Ergonomics and Musculoskeletal Disorder (MSD) Prevention Flashcards

In the revised NIOSH Lifting Equation, what is the load constant used to calculate the Recommended Weight Limit (RWL)?

Answer: 51 lb (23 kg)

The revised NIOSH equation starts from a 51 lb (23 kg) load constant, which the task multipliers then reduce.

A NIOSH Lifting Index (LI) of 2.4 for a block-laying task indicates what?

Answer: The task carries elevated risk of lifting-related low back pain for many workers

LI is load weight divided by RWL, and values above 1.0 show increased risk, rising as LI goes up.

Under the NIOSH Lifting Equation, what happens to the Horizontal Multiplier as a load is held farther from the body?

Answer: It decreases, lowering the RWL

HM = 10/H (inches), so a larger horizontal distance gives a smaller multiplier and a lower recommended weight.

What vertical hand height at the start of a lift does the NIOSH equation treat as optimal (multiplier of 1.0)?

Answer: About 30 inches (75 cm) above the floor

The Vertical Multiplier equals 1.0 at roughly knuckle height of 30 in (75 cm) and drops above or below that.

Which change would most improve the RWL for a laborer who twists 90 degrees to set pavers on a pallet?

Answer: Rearranging the layout so the worker faces the pallet without twisting

Getting rid of trunk twisting brings the Asymmetric Multiplier back toward 1.0 and raises the recommended weight limit.

Which ergonomic risk factor is the main concern when a worker ties rebar while bent at the waist for long periods?

Answer: Sustained awkward posture (trunk flexion)

Long periods of forward trunk flexion load the lumbar spine, and rebar tying is a classic example.

Which engineering control best reduces the stooped posture of rebar tying on slabs?

Answer: Long-handled or powered rebar tying tools

Extended-handle and battery-powered tiers let workers tie rebar while standing upright, removing the hazard at its source.