Pg. Dempsey et Fa. Fathallah, Application issues and theoretical concerns regarding the 1991 NIOSH equation asymmetry multiplier, INT J IND E, 23(3), 1999, pp. 181-191
The lifting equation developed by the National Institute for Occupational S
afety and Health in 1981 was revised in 1991. One goal of the revision was
to accommodate non-sagittal lifting tasks, since sagittal lifting tasks are
an exception rather than the rule in many industrial settings. This goal o
f expanding the equation to non-sagittal tasks was accomplished by adding a
n asymmetry multiplier to the lifting equation. This paper examines the rat
ionale behind the development of the asymmetry multiplier and provides an a
lternative perspective by reviewing additional literature. The usability of
the asymmetry multiplier in industry is discussed with particular emphasis
on the applications manual for the 1991 NIOSH equation. The concept of ope
rational definitions required to be able to use the equation as intended is
presented. Data from three different sources illustrate the problems and v
ariability associated with measuring asymmetry, as required by the NIOSH eq
uation, in industrial settings. Finally, recommendations for further resear
ch and potential modifications to the asymmetry multiplier are presented.
Relevance to industry
The discussion of measuring asymmetry in industry has particular relevance
to industrial settings where the NIOSH equation is applied and asymmetry mu
st be measured. (C) 1999 Elsevier B.V. All rights reserved.