Journal of the Ergonomics Society of Korea (대한인간공학회지)

Ergonomics Society of Korea (대한인간공학회)
권호 표지
DOI QR코드

DOI QR Code

Ergonomic Evaluation of Trunk-Forearm Support Type Chair

  • Lim, Seung Yeop (Gerontechnology R&D Center, Korea Institute of Industrial Technology) ;
  • Won, Byeong Hee (Gerontechnology R&D Center, Korea Institute of Industrial Technology)
  • Received : 2014.02.14
  • Accepted : 2014.03.25
  • Published : 2014.04.30
Download PDF
⟨ Previous Next ⟩

Abstract

Objective: The aim of this study is to investigate the effects of trunk-forearm supported sitting on trunk flexion angle, trunk extensor fatigue and seat contact pressure. Background: The relationship between sitting posture and musculoskeletal disorders of the trunk extensor fatigue and seat contact pressure has been documented. The trunk-forearm support type ergonomic chair was devised from the fact that trunk-forearm support has been reported to reduce trunk extensor activity and discomfort. Method: Using three different sitting postures, upright ($P_1$), trunk-forearm supported ($P_2$) and normal sitting ($P_3$), six healthy subjects participated in the study. Motion capture system was used to collect head and trunk flexion angle, and surface electromyography (sEMG) was used to collect myoelectric signal of upper trapezius, lower trapezius, erector spinae, multifidus, and pressure mat system was used to measure seat contact pressure. Results: When trunk and forearm were supported by the ergonomic chair, higher head flexion angle showed upright > trunk-forearm supported > normal in order, and muscle fatigue showed less than upright and normal sitting. Mean seat contact pressure decreased 19% than upright sitting. But muscle fatigue was not affected by each condition. Conclusion: Trunk-forearm supported sitting of the ergonomic chair showed positive effect in respect of trunk and head flexion angle, trunk extensor fatigue, seat contact pressure. To acquire comprehensive understanding of the effectiveness of the ergonomic chair, further studies such as anatomical effects from measurement of external applied loading effect to the body from interface pressure analysis are required. Application: The results of the publishing trend analysis might help physiological effects of trunk-forearm support type chair.

Keywords

References

  1. Cook, C., Burgess, L.R. and Papalis, S., "The effect of upper extremity support on upper extremity posture and muscle activity during keyboard use." Applied Ergonomics, 35, 285-292, 2004. https://doi.org/10.1016/j.apergo.2003.12.005
  2. Kong, Y.K., Lee, S.J., Lee, K.S. and Seo, M.T., "The effects of coordinated upper-limb postures of back, shoulder, and elbow flexion angles on the subjective discomfort rating, heart rate, and muscle activities." Journal Ergonomics Society Korea. 30(6), 695-703, 2011. https://doi.org/10.5143/JESK.2011.30.6.695
  3. Koo, J.W., "Occupational Disorders among Office Workers." Hanyang Medical Reviews, 30(4), 1738-429, 2010.
  4. Lee, Y.S., Park, S.C., Nam, Y.H., Kim, D.J. and Song, K.Y., "An ergonomic study on the design parameters for office chair." Journal of the Korea Furniture Society, 8(1), 17-28, 1997.
  5. Lee, E.C., "Association between job-stress and vdt work, and musculoskeletal symptoms of neck and shoulder among whitecollar workers." Korean Journal Occupation Environment Medicine, 19(3), 187-195, 2007.
  6. Mandal, A.C., "The seated man (homo sedens) the seated work position." Theory and Practice, Applied Ergonomics, 12, 19-26, 1981. https://doi.org/10.1016/0003-6870(81)90089-2
  7. Parent, T.A., Fernandes, M.E., Hurley, J. and Vermeylen, G., "Fourth European Working Conditions Survey." European Foundation for the Improvement of Living and Working Conditions, Dublin, 2007.
  8. Park, S.D., "Electomyographic activities of neck and shoulder muscle during the computer typing in forward head posture." The Graduate School of Health and Environment, Yonsei University, 2005.
  9. Song, Y.H., "Angular specificity of muscle fatigue and the transfer effect after isometric training of the vastus medialis." The Graduate School of Health and Environment, Yonsei University, 2006.
  10. Vink, P., "Comfort and design: Principles and good practice." CRCR press, Boca raton, 2005.
  11. Won, J.I., "Characteristics of the fatigue index in emg power spectrum analysis during isokinetic exercise." Korea Academy of University Trained Physical Therapists, 8(3), 11-26, 2001.