Low Back Injury Risk Assessment Tools - Fundamentals and Assessment Tools for Occupational Ergonomics - page 685

35
Low Back Injury Risk
Assessment Tools

35.1 Introduction .............................. 35-1
35.2 NIOSH Lifting Equations .................... 35-1
35.3 LMM Risk Assessment Model . . ............... 35-2
35.4 Three-Dimensional Static Strength
Prediction Program Model ................... 35-4
35.5 Discussion of Similarities and Differences ........ 35-5
35.6

Gary Mirka
Gwanseob Shin
North Carolina State University

A Hybrid Assessment Tool .................... 35-6

35.7 Additional Low Back Risk Assessment

Tool Needs . .............................. 35-7

35.1 Introduction

Over the last three decades, several low back injury risk assessment tools have been developed to provide
ergonomics practitioners the ability to evaluate the relative risk posed by manual materials handling
(MMH) tasks. The Work Practices Guide for Manual Lifting (NIOSH, 1981) and the Revised NIOSH
Lifting Equation (Waters et al., 1993, 1994) are two well-established methods developed by the National
Institute for Occupational Safety and Health (NIOSH). The Lumbar Motion Monitor (LMM) risk assess-
ment model (Marras et al., 1993) and the Three-Dimensional Static Strength Prediction Program TM
(3DSSPP) were developed by researchers at The Ohio State University and the University of Michigan,
respectively. The goals of this paper are to compare and contrast these existing assessment models,
develop the motivation for a hybrid modeling technique and identify gaps in our current low back
injury risk assessment techniques for other high-risk activities.

35.2 NIOSH Lifting Equations

In 1981, the NIOSH published the Work Practices Guide for Manual Lifting (NIOSH, 1981) to provide
industry with an assessment tool aimed at identifying jobs that carry an increased risk of low back injury.
The general approach was to use basic data from the biomechanical, epidemiological, psychophysical, and
physiological literature to create an assessment tool to quantify risk during MMH tasks. The mechanics
of the tool require that the analyst gather important task-related data that describes the lifting task (i.e.,
the vertical location of the load, the distance of the load away from the spine, the required frequency of
the lifting task and the vertical distance of travel of the load), and then use these data in a multiplicative
model that derives an action limit (AL) value and a maximum permissible limit (MPL) value using the
classic industrial hygiene approach. If the actual weight that the worker is asked to lift is below this AL

35-1