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Updated: Jul 6, 2026
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Skeletal Muscle Neurovascular Coupling, Oxidative Capacity, and Microvascular Function with 'One Stop Shop' Near-infrared Spectroscopy
Published on: February 20, 2018
Relationship between muscle oxygenation and electromyography activity during sustained isometric contraction
Eiji Yamada1, Takashi Kusaka, Nobuo Arima
1Department of Rehabilitation, Faculty of Medicine, Kagawa University Hospital, Miki-cho, Kita-gun, Kagawa, Japan.
Clinical Physiology and Functional Imaging
|March 22, 2008
Summary
Changes in muscle oxygenation, measured by near-infrared time-resolved spectroscopy (TRS), correlate with electromyography (EMG) spectrum changes during sustained contractions. These findings suggest oxygenation levels reflect muscle fatigue.
Area of Science:
- Exercise Physiology
- Biomedical Engineering
Background:
- Muscle fatigue is a complex physiological process affecting performance.
- Electromyography (EMG) and near-infrared spectroscopy (NIRS) are non-invasive tools to study muscle function.
- Understanding the relationship between EMG and muscle oxygenation is crucial for assessing fatigue.
Purpose of the Study:
- To investigate the relationship between electromyography (EMG) spectrum changes and muscle oxygenation dynamics.
- To determine if near-infrared time-resolved spectroscopy (TRS) can reflect EMG-assessed muscle fatigue.
Main Methods:
- Subjects performed sustained isometric knee extensions at 50% maximal voluntary contraction.
- Surface EMG and TRS were simultaneously recorded from the vastus lateralis muscle.
- Mean power frequency (MPF) from EMG power spectrum and changes in oxygenated/deoxygenated hemoglobin/myoglobin (Hb/Mb) from TRS were analyzed.
Main Results:
- Significant relationships were found between the decrease in the slope of MPF and maximal changes in oxygenated and deoxygenated Hb/Mb.
- The rate of MPF decrease correlated with alterations in muscle oxygenation levels.
Conclusions:
- Changes in oxygenated and deoxygenated hemoglobin/myoglobin (Hb/Mb) are indicative of muscle fatigue.
- Near-infrared time-resolved spectroscopy (TRS) can provide insights into EMG-assessed muscle fatigue during isometric exercise.
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