Week 9 Readings Flashcards
Outline the assumptions and limitations of the liberty mutual equations
Assumptions
- Estimated maximum acceptable load output applies to tasks performed in 8 hours in favourable ambient temperatures
Limitations
- Equations should be used for 2 handed tasks without trunk twisting or lateral bending
- Lifting, lowering, and carry equations do not account for box length or height
- Lift and lower equations apply to conditions where boxes or containers have handles
What did Potvin et al. add to the assessment of MMH with the LM-MMH equations. How were the equations validated?
- Increased empirical data
- More recent data
- Wider range of reaches for lifting and lowering
- Full lifting and lowering vertical ranges
Validation:
1. Comparison with liberty mutual tables
2. Comparison with empirical data
What are the assumptions behind the LiFFT analysis?
- Musculoskeletal disorders result from fatigue failure process in the tissues
- Peak load moment is used to estimate compression load on the spine
- Compression load is estimated by comparing peak load moment values to average compressive strength of a mixed male/female sample
How was the LiFFT analysis validated?
LiFFT was validated using two databases containing information on peak load moment (PLM), number of lifts, and low back outcomes
- Liberty Mutual Manual Materials Handling (LMM) Database
- Automotive Manufacturer Database
