The influence of contraction type, prior performance of a maximal voluntary contraction and measurement duration on fine-wire EMG amplitude
| Autor: | Linda McLean, Joanna Reeves |
|---|---|
| Rok vydání: | 2021 |
| Předmět: |
medicine.medical_specialty
Contraction (grammar) medicine.diagnostic_test Muscle fatigue Electromyography business.industry Biophysics Neuroscience (miscellaneous) Isometric exercise EMG amplitude musculoskeletal system Biceps body regions Amplitude Physical medicine and rehabilitation Duration (music) Isometric Contraction Elbow Joint medicine Humans Neurology (clinical) Range of Motion Articular Muscle Skeletal business |
| Zdroj: | Journal of Electromyography and Kinesiology. 59:102566 |
| ISSN: | 1050-6411 |
| DOI: | 10.1016/j.jelekin.2021.102566 |
| Popis: | 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. |
| Databáze: | OpenAIRE |
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