1. Developing a Method for the Design and Evaluation of Manual Lifting Tasks

2. National Institute for Occupational Safety and Health (NIOSH)
1981
committee met to recommend criteria for defining lifting capacity
evaluate lifting demands

3. NIOSH Lifting Equation
Criteria:
1. Biomechanical
- loading of the spine
2. Physiological
- energy expenditure
3. Psychophysical
- capacity to lift

4. NIOSH Lifting Equation
Goal:
Identify ergonomic solutions for reducing physical stresses
1991 revised version

5. Activity
Keeping in mind the goal (and criteria) of the NIOSH committee
Identify features/factors of a lifting task that contribute the most to the hazard of low back injuries

6. Revised NIOSH Lifting Equation (1991)
Lifting equation for calculating the Recommended Weight Limit (RWL)
represents a load nearly all healthy workers could perform (up to 8 hrs.) w/o  risk of developing lifting-related LBP

7. RWL RWL = LC x HM x VM x DM x AM x FM x CM LC = 51 lbs.
HM = horizontal (initial horizontal position)
VM = vertical (initial vertical position)
DM = distance (total vertical distance moved)
AM = asymmetric
FM = frequency
CM = coupling

8. RWL RWL = LC x HM x VM x DM x AM x FM x CM LC = 51 lbs. HM = 10/H
VM = 1 - (.0075|V - 30|)
DM = (1.8/D)
AM = 1 - (.0032 * A)
FM = Table
CM = Table

9. Lifting Index (LI)
Ratio or comparison between actual weight lifted (L) and RWL
LI = Load Weight / RWL
Relative index of physical stress