Motor Unit Firing Rate During Static Contraction Indicated by the Surface EMG Power Spectrum

1983 ◽  
Vol BME-30 (9) ◽  
pp. 601-609 ◽  
Author(s):  
Anton Van Boxtel ◽  
Lambert R. B. Schomaker
Keyword(s):  
Power Spectrum ◽  
Firing Rate ◽  
Motor Unit ◽  
Surface Emg ◽  
Motor Unit Firing ◽  
Static Contraction ◽  
Emg Power Spectrum

Surface EMG crosstalk quantified at the motor unit population level for muscles of the hand, thigh, and calf

2021 ◽  
Author(s):  
Carina Marconi Germer ◽  
Dario Farina ◽  
Leonardo Abdala Elias ◽  
Stefano Nuccio ◽  
François Hug ◽  
...  
Keyword(s):  
Power Spectrum ◽  
Motor Unit ◽  
Population Level ◽  
Motor Units ◽  
Spatial Filtering ◽  
Surface Emg ◽  
Voluntary Contraction ◽  
Knee Extensors ◽  
Plantar Flexors ◽  
Emg Power Spectrum

Crosstalk is an important source of error in interpreting surface electromyography (EMG) signals. Here, we aimed at characterizing crosstalk for three groups of synergistic muscles by the identification of individual motor unit action potentials. Moreover, we explored whether spatial filtering (single and double differential) of the EMG signals influences the level of crosstalk. Three experiments were conducted. Participants (total twenty-five) performed isometric contractions at 10% of the maximal voluntary contraction (MVC) with digit muscles and knee extensors, and at 30% MVC with plantar flexors. High-density surface EMG signals were recorded and decomposed into motor unit spike trains. For each muscle, we quantified the crosstalk induced to neighboring muscles and the level of contamination by the nearby muscle activity. We also estimated the influence of crosstalk on the EMG power spectrum and intermuscular correlation. Most motor units (80%) generated significant crosstalk signals to neighboring muscle EMG in monopolar recording mode, but this proportion decreased with spatial filtering (50% and 42% for single and double differential, respectively). Crosstalk induced overestimations of intermuscular correlation and has a small effect on the EMG power spectrum, which indicates that crosstalk is not reduced with high-pass temporal filtering. Conversely, spatial filtering diminished the crosstalk magnitude and the overestimations of intermuscular correlation, confirming to be an effective and simple technique to reduce crosstalk. This paper presents a new method for the identification and quantification of crosstalk at the motor unit level and clarifies the influence of crosstalk on EMG interpretation for muscles with different anatomy.

Factors Governing the Form of the Relation Between Muscle Force and the EMG: A Simulation Study

2004 ◽  
Vol 92 (5) ◽  
pp. 2878-2886 ◽  
Author(s):  
Ping Zhou ◽  
William Zev Rymer
Keyword(s):  
Firing Rate ◽  
Motor Unit ◽  
Muscle Force ◽  
Dominant Role ◽  
Motor Units ◽  
Surface Emg ◽  
Emg Amplitude ◽  
Force Relation ◽  
Motor Unit Firing ◽  
Simulation Results

The dependence of the form of the EMG-force relation on key motoneuron and muscle properties was explored using a simulation approach. Surface EMG signals and isometric forces were simulated using existing motoneuron pool, muscle force, and surface EMG models, based primarily on reported properties of the first dorsal interosseous (FDI) muscle in humans. Our simulation results indicate that the relation between electrical and mechanical properties of the individual motor unit level plays the dominant role in determining the overall EMG amplitude-force relation of the muscle, while the underlying motor unit firing rate strategy appears to be a less important factor. However, different motor unit firing rate strategies result in substantially different relations between counts of the numbers of motoneuron discharges and the isometric force. Our simulation results also show that EMG amplitude (estimated as the average rectified value) increases as a result of synchronous discharges of different motor units within the pool, but the magnitude of this increase is determined primarily by the action potential duration of the synchronized motor units. Furthermore, when the EMG effects are normalized to their maximum levels, motor unit synchrony does not exert significant effects on the form of the EMG-force relation, provided that the synchrony level is held similar at different excitation levels.

scholarly journals Vastus Lateralis Motor Unit Firing Rate Is Higher in Women With Patellofemoral Pain

2018 ◽  
Vol 99 (5) ◽  
pp. 907-913 ◽  
Author(s):  
Alessio Gallina ◽  
Michael A. Hunt ◽  
Paul W. Hodges ◽  
S. Jayne Garland
Keyword(s):  
Firing Rate ◽  
Motor Unit ◽  
Vastus Lateralis ◽  
Patellofemoral Pain ◽  
Motor Unit Firing

scholarly journals Muscle vibration sustains motor unit firing rate during submaximal isometric fatigue in humans

2001 ◽  
Vol 535 (3) ◽  
pp. 929-936 ◽  
Author(s):  
L. Griffin ◽  
S. J. Garland ◽  
T. Ivanova ◽  
E. R. Gossen
Keyword(s):  
Firing Rate ◽  
Motor Unit ◽  
Muscle Vibration ◽  
Motor Unit Firing

On-Line Monitoring of the Median Frequency of the Surface EMG Power Spectrum

1985 ◽  
Vol BME-32 (1) ◽  
pp. 1-7 ◽  
Author(s):  
Roberto Merletti ◽  
Domenico Biey ◽  
Mario Biey ◽  
Giuseppe Prato ◽  
Andrea Orusa
Keyword(s):  
Power Spectrum ◽  
Surface Emg ◽  
Median Frequency ◽  
On Line ◽  
Emg Power Spectrum
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