Extraction of basic movement from whole-body movement, based on gait variability

Area of Science:

• Biomechanics
• Human Movement Science
• Neuromuscular Control

Background:

• Understanding running gait variability is crucial for deciphering neuromuscular control strategies.
• Previous research has not fully distinguished between speed-dependent and speed-independent gait components.

Purpose of the Study:

• To quantify step-to-step variability (SSV) in speed-variant and speed-invariant components of whole-body running gait.
• To investigate how SSV changes across different running speeds.
• To gain insights into neuromuscular control during running.

Main Methods:

• Ten male recreational athletes performed treadmill running trials at five speeds (1.3-4.9 m/s).
• Principal Component Analysis (PCA) separated whole-body movement into principal movements (PMs).
• PMs were classified as speed-variant or speed-invariant based on range of motion changes with speed. SSV was calculated as absolute and relative measures.

Main Results:

• Absolute SSV of speed-variant movements increased with running speed.
• Relative SSV of speed-variant movements decreased asymptotically with increasing speed.
• Both absolute and relative SSV of speed-invariant movements showed a minimum at 3.1 m/s.

Conclusions:

• The whole-body gait pattern during running can be divided into speed-variant and speed-invariant components.
• Speed-variant movements appear more tightly controlled, exhibiting lower variability relative to their amplitude.
• Speed-invariant movements demonstrate a specific optimal speed for minimal variability, suggesting distinct control mechanisms.