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Muscular rest and gap frequency as EMG measures of physical exposure: the impact of work tasks and individual related factors

Nordander, Catarina LU ; Hansson, Gert-Åke LU ; Rylander, Lars LU ; Asterland, P; Bystrom, J U; Ohlsson, Kerstina LU ; Balogh, Istvan LU and Skerfving, Staffan LU (2000) In Ergonomics 43(11). p.1904-1919
Abstract
Owing to an orderly recruitment of motor units, low threshold type I fibres are presumed to be vulnerable in contractions of long duration. To study load on these fibres muscular rest was registered as the time fraction of electromyographic (EMG) activity below a threshold. Moreover, the frequency of periods with muscular rest, EMG gaps, was derived, since a low gap frequency has been shown to be a risk factor for musculoskeletal disorders. Trapezius EMG was registered in 24 female hospital cleaners, 21 female office workers and 13 male office workers during one working day. Cleaners have a high risk of neck/shoulder pain and had much less muscular rest than office workers measured as a percentage of total registered time (median value =... (More)
Owing to an orderly recruitment of motor units, low threshold type I fibres are presumed to be vulnerable in contractions of long duration. To study load on these fibres muscular rest was registered as the time fraction of electromyographic (EMG) activity below a threshold. Moreover, the frequency of periods with muscular rest, EMG gaps, was derived, since a low gap frequency has been shown to be a risk factor for musculoskeletal disorders. Trapezius EMG was registered in 24 female hospital cleaners, 21 female office workers and 13 male office workers during one working day. Cleaners have a high risk of neck/shoulder pain and had much less muscular rest than office workers measured as a percentage of total registered time (median value = 1.5%, range = 0.2-13% vs. median value = 12%, range = 0.0-32%, respectively). Gap frequency showed no difference between the two occupational groups. Both measures displayed a wide inter-individual variation. For the cleaners, some of the variance was explained by body mass index (BMI) and age, with lower values of muscular rest for older subjects with a high BMI. Among the office workers, low values of muscular rest and a high gap frequency were registered in subjects with a low subjective muscular tension tendency. Gender, strength, smoking, job strain, employment time and musculoskeletal symptoms had no impact on either EMG measure. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Ergonomics
volume
43
issue
11
pages
1904 - 1919
publisher
Taylor & Francis
external identifiers
  • pmid:11105979
  • scopus:0033750345
ISSN
0014-0139
DOI
10.1080/00140130050174536
language
English
LU publication?
yes
id
fd5e990a-5810-4739-b232-da492ff676e5 (old id 1118438)
date added to LUP
2008-06-16 15:45:01
date last changed
2017-07-02 03:47:20
@article{fd5e990a-5810-4739-b232-da492ff676e5,
  abstract     = {Owing to an orderly recruitment of motor units, low threshold type I fibres are presumed to be vulnerable in contractions of long duration. To study load on these fibres muscular rest was registered as the time fraction of electromyographic (EMG) activity below a threshold. Moreover, the frequency of periods with muscular rest, EMG gaps, was derived, since a low gap frequency has been shown to be a risk factor for musculoskeletal disorders. Trapezius EMG was registered in 24 female hospital cleaners, 21 female office workers and 13 male office workers during one working day. Cleaners have a high risk of neck/shoulder pain and had much less muscular rest than office workers measured as a percentage of total registered time (median value = 1.5%, range = 0.2-13% vs. median value = 12%, range = 0.0-32%, respectively). Gap frequency showed no difference between the two occupational groups. Both measures displayed a wide inter-individual variation. For the cleaners, some of the variance was explained by body mass index (BMI) and age, with lower values of muscular rest for older subjects with a high BMI. Among the office workers, low values of muscular rest and a high gap frequency were registered in subjects with a low subjective muscular tension tendency. Gender, strength, smoking, job strain, employment time and musculoskeletal symptoms had no impact on either EMG measure.},
  author       = {Nordander, Catarina and Hansson, Gert-Åke and Rylander, Lars and Asterland, P and Bystrom, J U and Ohlsson, Kerstina and Balogh, Istvan and Skerfving, Staffan},
  issn         = {0014-0139},
  language     = {eng},
  number       = {11},
  pages        = {1904--1919},
  publisher    = {Taylor & Francis},
  series       = {Ergonomics},
  title        = {Muscular rest and gap frequency as EMG measures of physical exposure: the impact of work tasks and individual related factors},
  url          = {http://dx.doi.org/10.1080/00140130050174536},
  volume       = {43},
  year         = {2000},
}