Trapezius muscle activity increases during near work activity regardless of accommodation/vergence demand level
2015 (English)In: European Journal of Applied Physiology, ISSN 1439-6319, E-ISSN 1439-6327, Vol. 115, no 7, 1501-1512 p.Article in journal (Refereed) Published
To investigate if trapezius muscle activity increases over time during visually demanding near work. The vision task consisted of sustained focusing on a contrast-varying black and white Gabor grating. Sixty-six participants with a median age of 38 (range 19-47) fixated the grating from a distance of 65 cm (1.5 D) during four counterbalanced 7-min periods: binocularly through -3.5 D lenses, and monocularly through -3.5 D, 0 D and +3.5 D. Accommodation, heart rate variability and trapezius muscle activity were recorded in parallel. General estimating equation analyses showed that trapezius muscle activity increased significantly over time in all four lens conditions. A concurrent effect of accommodation response on trapezius muscle activity was observed with the minus lenses irrespective of whether incongruence between accommodation and convergence was present or not. Trapezius muscle activity increased significantly over time during the near work task. The increase in muscle activity over time may be caused by an increased need of mental effort and visual attention to maintain performance during the visual tasks to counteract mental fatigue.
Place, publisher, year, edition, pages
2015. Vol. 115, no 7, 1501-1512 p.
Attention fatigue, Accommodation, Bekesy test, Compensatory effort, Contrast threshold tracking, Electromyography, Visual ergonomics
Environmental Health and Occupational Health
IdentifiersURN: urn:nbn:se:uu:diva-256983DOI: 10.1007/s00421-015-3125-9ISI: 000355872200011PubMedID: 25697148OAI: oai:DiVA.org:uu-256983DiVA: diva2:838692