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Sensitivity of trapezius electromyography to differences between work tasks - influence of gap definition and normalisation methods

Hansson, Gert-Åke LU ; Nordander, Catarina LU ; Asterland, P; Ohlsson, Kerstina LU ; Strömberg, Ulf LU ; Skerfving, Staffan LU and Rempel, D (2000) In Journal of Electromyography & Kinesiology 10(2). p.103-115
Abstract
Surface electromyography (EMG) has been used extensively to estimate muscular load in studies of work related musculoskeletal disorders, especially for the trapezius muscle. The occurrences of periods of EMG silence (gaps), the time below a predetermined threshold level (muscular rest) and various percentiles of the amplitude distribution (APDF) are commonly used summary measures. However, the effects of the criteria used to calculate these measures (e.g., gap duration, threshold level, normalisation method) on the sensitivity of these measures to accurately differentiate work loads is not well known.Bilateral trapezius EMG was recorded, for a full workday, for 58 subjects following both maximal (MVE) and submaximal (RVE) reference... (More)
Surface electromyography (EMG) has been used extensively to estimate muscular load in studies of work related musculoskeletal disorders, especially for the trapezius muscle. The occurrences of periods of EMG silence (gaps), the time below a predetermined threshold level (muscular rest) and various percentiles of the amplitude distribution (APDF) are commonly used summary measures. However, the effects of the criteria used to calculate these measures (e.g., gap duration, threshold level, normalisation method) on the sensitivity of these measures to accurately differentiate work loads is not well known.Bilateral trapezius EMG was recorded, for a full workday, for 58 subjects following both maximal (MVE) and submaximal (RVE) reference contractions. Gap frequency, muscular rest, and percentiles were derived for eight fundamental work tasks. The calculations were performed using different gap duration criteria, threshold levels and normalisation methods.A gap duration of less than 1/2 s, and threshold level approximately 0.3% MVE for gap frequency, and approximately 0.5% MVE for muscular rest, were the criteria that optimised sensitivity to task differences. Minimal sensitivity to tasks and a high sensitivity to individuals was obtained using gap frequency with a threshold level of approximately 1% MVE. Normalisation to RVE, rather than MVE, improved sensitivity to differences between tasks, and reduced undesirable variability. Muscular rest was more sensitive to task differences than APDF percentiles. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Journal of Electromyography & Kinesiology
volume
10
issue
2
pages
103 - 115
publisher
Elsevier
external identifiers
  • pmid:10699558
  • scopus:0033953378
ISSN
1873-5711
DOI
10.1016/S1050-6411(99)00030-9
language
English
LU publication?
yes
id
605e2384-195c-4fbf-b176-777ed8a65357 (old id 1118446)
date added to LUP
2008-06-16 15:48:45
date last changed
2017-08-20 03:34:44
@article{605e2384-195c-4fbf-b176-777ed8a65357,
  abstract     = {Surface electromyography (EMG) has been used extensively to estimate muscular load in studies of work related musculoskeletal disorders, especially for the trapezius muscle. The occurrences of periods of EMG silence (gaps), the time below a predetermined threshold level (muscular rest) and various percentiles of the amplitude distribution (APDF) are commonly used summary measures. However, the effects of the criteria used to calculate these measures (e.g., gap duration, threshold level, normalisation method) on the sensitivity of these measures to accurately differentiate work loads is not well known.Bilateral trapezius EMG was recorded, for a full workday, for 58 subjects following both maximal (MVE) and submaximal (RVE) reference contractions. Gap frequency, muscular rest, and percentiles were derived for eight fundamental work tasks. The calculations were performed using different gap duration criteria, threshold levels and normalisation methods.A gap duration of less than 1/2 s, and threshold level approximately 0.3% MVE for gap frequency, and approximately 0.5% MVE for muscular rest, were the criteria that optimised sensitivity to task differences. Minimal sensitivity to tasks and a high sensitivity to individuals was obtained using gap frequency with a threshold level of approximately 1% MVE. Normalisation to RVE, rather than MVE, improved sensitivity to differences between tasks, and reduced undesirable variability. Muscular rest was more sensitive to task differences than APDF percentiles.},
  author       = {Hansson, Gert-Åke and Nordander, Catarina and Asterland, P and Ohlsson, Kerstina and Strömberg, Ulf and Skerfving, Staffan and Rempel, D},
  issn         = {1873-5711},
  language     = {eng},
  number       = {2},
  pages        = {103--115},
  publisher    = {Elsevier},
  series       = {Journal of Electromyography & Kinesiology},
  title        = {Sensitivity of trapezius electromyography to differences between work tasks - influence of gap definition and normalisation methods},
  url          = {http://dx.doi.org/10.1016/S1050-6411(99)00030-9},
  volume       = {10},
  year         = {2000},
}