Self-paced treadmill speed differentially affects gait variability and stability in walking and running

Area of Science:

• Biomechanics
• Human locomotion
• Gait analysis

Background:

• Self-paced treadmills offer adaptable locomotion compared to fixed-speed models.
• Understanding their impact on gait variability and stability, especially during running, is crucial.

Purpose of the Study:

• To compare self-paced (SFP) and constant-speed (CON) treadmill locomotion in healthy adults.
• To investigate effects on spatiotemporal gait characteristics, global stability, and local dynamic stability during walking and running.

Main Methods:

• Twenty-eight adults performed SFP and CON walking and running trials at matched average speeds.
• Spatiotemporal variables (stride length, step frequency, etc.) and their variability (CV) were assessed.
• Global stability (DFA) and local dynamic stability (Lyapunov exponent) were evaluated.

Main Results:

• Walking: SFP increased stride length and variability, decreased stance ratio, and reduced local dynamic stability.
• Running: No significant differences in spatiotemporal variables, variability, or global stability between SFP and CON.
• Running: SFP improved local dynamic stability in the trunk, shank, and foot.

Conclusions:

• Gait responses to self-paced treadmill speed regulation are mode-specific.
• Walking is more affected by speed constraints, showing increased variability and reduced stability.
• Running gait characteristics and dynamics are preserved on self-paced treadmills.