Document Detail


Myoelectric signal measurement during prolonged computer terminal work.
MedLine Citation:
PMID:  10659448     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Myoelectric signal (MES) behaviour was studied during prolonged, sustained, low level contractions using a portable system with limited data storage capacity. A pre-processing technique is described which overcomes memory and data storage limitations in a portable multichannel MES data logger. This technique for data reduction was used to study MES behaviour in four muscle groups during prolonged computer terminal work. Myoelectric signal parameters were recorded from eighteen individuals while they performed computer work both without breaks, and with "microbreaks" (short rest breaks of 30 seconds duration) at twenty minute intervals. Myoelectric signal (MES) data were collected from the cervical paraspinal extensors, the lumbar erector spinae, the upper trapezius, and the forearm extensors while participants performed their usual computer work activities. No significant slope for either amplitude or mean frequency was determined in either the break or no break trials over an eighty minute recording period. Instead, most data sets revealed a cyclic trend in terms of frequency and amplitude parameters of the MES. Characteristic values were compared between trials when subjects did and did not take microbreaks. It was found that the overall median value of mean frequency was higher for the "break" than the "no break" protocol only in the cervical extensors, although the clinical significance of this finding is not well understood. By far, the most interesting finding of this work was the discovery of a cyclic trend in the mean frequency of the myoelectric signals studied. This trend was present even when participants did not take breaks. The trend is a potential indicator of the cyclic recruitment of motor units during sustained postural contractions, and is the primary area to be investigated in future studies by the authors.
Authors:
L McLean; M Tingley; R N Scott; J Rickards
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Journal of electromyography and kinesiology : official journal of the International Society of Electrophysiological Kinesiology     Volume:  10     ISSN:  1050-6411     ISO Abbreviation:  J Electromyogr Kinesiol     Publication Date:  2000 Feb 
Date Detail:
Created Date:  2000-02-15     Completed Date:  2000-02-15     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  9109125     Medline TA:  J Electromyogr Kinesiol     Country:  ENGLAND    
Other Details:
Languages:  eng     Pagination:  33-45     Citation Subset:  IM    
Affiliation:
Dalhousie University School of Physiotherapy, Halifax, NS, Canada. linda.mclean@dal.ca
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MeSH Terms
Descriptor/Qualifier:
Arm
Back
Computer Terminals*
Humans
Muscle Contraction*
Muscle, Skeletal / physiopathology*

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


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