The backrest on a working seat reduces back muscle tension and the need to lock the spine for the transmission of horizontal forces from the trunk to the chair. These effects reduce inter-vertebral compression forces, which cause the discs to collapse. A simple and precise method for measuring shrinkage in stature has been developed and used to examine variations in the design of seats. The findings are discussed in relation to the biomechanics of sitting, and conclusions for seat design presented.
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References
1.
ÅkerblomB.Chairs and sitting. In FloudW.F.WelfordA.T. (Eds.) Human factors in equipment design. H.K. Lewis & Co Ltd., London, 1954.
2.
AnderssonG.B.J.ÖrtengrenR.SchultzA.Analysis and measurement of the loads on the lumbar spine during work at a table. Journal of Biomechanics, 1980, 13, 513–520.
3.
BurnsM.L.KalepsI.Analysis of load-deflection behaviour of intervertebral discs under axial compression using exact parametric solution of Kelvin-solid models. Journal of Biomechanics, 1980, 13, 959–964.
4.
CorlettE.N.EklundJ.A.E.How does a backrest work?Applied Ergonomics, 1983 (accepted for publication).
5.
EklundJ.A.E.CorlettE.N.Shrinkage as a measure of the effect of load on the spine. Spine, 1983 (accepted for publication).
6.
EklundJ.A.E.CorlettE.N.JohnsonF.A method for measuring the load imposed on the back of a sitting person. Ergonomics, 1983 (in press).
7.
KeeganJ.J.Alterations of the lumbar curve related to posture and seating. Journal of Bone and Joint Surgery, 1953, 35A, 3, 589–603.
