Ergonomic Design & Intervention Strategies Flashcards

When evaluating a push/pull task using the Liberty Mutual Psychophysical Tables, the primary variable affecting acceptable force limits is:

Answer: Task frequency, distance, and height of force application

The Liberty Mutual tables account for frequency of exertion, distance traveled, and the height at which force is applied to determine acceptable limits.

A manufacturer switches from a two-handed manual torque wrench to a pneumatic torque tool that auto-stops at the target value. This addresses which ergonomic risk factor?

Answer: High grip force combined with repetitive wrist deviation

Powered torque tools eliminate the high grip force and repetitive wrist motion needed to manually torque fasteners, reducing MSD risk.

Which seating characteristic most directly reduces ischial tuberosity pressure during prolonged sitting?

Answer: Seat pan cushion with appropriate density and contour

A properly contoured and density-appropriate cushion distributes pressure away from the ischial tuberosities, reducing localized tissue loading.

In an ergonomic intervention for a nurse performing patient transfers, a ceiling-mounted lift system is installed. This represents which level of the hierarchy of controls?

Answer: Engineering control

Installing a mechanical lift system modifies the physical work environment to remove manual lifting demands, classifying it as an engineering control.

What is the recommended maximum vertical lift zone according to the revised NIOSH Lifting Equation for optimal load constant application?

Answer: 75 cm (knuckle height) as the origin point for least multiplier penalty

The NIOSH equation origin point at knuckle height (~75 cm) incurs no vertical multiplier penalty, representing the optimal lift height.

An ergonomics program evaluation should use which metric to demonstrate effectiveness over a 12-month post-intervention period?

Answer: Reduction in MSD incidence rate and days away from work

Outcome metrics such as MSD incidence rates and lost workday reductions directly measure whether interventions improved worker health.

Which characteristic distinguishes a cumulative trauma disorder (CTD) from an acute occupational injury in ergonomics practice?

Answer: CTDs develop gradually from repeated low-level exposures over time rather than a single event

Cumulative trauma disorders result from repeated exposure to ergonomic stressors over weeks, months, or years, unlike acute injuries caused by a single event.