Document Detail

The behaviour of the mean power frequency of the surface electromyogram in biceps brachii with increasing force and during fatigue. With special regard to the electrode distance.
MedLine Citation:
PMID:  2286173     Owner:  NLM     Status:  MEDLINE    
The present study aims to investigate: a) the relationship between force and mean power frequency of the EMG, and b) how the distance between surface electrodes influences the mean power frequency. The study consisted of three parts: 1) a gradually increasing contraction upto 100% MVC, 2) contractions performed at 5 different levels from 20% upto 100% MVC with rest in between, and 3) an endurance test at 30% MVC. Nine healthy women participated. The elbow was flexed 90 degrees and EMG signals were obtained from the biceps brachii. The surface electrodes were placed so that electrode distances of 10 mm, 20 mm and 30 mm were obtained. The mean power frequency increased upto 60% MVC. Above 60% MVC no change in mean power frequency occurred. No differences in the mean power frequency with respect to the electrode distances existed at each force level. No significant differences were found at each contraction level between the gradually increasing contraction and the stepwise increasing contractions. The mean power frequency decreased linearly during the endurance test without any differences with respect to the electrode distances. It is concluded that the different electrode distances do not affect the mean power frequency-force relationship or the decrease in mean power frequency during fatigue. It is proposed that the increase in mean power frequency, on group level, can be used as an indicator of motor unit recruitment. However, this proposal was found to be complicated when individual analyses were made.
B Gerdle; N E Eriksson; L Brundin
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Publication Detail:
Type:  Journal Article    
Journal Detail:
Title:  Electromyography and clinical neurophysiology     Volume:  30     ISSN:  0301-150X     ISO Abbreviation:  Electromyogr Clin Neurophysiol     Publication Date:  1990 Dec 
Date Detail:
Created Date:  1991-03-22     Completed Date:  1991-03-22     Revised Date:  2004-11-17    
Medline Journal Info:
Nlm Unique ID:  0327533     Medline TA:  Electromyogr Clin Neurophysiol     Country:  BELGIUM    
Other Details:
Languages:  eng     Pagination:  483-9     Citation Subset:  IM    
National Institute of Occupational Health, Work Physiology Unit, Umeå, Sweden.
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MeSH Terms
Muscle Contraction / physiology
Muscles / physiology*
Time Factors

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

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