Using a System-Based Monitoring Paradigm to Assess Fatigue during Submaximal Static Exercise of the Elbow Extensor...

Area of Science:

• Biomechanics
• Human Physiology
• Motor Control

Background:

• Current fatigue evaluation methods analyze muscles and movement output independently.
• A system-based approach offers a more integrated perspective on fatigue.

Purpose of the Study:

• To investigate a system-based monitoring paradigm for assessing muscle fatigue.
• To determine if a dynamic relationship metric between muscle activity and force is a viable fatigue indicator.
• To discuss improvements for online fatigue assessment.

Main Methods:

• Eight participants performed static elbow extension to exhaustion.
• Surface electromyography (sEMG) and force data were collected.
• A dynamic time-series model linked sEMG features of synergistic muscles to force output.
• The Freshness Similarity Index (FSI) was derived from modeling errors.

Main Results:

• The FSI demonstrated significant within-individual correlations with maximum voluntary contraction (MVC) force (r=-0.86) and ratings of perceived exertion (RPE) (r=0.87).
• Time-dependent changes in the dynamic model indicated performance degradation.
• The FSI proved to be a viable metric for assessing fatigue.

Conclusions:

• A system-based monitoring paradigm provides a viable method for fatigue assessment.
• The FSI offers a direct, quantitative link between system performance degradation and traditional fatigue measures.
• This study validates a novel approach to understanding and quantifying muscle fatigue.