Author :
Christensen, Hanne
Author_Institution :
Nat. Inst. of Occupational Health, Copenhagen, Denmark
Abstract :
The author reviews the use of electromyography (EMG) to register the activity pattern and work load in the muscles during occupational work. For repetitive monotonous work the static activity level in the trapezius, infraspinatus and deltoid muscles are 8-20% (maximal voluntary contraction) (MVC), and the mean activity levels are 13-30% MVC; the EMG does not change during a working day. Muscle fatigue is registrated for isometric contractions at low force levels (10% MVC) and shows an increase in the amplitude (95%) and a simultaneous decrease in the mean power frequency of the power spectrum of the EMG (25%). The changes are attributed to higher firing rates, a higher degree of synchronization of active motor units, and new recruitment
Keywords :
bioelectric potentials; muscle; waveform analysis; EMG power spectrum; active motor units synchronisation; deltoid; electromyography; firing rate; infraspinatus; isometric contractions; maximal voluntary contraction; muscle activity pattern; muscle fatigue; muscle work load; occupational work; repetitive monotonous work; static activity level; trapezius; Biomembranes; Electrodes; Electromyography; Fatigue; Frequency measurement; Frequency synchronization; Hafnium; Muscles; Occupational health; Recruitment;
Conference_Titel :
Engineering in Medicine and Biology Society, 1989. Images of the Twenty-First Century., Proceedings of the Annual International Conference of the IEEE Engineering in
Conference_Location :
Seattle, WA
DOI :
10.1109/IEMBS.1989.96292
