance recovery, scaling with perturbation intensity.

Conclusions:

• Human walking balance recovery is a complex, multi-joint process.
• Active joint control and muscle responses are essential for maintaining stability.
• The study provides detailed insights into the neural control of balance during walking.