After-Fatigue Condition: A Novel Analysis Based on Surface EMG Signals

TL;DR

This paper presents a new surface EMG-based method to analyze muscle after-fatigue conditions, revealing significant activation changes that can aid clinical and sports applications.

Contribution

It introduces a comprehensive analysis of after-fatigue muscle states using amplitude, spectral, and conduction velocity parameters, filling a gap in fatigue research.

Findings

Higher conduction velocity in after-fatigue condition

Spectral density shifts to higher frequencies post-fatigue

Longer contraction times until exhaustion after fatigue

Abstract

This study introduces a novel muscle activation analysis based on surface electromyography (sEMG) signals to assess the muscle's after-fatigue condition. Previous studies have mainly focused on the before-fatigue and fatigue conditions. However, a comprehensive analysis of the after-fatigue condition has been overlooked. The proposed method analyzes muscle fatigue indicators at various maximal voluntary contraction (MVC) levels to compare the before-fatigue, fatigue, and after-fatigue conditions using amplitude-based, spectral-based, and muscle fiber conduction velocity (CV) parameters. In addition, the contraction time of each MVC level is also analyzed with the same indicators. The results show that in the after-fatigue condition, the muscle activation changes significantly in the ways such as higher CV, power spectral density shifting to the right, and longer contraction time until exhaustion compared to the before-fatigue and fatigue conditions. The results can provide a comprehensive and objective evaluation of muscle fatigue and recovery, which can be helpful in clinical diagnosis, rehabilitation, and sports performance.