CES Human Factors & Biomechanics

Question 1

Which joint is most commonly stressed during prolonged overhead work tasks?

Accepted Answer

Shoulder (glenohumeral)

Answer

Overhead work requires sustained shoulder elevation, placing high mechanical load on the glenohumeral joint and surrounding rotator cuff muscles.

Question 2

What does the term 'neutral posture' refer to in ergonomics?

Accepted Answer

A position that minimizes mechanical stress on muscles and joints

Answer

Neutral posture describes body positions where joints are near their mid-range, minimizing mechanical stress and reducing injury risk.

Question 3

Which biomechanical principle explains why a longer lever arm increases the force needed by muscles?

Accepted Answer

Torque principle

Answer

Torque equals force multiplied by lever arm distance, so a longer lever arm requires greater muscle force to maintain equilibrium.

Question 4

What is the recommended maximum acceptable reach distance for frequent work tasks at seated workstations?

Accepted Answer

Within the primary work zone (elbow radius)

Answer

Frequent tasks should be performed within the primary work zone, approximately the elbow radius from the body, to minimize shoulder and trunk loading.

Question 5

Which cumulative trauma disorder is associated with repetitive pinch grip and lateral wrist deviation?

Accepted Answer

De Quervain's tenosynovitis

Answer

De Quervain's tenosynovitis involves inflammation of tendons controlling thumb movement and is aggravated by pinch grip combined with radial or ulnar deviation.

CES - Certified Ergonomic Specialist Practice Test

CES - Certified Ergonomic Specialist Practice Test

CES Human Factors & Biomechanics