Ergonomics and Musculoskeletal Disorder (MSD) Prevention Flashcards

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

Answer: About 1.25 to 2 inches (30 to 50 mm)

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

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

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

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

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

Answer: Prepatellar bursitis

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

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

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

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

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

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

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

Which range is usually called the "power zone" for manual lifting?

Answer: Between mid-thigh and mid-chest, close to the body

Lifting between mid-thigh and mid-chest, close to the body, lets the strongest muscles work with the least spinal load.

Inflammation of the tendons on the thumb side of the wrist, often from repetitive gripping and twisting with hand tools, is called what?

Answer: De Quervain's tenosynovitis

De Quervain's tenosynovitis affects the abductor pollicis longus and extensor pollicis brevis tendons at the base of the thumb.