SJWEH Supplements are open access, (mostly) non-peer-reviewed articles usually published in theme issues or as part of a series of papers from a conference or workshop. Scand J Work Environ Health stopped publishing SJWEH Supplements in 2009.


SJWEH Supplements 2007;(no 3):76-80    pdf

Trapezius muscle tone and viscoelastic properties in sitting and supine positions

by Viir R, Virkus A, Laiho K, Rajaleid K, Selart A, Mikkelsson M

Objectives In this study, the aim was to use the upper trapezius muscle as a representative of the musculoskeletal support system to determine the effect of changing from a sitting position to a lying position on muscle tension and whether this change could be useful in the prevention of musculoskeletal complaints.

Methods Fifteen healthy right-handed female computer operators participated in this study. Myometric measurements of the upper trapezius muscle on both sides of the body were recorded for the participants while they were in a sitting position and then again in a supine position.

Results Changing from a sitting position to a supine position reduced the tone and stiffness by up to one-fifth—important characteristics of the support function—in the upper trapezius muscle.

Conclusions The change in the tone and stiffness of the trapezius muscle is of significance to the well-being of sedentary workers, particularly computer-terminal operators. Including recommended regular breaks of brief periods of simple, unchallenging movements while in a supine position should enhance their recovery from prolonged sitting because the support requirement on the muscles is lessened.