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Updated: Jul 7, 2026
14:02
Ex Vivo Assessment of Contractility, Fatigability and Alternans in Isolated Skeletal Muscles
Published on: November 1, 2012
Fatigue in high- versus low-force voluntary and evoked contractions
1Department of Kinesiology and Health Education, University of Texas, 1 University Station, D3700, Bellmont 222, Austin, TX 78712, USA. l.griffin@mail.utexas.edu
Experimental Brain Research
|February 20, 2008
Summary
Low-frequency fatigue (LFF) is more pronounced after low-force voluntary contractions compared to high-force or evoked contractions. The duration of the fatigue task significantly influences the degree of LFF.
Area of Science:
- Exercise Physiology
- Neuromuscular Physiology
Background:
- Low-frequency fatigue (LFF) is characterized by a greater force loss at low stimulation frequencies versus high frequencies.
- Understanding fatigue protocols is crucial for optimizing training and rehabilitation.
Purpose of the Study:
- To identify fatigue protocols most likely to induce LFF.
- To compare LFF induced by different contraction types and frequencies.
Main Methods:
- Ten participants underwent four fatigue protocols: intermittent high-frequency stimulation, intermittent low-frequency stimulation, sustained maximal voluntary contraction (MVC), and low-force voluntary contractions.
- Force-frequency relationships were assessed using short stimulation trains (10-80 Hz) before and after fatigue tasks.
Main Results:
- LFF was significantly higher following low-force voluntary contractions (20% MVC) compared to high-force voluntary contractions (100% MVC) and evoked contractions.
- The duration of the fatigue task and the reduction in maximal force output were key factors correlating with LFF severity during low-force voluntary contractions.
Conclusions:
- Low-force voluntary contractions are more effective at inducing LFF than high-force or evoked contractions.
- Fatigue task duration is a primary determinant of LFF severity, particularly during submaximal voluntary efforts.
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