umu.sePublications
Change search
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Spatial distribution of active muscle fibre characteristics in the upper trapezius muscle and its dependency on contraction level and duration
Umeå University, Faculty of Science and Technology, Centre for Biomedical Engineering and Physics (CMTF). Department of Biomedical Engineering and Informatics, University Hospital, Umeå, Sweden.
Umeå University, Faculty of Science and Technology, Centre for Biomedical Engineering and Physics (CMTF). Department of Biomedical Engineering and Informatics, University Hospital, Umeå, Sweden.
2008 (English)In: Journal of Electromyography & Kinesiology, ISSN 1050-6411, E-ISSN 1873-5711, Vol. 18, no 3, p. 372-381Article in journal (Refereed) Published
Abstract [en]

The aim of this study was to provide direct in vivo information of the physiological and structural characteristics of active muscle fibres from a large part of the upper trapezius muscle. Two-dimensional (2-D) multi-channel surface electromyography recordings were used, with 13 × 10 electrodes covering 6 × 4.5 cm of the skin’s surface. A previously developed method was applied to detect individual propagating motor unit action potentials and to estimate their corresponding muscle fibre conduction velocity (MFCV) and muscle fibre orientation (MFO). Using these estimates, spatial distributions of MFCV and MFO were examined for five male subjects performing isometric shoulder elevation at different force levels. The main results were: (1) the general relationship between MFCV and force generation was non-systematic, with a positive relationship at the inferior part of the muscle, (2) the spatial distribution of MFCV at different force levels and fatigue was inhomogeneous and (3) the MFO was slightly different (6°) of the muscle fibres with origin superior compared to inferior to the C7 vertebra. These findings provide new information of the MFO of contracting muscle fibres and knowledge of the physiological characteristics of a large part of the upper trapezius muscle that previously was based on observations from human cadavers only.

Place, publisher, year, edition, pages
Elsevier, 2008. Vol. 18, no 3, p. 372-381
Keywords [en]
Muscle fibre conduction velocity, muscle architecture, inhomogeneous activation, multi-channel surface EMG, fatigue
National Category
Neurology
Identifiers
URN: urn:nbn:se:umu:diva-10002DOI: 10.1016/j.jelekin.2006.12.003ISI: 000256600400003PubMedID: 17276698OAI: oai:DiVA.org:umu-10002DiVA, id: diva2:149673
Available from: 2008-06-04 Created: 2008-06-04 Last updated: 2020-01-23Bibliographically approved
In thesis
1. Spatio-temporal processing of surface electromyographic signals: information on neuromuscular function and control
Open this publication in new window or tab >>Spatio-temporal processing of surface electromyographic signals: information on neuromuscular function and control
2006 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

During muscle contraction, electrical signals are generated by the muscle cells. The analysis of those signals is called electromyography (EMG). The EMG signal is mainly determined by physiological factors including so called central factors (central nervous system origin) and peripheral factors (muscle tissue origin). In addition, during the acquisition of EMG signals, technical factors are introduced (measurement equipment origin). The aim of this dissertation was to develop and evaluate methods to estimate physiological properties of the muscles using multichannel surface EMG (MCsEMG) signals.

In order to obtain accurate physiological estimates, a method for automatic signal quality estimation was developed. The method’s performance was evaluated using visually classified signals, and the results demonstrated high classification accuracy.

A method for estimation of the muscle fibre conduction velocity (MFCV) and the muscle fibre orientation (MFO) was developed. The method was evaluated with synthetic signals and demonstrated high estimation precision at low contraction levels.

In order to discriminate between the estimates of MFCV and MFO belonging to single or populations of motor units (MUs), density regions of so called spatial distributions were examined. This method was applied in a study of the trapezius muscle and demonstrated spatial separation of MFCV (as well as MFO) even at high contraction levels.

In addition, a method for quantification of MU synchronisation was developed. The performance on synthetic sEMG signals showed high sensitivity on MU synchronisation and robustness to changes in MFCV. The method was applied in a study of the biceps brachii muscle and the relation to force tremor during fatigue. The results showed that MU synchronisation accounted for about 40 % of the force tremor.

In conclusion, new sEMG methods were developed to study muscle function and motor control in terms of muscle architecture, muscle fibre characteristics, and processes within the central nervous system.

Place, publisher, year, edition, pages
Umeå: Umeå universitet, 2006. p. 97
Series
Umeå University medical dissertations, ISSN 0346-6612 ; 1078
Keywords
EMG, multichannel surface electromyography, motor unit action potentials, conduction velocity, muscle architecture, signal quality, spatial distributions, synchronization, muscle function, motor control
National Category
Medical Engineering
Research subject
Biomedical Radiation Science
Identifiers
urn:nbn:se:umu:diva-958 (URN)978-91-7264-239-3 (ISBN)91-7264-239-4 (ISBN)
Public defence
2007-01-12, Lionssalen (sal 244), 7, NUS, Umeå, 13:00 (English)
Opponent
Available from: 2006-12-22 Created: 2006-12-22 Last updated: 2018-06-09Bibliographically approved

Open Access in DiVA

No full text in DiVA

Other links

Publisher's full textPubMed

Authority records BETA

Grönlund, ChristerKarlsson, Stefan

Search in DiVA

By author/editor
Grönlund, ChristerKarlsson, Stefan
By organisation
Centre for Biomedical Engineering and Physics (CMTF)
In the same journal
Journal of Electromyography & Kinesiology
Neurology

Search outside of DiVA

GoogleGoogle Scholar

doi
pubmed
urn-nbn

Altmetric score

doi
pubmed
urn-nbn
Total: 151 hits
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf