CIH Ergonomics and Biomechanics 2 — Questions and Answers
Question 1: Which of the following best describes the 'neutral posture' in ergonomics?
- Joints held at their mid-range positions minimizing tissue stress (Correct answer)
- Spine fully extended with shoulders retracted
- Wrists flexed at 45 degrees for power grip
- Elbows locked at full extension during lifting
Correct answer: Joints held at their mid-range positions minimizing tissue stress
Neutral posture keeps joints near mid-range, reducing loading on muscles, tendons, and ligaments.
Question 2: The NIOSH Lifting Equation Recommended Weight Limit (RWL) is calculated from the load constant of 51 lbs multiplied by how many task-specific multipliers?
- 4
- 5
- 6 (Correct answer)
- 7
Correct answer: 6
The RWL uses six multipliers: horizontal, vertical, distance, asymmetry, frequency, and coupling.
Question 3: A worker reports numbness and tingling in the thumb, index, and middle fingers. Which nerve is most likely compressed?
- Ulnar nerve
- Radial nerve
- Median nerve (Correct answer)
- Musculocutaneous nerve
Correct answer: Median nerve
The median nerve passes through the carpal tunnel and innervates the thumb, index, and middle fingers.
Question 4: What does the term 'coupling' refer to in the context of the NIOSH Lifting Equation?
- Distance between the worker and the load
- Quality of the hand-to-object interface (Correct answer)
- Symmetry of the lift relative to body midline
- Frequency of repetitive lifting tasks
Correct answer: Quality of the hand-to-object interface
Coupling describes how well a worker can grip the load, ranging from good (handles) to poor (no grip points).
Question 5: Which anthropometric measurement is most critical when designing a seated workstation keyboard height?
- Stature
- Popliteal height
- Elbow height while seated (Correct answer)
- Shoulder breadth
Correct answer: Elbow height while seated
Seated elbow height determines the optimal keyboard height to maintain neutral wrist and shoulder posture.
Question 6: Repetitive pinch grip tasks are especially associated with increased risk of which musculoskeletal disorder?
- Lateral epicondylitis
- De Quervain's tenosynovitis (Correct answer)
- Thoracic outlet syndrome
- Radial tunnel syndrome
Correct answer: De Quervain's tenosynovitis
De Quervain's tenosynovitis affects the tendons of the thumb and is aggravated by repeated pinching and twisting.
Question 7: In whole-body vibration exposure assessment, which ISO standard is most commonly referenced?
- ISO 9241
- ISO 2631 (Correct answer)
- ISO 11228
- ISO 10068
Correct answer: ISO 2631
ISO 2631 provides guidance for measuring and evaluating whole-body vibration exposure and its health effects.
CIH Ergonomics and Biomechanics 2
Which of the following best describes the 'neutral posture' in ergonomics?