Cescon, Corrado and Sguazzi, Elena and Merletti, Roberto and Farina, Dario (2006) Non-invasive characterization of single motor unit electromyographic and mechanomyographic activities in the biceps brachii muscle. Journal of Electromyography and Kinesiology, 16 (1). pp. 17-24. ISSN 1050-6411
Full text not available from this repository.Abstract
The aim of the study was to investigate amplitude and frequency content of single motor unit (MU) electromyographic (EMG) and mechanomyographic (MMG) responses. Multi-channel surface EMG and MMG signals were detected from the dominant biceps brachii muscle of 10 volunteers during isometric voluntary contractions at 20%, 50%, and 80% of the maximal voluntary contraction (MVC) force. Each contraction was performed three times in the experimental session which was repeated in three non-consecutive days. Single MU action potentials were identified from the surface EMG signals and their times of occurrence used to trigger the averaging of the MMG signal. At each contraction level, the MUs with action potentials of highest amplitude were identified. Single MU EMG and MMG amplitude and mean frequency were estimated with normalized standard error of the mean within subjects (due to repetition of the measure in different trials and experimental sessions) smaller than 15% and 7%, respectively, in all conditions. The amplitude of the action potentials of the detected MUs increased with increasing force (mean +/- SD, 244 +/- 116 microV at 20% MVC, and 1426 +/- 638 microV at 80% MVC; P < 0.001) while MU MMG amplitude increased from 20% to 50% MVC (40.5 +/- 20.9 and 150 +/- 88.4 mm/s(2), respectively; P<0.001) and did not change significantly between 50% and 80% MVC (129 +/ -82.7 mm/s(2) at 80% MVC). MU EMG mean frequency decreased with contraction level (20% MVC: 97.2 +/- 13.9 Hz; 80% MVC: 86.2 +/- 11.4 Hz; P < 0.001) while MU MMG mean frequency increased (20% MVC: 33.2 +/- 6.8 Hz; 80% MVC: 40.1 +/- 6.1 Hz; P < 0.001). EMG peak-to-peak amplitude and mean frequency of individual MUs were not correlated with the corresponding variables of MMG at any contraction level.
| Item Type: | Scientific journal article, Newspaper article or Magazine article |
|---|---|
| Uncontrolled Keywords: | Action Potentials, Adult, Arm, Biomechanics, Electromyography, Humans, Isometric Contraction,Male, Motor Neurons, Motor Neurons: physiology, Muscle, Skeletal, Muscle, Skeletal: physiology |
| Subjects: | Engineering > General engineering > Bioengineering, biomedical engineering & clinical engineering |
| Department/unit: | Dipartimento economia aziendale, sanità e sociale > Laboratorio di ricerca in riabilitazione |
| Depositing User: | Corrado Cescon |
| Date Deposited: | 13 Sep 2013 10:06 |
| Last Modified: | 14 May 2021 11:00 |
| URI: | http://repository.supsi.ch/id/eprint/2742 |
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