The influence of contraction type, prior performance of a maximal voluntary contraction and measurement duration on fine-wire EMG amplitude.
J Electromyogr Kinesiol
; 59: 102566, 2021 Aug.
Article
in English
| MEDLINE | ID: covidwho-1260782
ABSTRACT
We aimed to investigate the impact of time on fine-wire (fw) electromyography (EMG) signal amplitude, and to determine whether any attenuation is confounded by task type. Twenty healthy participants were instrumented with fw and surface (s) EMG electrodes at the biceps brachii bilaterally. Participants held a weight statically with one arm and with the other arm either repeated the same task following a maximum voluntary contraction (MVC) or repeated dynamic elbow flexion/extension contractions. Each task was repeated for 30 s every five minutes over two hours. EMG amplitude was smoothed and normalized to time = 0. Stable median power frequency of the s-EMG ruled out the confounding influence of fatigue. Repeated-measures ANCOVAs determined the effect of electrode type and time (covariate) on EMG amplitude and the confounding impact of task type. During the isometric protocol, fw-EMG amplitude reduced over time (p = 0.002), while s-EMG amplitude (p = 0.895) and MPF (p > 0.05) did not change. Fw-EMG amplitude attenuated faster during the dynamic than the isometric protocol (p = 0.008) and there was evidence that the MVC preceding the isometric protocol impacted the rate of decline (p = 0.001). We conclude that systematic signal attenuation of fw-EMG occurs over time and is more pronounced during dynamic tasks.
Keywords
Full text:
Available
Collection:
International databases
Database:
MEDLINE
Main subject:
Elbow Joint
/
Isometric Contraction
Type of study:
Systematic review/Meta Analysis
Limits:
Humans
Language:
English
Journal:
J Electromyogr Kinesiol
Journal subject:
Physiology
Year:
2021
Document Type:
Article
Affiliation country:
J.jelekin.2021.102566
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