Characterization of the dynamics of sitting during a sustained and mentally demanding computer task

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Abstract

This laboratory study studied the dynamics of sitting during a sustained and mentally demanding computer task. Mental fatigue ratings, overall performance and kinetic were recorded in 20 asymptomatic computer users performing computer work for 40 min divided in 12 time epochs. The displacement of the center of pressure (COP) in anterior-posterior (AP) and medial-lateral (ML) directions was calculated. The average, standard deviation, and sample entropy values were computed from the COP time series to assess respectively, the magnitude, size and complexity of sitting dynamics. Fatigue ratings significantly increased from before to after the computer task while the overall performance did not change significantly over time. Likewise, the direction of displacement of the COP did not affect significantly the AVG but resulted in larger SD and SaEn values in the ML direction compared with AP direction. Time did not play a significant role on any of the outcome measures. The present study demonstrated that the sitting dynamics can be assessed in an ecological environment, e.g. in office chairs. Further, we found that 40 min seated computer work did not changed the dynamics of sitting. On the contrary, we observed increased size and structure of variability in the ML than the AP direction. This latter finding can be used to design office chairs or interventions aiming at preventing discomfort due to long time sitting.

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This laboratory study studied the dynamics of sitting during a sustained and mentally demanding computer task. Mental fatigue ratings, overall performance and kinetic were recorded in 20 asymptomatic computer users performing computer work for 40 min divided in 12 time epochs. The displacement of the center of pressure (COP) in anterior-posterior (AP) and medial-lateral (ML) directions was calculated. The average, standard deviation, and sample entropy values were computed from the COP time series to assess respectively, the magnitude, size and complexity of sitting dynamics. Fatigue ratings significantly increased from before to after the computer task while the overall performance did not change significantly over time. Likewise, the direction of displacement of the COP did not affect significantly the AVG but resulted in larger SD and SaEn values in the ML direction compared with AP direction. Time did not play a significant role on any of the outcome measures. The present study demonstrated that the sitting dynamics can be assessed in an ecological environment, e.g. in office chairs. Further, we found that 40 min seated computer work did not changed the dynamics of sitting. On the contrary, we observed increased size and structure of variability in the ML than the AP direction. This latter finding can be used to design office chairs or interventions aiming at preventing discomfort due to long time sitting.

Original languageEnglish
Title of host publicationProceedings of the 20th Congress of the International Ergonomics Association, IEA 2018 : Volume VII: Ergonomics in Design, Design for All, Activity Theories for Work Analysis and Design, Affective Design
EditorsSebastiano Bagnara, Riccardo Tartaglia, Sara Albolino, Thomas Alexander, Yushi Fujita
Number of pages7
PublisherSpringer
Publication date2019
Pages338-344
ISBN (Print)978-3-319-96070-8
ISBN (Electronic)978-3-319-96071-5
DOI
Publication statusPublished - 2019
Publication categoryResearch
Peer-reviewedYes
Event20th Congress of the International Ergonomics Association, IEA 2018 - Florence, Italy
Duration: 26 Aug 201830 Aug 2018

Conference

Conference20th Congress of the International Ergonomics Association, IEA 2018
LandItaly
ByFlorence
Periode26/08/201830/08/2018
SeriesAdvances in Intelligent Systems and Computing
Volume824
ISSN2194-5357

    Research areas

  • Nonlinear dynamics, Sitting control, Variability
ID: 284362009