Deviations in whole body angular momentum are largely corrected before foot placement

Area of Science:

• Biomechanics
• Human locomotion
• Motor control

Background:

• Accurate foot placement is crucial for maintaining stability during walking.
• Previous models often focused on the center of mass, but the role of whole-body angular momentum is less understood.

Purpose of the Study:

• To investigate whether whole-body angular momentum influences mediolateral foot placement control beyond linear momentum.
• To compare predictive foot placement models with and without angular momentum considerations.

Main Methods:

• Ten healthy adults walked on a treadmill at different speeds (2 and 5 km/h).
• Mechanical perturbations (translation and rotation) were applied at heel strike to alter linear and angular momentum.
• Whole-body kinematics were captured using 3D motion analysis and processed using OpenSim to calculate momentum.

Main Results:

• Translation perturbations significantly altered linear momentum with minimal angular momentum changes.
• Rotation perturbations induced substantial angular momentum deviations but smaller linear momentum changes.
• Including whole-body angular momentum provided only minimal improvements in predicting foot placement after rotation perturbations.

Conclusions:

• Mediolateral foot placement control during walking is primarily dictated by linear momentum dynamics.
• Angular momentum plays a limited role in mediolateral foot placement adjustments following the tested perturbations.