CIH Ergonomics and Biomechanics 3

Question 1

Which segment of the spine bears the greatest compressive load during forward bending with a load in the hands?

Accepted Answer

Lumbar L4-L5

Answer

The L4-L5 disc is subjected to the highest compressive forces during lumbar flexion with external loads.

Question 2

The RULA (Rapid Upper Limb Assessment) tool was primarily designed to evaluate risk in which type of work?

Accepted Answer

Sedentary tasks with sustained upper limb postures

Answer

RULA assesses upper limb posture, force, and repetition in sedentary tasks such as office and assembly work.

Question 3

What is the primary biomechanical disadvantage of a wide grip span (>2 inches) when using a power hand tool?

Accepted Answer

Increases grip strength requirement by raising internal joint forces

Answer

A grip span exceeding the optimal 1.75–2 inches requires greater muscle force, increasing tendon and joint loading.

Question 4

During a job demands analysis, a task requires exerting 15 lbs of push force with both hands. This best represents which ergonomic risk factor?

Accepted Answer

Forceful exertion

Answer

Applying 15 lbs of push force constitutes forceful exertion, a primary ergonomic risk factor for upper extremity MSDs.

Question 5

Which workplace intervention is considered the most effective (highest hierarchy) for reducing MSD risk?

Accepted Answer

Engineering controls that eliminate the hazardous task

Answer

Engineering controls rank highest in the hierarchy of controls, addressing hazards at the source rather than managing exposure.

CIH - Certified Industrial Hygienist Exam Practice Test