Running perturbations reveal general strategies for step frequency selection

Area of Science:

• Biomechanics
• Human Locomotion
• Motor Control

Background:

• Human walking energy minimization involves fast and slow control processes.
• It remains unclear if these processes are specific to walking or general to locomotion.

Purpose of the Study:

• Investigate if energy minimization strategies in running mirror those in walking.
• Determine if fast and slow control processes are general to human locomotion.

Main Methods:

• Used free response experiments with auditory metronome constraints on step frequency.
• Employed forced response experiments with rapid treadmill speed changes.
• Analyzed response times for step frequency adjustments in running.

Main Results:

• Both fast (1.47 ± 0.05 s) and slow (34.33 ± 0.50 s) processes dominated step frequency adjustments.
• The dynamics of these processes in running matched previous findings in walking.
• Magnitude and relative importance of fast and slow processes were similar between walking and running.

Conclusions:

• The identified fast and slow control mechanisms are fundamental strategies for minimizing energetic cost in human locomotion.
• These findings suggest a unified control strategy for efficient movement across different gaits.