Interpretation of EMG spectral alterations and alteration indexes at sustained contraction

1992 ◽  
Vol 73 (4) ◽  
pp. 1211-1217 ◽  
Author(s):  
G. M. Hagg
Keyword(s):  
Power Spectrum ◽  
Action Potential ◽  
Median Frequency ◽  
Mean Power ◽  
Mean Power Frequency ◽  
Zero Crossing ◽  
Factors Affecting ◽  
Fatigue Development ◽  
Substantial Progress ◽  
Power Frequency

Alterations of the electromyographic power spectrum have been studied extensively to assess fatigue development in the neuromuscular system. Usually, a data reduction has been applied to create an index based on the mean power frequency or the median frequency. The physiological origin of the spectrum alterations has been (and to some extent still is) incompletely known. However, during the 1980s, substantial progress has been made in this field. The factors affecting the electromyographic power spectrum discussed in this review are action potential velocity decrease, firing statistics alterations, action potential modification, muscle temperature, additional recruitment at fatigue, and force level. Their impact on three commonly used fatigue indexes, mean power frequency, median frequency, and zero crossing rate, is also reviewed.

The Measurement of Sensitivity of Numerical Parameters in Quantification of Local Muscle Fatigue

1998 ◽  
Vol 42 (12) ◽  
pp. 936-939 ◽  
Author(s):  
Jung-Yong Kim ◽  
Myung-Chul Jung
Keyword(s):  
Muscle Fatigue ◽  
Voluntary Contraction ◽  
Erector Spinae ◽  
Superior Performance ◽  
Median Frequency ◽  
Mean Power ◽  
Mean Power Frequency ◽  
Zero Crossing ◽  
Power Frequency ◽  
Local Muscle Fatigue

In order to find the most sensitive Electromyographic (EMG) parameter in quantification of local muscle fatigue (LMF), the first coefficient of Autoregression Model (ARC), Zero Crossing Rate (ZCR), Mean Power Frequency (MPF), Median Frequency (MF) have been analyzed and compared with each other in this study. Ten healthy male subjects participated in the experiment, and EMG signals were collected from the erector spinae muscle continuously for twenty seconds while subjects were isometrically extending their trunk. Various exertion levels such as 15%, 30%, 45%, 60%, and 75% of Maximal Voluntary Contraction (MVC) were also applied to the subjects. As results, ARC was found to be the most sensitive parameter at the level of 15% to 60% of MVC in terms of both slope and R2 value of regression model. On the other hand, MPF and ARC showed the highest R2 value at 60% and 75% level of MVC although MPF scored the lowest slope value at those levels. Moreover, MPF showed a superior performance to MF at 30% to 75% level of MVC.

Features for muscle fatigue computed from electromyogram and mechanomyogram: A new one

2016 ◽  
Vol 230 (12) ◽  
pp. 1096-1105 ◽  
Author(s):  
Şükrü Okkesim ◽  
Kezban Coşkun
Keyword(s):  
Muscle Fatigue ◽  
Frequency Ratio ◽  
Biceps Brachii ◽  
Median Frequency ◽  
Mean Power ◽  
Mean Power Frequency ◽  
Power Frequency ◽  
Ratio Change ◽  
The Mean ◽  
New Feature

Muscle fatigue produces negative effects in the performance and it may lead to a muscle failure. This problem makes the quantitative grading of muscle fatigue a necessity in ergonomic and physiological research. Moreover, the quantitative grading of muscle fatigue is needed to increase work and sport productivity and prevent several accidents that result from muscle fatigue. Even though there are many studies for this aim, there is no quantitative criterion for the evaluation of muscle fatigue. The main reason is that muscle fatigue is a complex physiological situation that is dependent on several parameters. Our aim in this study is to present a new feature to evaluate muscle fatigue and prove the reliability of the new feature by making correlation analyses between this with other features. For this aim, electromyography and mechanomyography signals were simultaneously recorded from the biceps brachii and triceps brachii muscles during the isometric and isotonic contractions of 60 healthy volunteers (30 females, 30 males). The mean power frequency and median frequency, which are used in the literature, were compared to the frequency ratio change, the new measure; correlations between the frequency ratio change and the mean power frequency and median frequency were analysed. There was a high correlation between the features, and frequency ratio change can be used to quantitatively evaluate muscle fatigue.

EMG Power Spectrum Analysis to Assess Muscle Fatigue under Isometric Endurance Work

1983 ◽  
Vol 27 (5) ◽  
pp. 372-373
Author(s):  
S. Deivanayagam ◽  
T. W. Carmichael
Keyword(s):  
Power Spectrum ◽  
Muscle Fatigue ◽  
Mean Power ◽  
Mean Power Frequency ◽  
Straight Line ◽  
Power Frequency ◽  
Emg Power Spectrum ◽  
Spectrum Shift ◽  
Local Muscle Fatigue ◽  
Isometric Work

A research experimental study was conducted to make use of EMG power spectrum shift to assess the local muscle fatigue induced by isometric work. Sixteen male volunteer subjects participated in the study. The results indicate that the shift in mean power frequency (MPF) and the time constant of the straight line relationship between in (MPF) and elapsed time are reliable objective measures of local muscular fatigue.

Measurement and Analysis of Surface Electromyogram and Handgrip Force

2011 ◽  
Vol 225-226 ◽  
pp. 1318-1322
Author(s):  
Dong Mei Hao ◽  
Yan Zhang ◽  
Dong Ye Zhang ◽  
Zheng Wan ◽  
Yi Yang
Keyword(s):  
Voluntary Contraction ◽  
Median Frequency ◽  
Force Level ◽  
Mean Power ◽  
Mean Power Frequency ◽  
Surface Electromyogram ◽  
Static Contraction ◽  
Power Frequency ◽  
Relationship Of ◽  
The Relationship

To investigate the relationship of surface electromyogram (sEMG) and handgrip force, a measurement system was developed. Ten healthy subjects were required to perform a series of static contraction trials by maintaining the force level with maximal voluntary contraction (MVC), 75%MVC, 50%MVC and 25%MVC respectively. Then they sustained MVC as long as possible until fatigue. The handgrip force and sEMG on the forearm muscles were recorded. Root mean square (RMS), mean power frequency (MPF) and median frequency (MF) of the sEMG were calculated with LabVIEW. The results show that RMS increased with force level during voluntary contraction, while MPF and MF shift to lower frequency during fatigue condition. These findings suggested that the designed system can be used to study forearm function.

Dependence of the mean power frequency of the electromyogram on muscle force and fibre type

1991 ◽  
Vol 142 (4) ◽  
pp. 457-465 ◽  
Author(s):  
B. GERDLE ◽  
K. HENRIKSSON-LARSÉN ◽  
R. LORENTZON ◽  
M.-L. WRETLING
Keyword(s):  
Fibre Type ◽  
Muscle Force ◽  
Mean Power ◽  
Mean Power Frequency ◽  
Power Frequency ◽  
The Mean

Surface electromyogram power spectrum in human quadriceps muscle during incremental exercise

1993 ◽  
Vol 74 (6) ◽  
pp. 2704-2710 ◽  
Author(s):  
D. Gamet ◽  
J. Duchene ◽  
C. Garapon-Bar ◽  
F. Goubel
Keyword(s):  
Principal Component ◽  
Quadriceps Muscle ◽  
Bicycle Ergometer ◽  
Linear Increase ◽  
Total Power ◽  
Test Surface ◽  
Mean Power ◽  
Mean Power Frequency ◽  
Incremental Test ◽  
Power Frequency

Spectral electromyographic (EMG) changes in human quadriceps muscles were studied to reinvestigate discrepant results concerning mean power frequency (MPF) changes during dynamic exercise. An incremental test consisting of a quasi-linear increase in mechanical power on a bicycle ergometer (for 20–100% of maximal aerobic power) was performed by forty subjects. During this test, surface EMGs from the quadriceps muscles showed that EMG total power (PEMG) increased with a curvilinear pattern for every subject, whereas MPF kinetics varied from one subject to another. PEMG changes had the same shape, which would lead to disappointing results in terms of discrimination between subjects. The ability of normalized MPF kinetics to define significant clusters of subjects was tested using a principal component analysis. This analysis led to the projection of all experiments onto a plane and revealed a relevant grouping of MPF profiles. Differences in MPF kinetics between clusters are interpreted in terms of various possibilities of balance between physiological events leading to an increase or a decrease in MPF.

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