Balancing postural control and motor inhibition during gait initiation

Area of Science:

• Biomechanics
• Motor Control
• Human Movement Science

Background:

• Sudden environmental changes require rapid adjustments to planned movements like gait initiation.
• Maintaining body stability during gait initiation and suppression is crucial for preventing falls.
• Anticipatory postural adjustments (APAs) play a key role in preparing for and executing gait.

Purpose of the Study:

• To investigate the relationship between the ability to stop a planned gait initiation and the maintenance of body stability.
• To examine how biomechanical factors and task-level variables influence gait initiation suppression.
• To identify critical thresholds for stopping movement during gait initiation.

Main Methods:

• Utilized a modified Stop Signal Task (SST) specifically designed for gait initiation.
• Measured changes in anticipatory postural adjustments (APAs) during both gait initiation and attempted suppression.
• Analyzed the interaction between trial-level variables (e.g., reaction time) and biomechanical factors (e.g., center of mass displacement).

Main Results:

• Found significant interactions between trial-level timing variables and biomechanical factors affecting the success of stopping gait initiation.
• Identified a critical biomechanical threshold beyond which successful cessation of stepping was improbable.
• Demonstrated that successful stopping is contingent on the interplay between motor commands and postural control mechanisms.

Conclusions:

• Limb action control and body equilibrium are strongly interconnected, particularly during gait initiation and stopping.
• The findings provide a framework within motor control for understanding action-postural coupling.
• This research can inform the development of injury prevention and rehabilitation strategies for movement and posture disorders.