Anticipatory postural control emerges from a predictive and optimized strategy for movement preparation

Area of Science:

• Biomechanics
• Neuroscience
• Robotics

Background:

• Humans exhibit anticipatory postural adjustments before predictable external perturbations.
• The coordination of forward center of mass (COM) motion with backward-acting muscle activation (gastrocnemius muscle, GC) during these responses is not fully understood.

Purpose of the Study:

• To investigate if anticipatory postural responses to predictable backward floor tilts can be explained by predictive optimal control.
• To explore the underlying control mechanisms coordinating COM movement and muscle activation.

Main Methods:

• Experiments involving auditory cues to elicit predictable backward floor tilts.
• Development of a musculoskeletal simulation model governed by model predictive control (MPC).

Main Results:

• Experiments confirmed anticipatory COM shifts and GC activation during forward movement.
• The MPC simulation successfully reproduced the observed human anticipatory behaviors.
• Simulation indicated forward COM shift leverages gravity while GC activation provides ankle stabilization.

Conclusions:

• Anticipatory postural responses can be explained by optimizing predicted future states using internal models.
• The findings highlight the role of gravitational dynamics in efficient motor preparation and predictive control.
• This study provides insights into the neural control of balance and movement.