CHST Ergonomics and Musculoskeletal Disorder (MSD) Prevention 5

Question 1

What is the recommended handle diameter for a power-grip hand tool to reduce hand strain?

Accepted Answer

About 1.25 to 2 inches (30 to 50 mm)

Answer

Handles of roughly 30-50 mm let the hand wrap fully around them, giving the most grip strength with the least effort.

Question 2

Why is a pinch grip riskier than a power grip for repetitive tasks?

Accepted Answer

A pinch grip produces much less force, so the tendons work harder for the same load

Answer

A pinch grip produces only a fraction of power-grip strength, which raises tendon load for the same task.

Question 3

A tile setter who kneels for long periods is at risk of which disorder?

Accepted Answer

Prepatellar bursitis

Answer

Constant pressure on the front of the knee irritates the prepatellar bursa, causing so-called housemaid's knee.

Question 4

For an installer drilling anchors into a concrete ceiling, which control best reduces shoulder strain?

Accepted Answer

An inverted drill stand that lets the worker drill while standing with arms below shoulder height

Answer

Drill stands take the weight and keep the arms out of sustained overhead postures, the main cause of shoulder strain.

Question 5

When moving a loaded material cart across a job site, which practice generally lowers MSD risk?

Accepted Answer

Pushing rather than pulling, with large-diameter wheels on a smooth path

Answer

Pushing lets workers use body weight with better posture, and large wheels on smooth surfaces cut the starting and rolling force.

CHST - Construction Health and Safety Technician Practice Test