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. 2019 Jul;10(3):137-144.
doi: 10.15171/ijoem.2019.1551.

Myoelectric Activity of Individual Lumbar Erector Spinae Muscles Variation by Differing Seat Pan Depth

Mahmood Reza Azghani  1 , Jalil Nazari  2 , Nader Sozapoor  3 , Mohamad Asghari Jafarabadi  4 , Ali E Oskouei  5
Affiliations

Myoelectric Activity of Individual Lumbar Erector Spinae Muscles Variation by Differing Seat Pan Depth

Mahmood Reza Azghani et al. Int J Occup Environ Med. 2019 Jul.

Abstract

Background: The chair influences the position of the user in relation to his or her devices. Prolonged static sitting is a frequently mentioned risk factor for low back pain. Seat design, thus, plays an important role in the study of human sitting. Quantitative information is needed on what happens to body when one sits in chairs with different seat depth.

Objective: To determine the myoelectric activity (EMG) of individual lumbar erector spinae muscles after sitting in chairs with different seat pan depth.

Methods: EMG recordings were taken using surface electrodes placed on the lumbar erector spine muscles of 25 normal, volunteer subjects. EMG recordings for muscle activity were made while the study participants were in a comfortable position and performed the required tasks. The experiments investigated with 3 seat depths according to the 5th, 50th and 95th percentiles of the buttock popliteal length. The recorded EMG data were normalized to the maximal voluntary contraction. The mean EMG recording was calculated for each of the 3 chairs tested. A mixed model was used to assess the differences among the situations.

Results: A significant (p<0.05) difference was observed between the mean EMG recordings for the 3 tested seat pan depths. EMG activity was higher in seats with the 5th and 95th percentiles compared with that for the seat with 50th percentile of buttock popliteal length depth.

Conclusion: The seat pan depth used during a comfortable position has a significant effect on the level of myoelectric activity in the lumbar erector spinal muscles. The finding of this study may contribute to our understanding of the biomechanics of sitting.

Keywords: Anthropometry; Electromyography; Ergonomics; Fatigue; Muscles.

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Conflict of interest statement

None declared.

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References

    1. Jung J Y, Park I S, Won Y, et al. Development of a system for measurement on asymmetric sitting posture. International Conference on Biology, Medical Physics, Medical Chemistry, Biochemistry and Biomedical Engineering. 2013.
    1. Toomingas A, Forsman M, Mathiassen SE. et al. Variation between seated and standing/walking postures among male and female call centre operators. BMC Public Health. 2012;12:154. - PMC - PubMed
    1. Katzmarzyk PT1, Church TS, Craig CL, Bouchard C. Sitting Time and mortality from all causes, cardiovascular disease, and cancer. Med Sci Sports Exerc. 2009;41:998–1005. - PubMed
    1. Morl F, Bradl I. Lumbar posture and muscular activity while sitting during office work. J Electromyogr Kinesiol. 2013;23:362–8. - PubMed
    1. Gerr F, Marcus M, Monteilh C. Epidemiology of musculoskeletal disorders among computer users: Lesson learned from the role of posture and keyboard use. J Electromyogr Kinesiol. 2004;14:25–31. - PubMed

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