Establishing a methodological framework for evaluating gait symmetry through muscle synergies: A pilot study

Area of Science:

• Biomechanics
• Neuroscience
• Human Movement Science

Background:

• Gait symmetry is crucial for stable locomotion.
• Conventional gait symmetry metrics can be inconsistent.
• Muscle synergy analysis offers a precise method to understand neural control of gait.

Purpose of the Study:

• To refine muscle synergy symmetry analysis in healthy individuals.
• To establish intra-limb similarity as a baseline for inter-limb comparison.
• To investigate muscle weightings within synergies for synchrony analysis.

Main Methods:

• Collected electromyography (EMG) signals from lower limbs during treadmill walking.
• Extracted muscle synergies using non-negative matrix factorization (NMF).
• Compared muscle synergies, weightings, and activation coefficients between limbs using normalized scalar products and Pearson's correlation.

Main Results:

• No significant differences in the number or structure of muscle synergies between limbs.
• Significant differences observed in the activation of four out of eight muscles.
• Minor variations noted in muscle weightings between the left and right limbs.

Conclusions:

• Muscle synergy analysis indicates symmetrical coordination patterns in healthy gait.
• Refined methodologies are essential to differentiate true inter-limb differences from natural variability.
• This study emphasizes the need for robust frameworks in interpreting muscle synergy symmetry.