Revised NIOSH Lifting Equation - Fundamentals and Assessment Tools for Occupational Ergonomics - page 873

VERTICAL

POINT OF
PROJECTION
HORIZONTAL

TOP VIEW

HORIZONTAL
LOCATION

H

LATERAL

MID-POINT BETWEEN
INNER ANKLE BONES

VERTICAL
LOCATION

V

HORIZONTAL

H

MID-POINT BETWEEN
INNER ANKLE BONES

POINT OF PROJECTION

HORIZONTAL
LOCATION

FIGURE 46.1 Graphic representation of hand location.

46.3 Limitations of Equation

The lifting equation is a tool for assessing the physical stress of two-handed manual lifting tasks. As with
any tool, its application is limited to those conditions for which it was designed. Specifically, the lifting
equation was designed to meet specific lifting-related criteria that encompass biomechanical, physiologi-
cal, and psychophysical assumptions and data used to develop the equation. To the extent that a given
lifting task accurately reflects these underlying conditions and criteria, this lifting equation may be
appropriately applied.
The following list identifies a set of work conditions inwhich the application of the lifting equation could
either underestimate or overestimate the extent of physical stress associated with a particular work-related
activity. Each of the following task limitations also highlights research topics in need of further research to
extend the application of the lifting equation to a greater range of real world lifting tasks.
The revised NIOSH lifting equation does not apply if any of the following occur:

. Lifting

lowering with one hand

/

. Lifting

lowering for over 8 h

/

. Lifting

lowering while seated or kneeling

/