AEP Core Knowledge Areas 3 — Questions and Answers
Question 1: When calculating the NIOSH Recommended Weight Limit (RWL), the Load Constant (LC) of 51 lbs represents:
- The maximum allowable weight for any manual lifting task
- The weight that nearly all healthy adults can lift under ideal conditions without spinal injury risk (Correct answer)
- The average body weight used to normalize metabolic load
- The weight threshold above which mechanical assistance is always required by OSHA
Correct answer: The weight that nearly all healthy adults can lift under ideal conditions without spinal injury risk
The 51-lb LC is the maximum recommended load under ideal lifting conditions (close, waist-height, symmetric, infrequent lift), derived to protect most healthy workers.
Question 2: An ergonomist uses an accelerometer to measure hand-arm vibration. The result is expressed as an 8-hour energy-equivalent frequency-weighted acceleration (A(8)). What standard provides the US exposure action value and limit value guidance?
- ACGIH TLV for hand-arm vibration
- ANSI S2.70 and ISO 5349-1 (Correct answer)
- OSHA 29 CFR 1910.95 noise standard
- NIOSH REL for whole-body vibration
Correct answer: ANSI S2.70 and ISO 5349-1
ISO 5349-1 defines the method for measuring and evaluating hand-arm vibration exposure, including the frequency-weighted A(8) metric widely referenced in US guidelines.
Question 3: A call center ergonomist recommends a headset instead of a handset for customer service representatives. Which ergonomic risk factor does this primarily address?
- Contact stress on the palm from gripping the handset
- Static shoulder elevation and lateral neck flexion from cradling the handset (Correct answer)
- Repetitive fine-motor finger movements required to dial
- Whole-body vibration transmitted through the desk surface
Correct answer: Static shoulder elevation and lateral neck flexion from cradling the handset
Cradling a handset between the ear and shoulder forces prolonged lateral neck flexion and shoulder elevation, which headsets eliminate by freeing both hands.
Question 4: In office ergonomics, what is the recommended distance between the monitor screen and the user's eyes for standard office work?
- 10–15 inches (25–38 cm)
- 18–30 inches (46–76 cm) (Correct answer)
- 32–40 inches (81–102 cm)
- 12–18 inches (30–46 cm)
Correct answer: 18–30 inches (46–76 cm)
A viewing distance of 18–30 inches (approximately arm's length) is recommended to reduce eye strain and support a neutral head posture.
Question 5: Which of the following BEST describes the concept of 'coupling' in the context of manual materials handling?
- The mechanical connection between a power tool and its vibrating component
- The quality of the grip between the worker's hands and the object being handled (Correct answer)
- The linking of sequential job tasks to calculate cumulative strain
- The synchronization of two workers performing a team lift
Correct answer: The quality of the grip between the worker's hands and the object being handled
In the NIOSH equation, coupling refers to how well a worker can grip the load; good coupling (handles, cut-outs) reduces required grip force and spinal loading.
Question 6: A worker reports tingling and numbness in the thumb, index, and middle fingers, worsening at night. Which musculoskeletal disorder does this pattern MOST suggest?
- Cubital tunnel syndrome (ulnar nerve entrapment at the elbow)
- Carpal tunnel syndrome (median nerve compression at the wrist) (Correct answer)
- Thoracic outlet syndrome (brachial plexus compression at the shoulder)
- De Quervain's tenosynovitis (first dorsal compartment tendon inflammation)
Correct answer: Carpal tunnel syndrome (median nerve compression at the wrist)
Carpal tunnel syndrome causes median nerve compression, producing paresthesia in the thumb, index, middle, and radial half of the ring finger, often worse at night.
Question 7: What does the Strain Index (SI) tool primarily evaluate?
- Spinal compression forces during asymmetric lifts
- Risk of distal upper-extremity disorders from job task exposures (Correct answer)
- Whole-body metabolic strain during strenuous manual labor
- Lower-extremity joint loading during prolonged standing tasks
Correct answer: Risk of distal upper-extremity disorders from job task exposures
The Strain Index scores six task variables (intensity of exertion, duration, frequency, posture, speed, task duration/day) to estimate risk of distal upper-extremity disorders.
AEP Core Knowledge Areas 3
When calculating the NIOSH Recommended Weight Limit (RWL), the Load Constant (LC) of 51 lbs represents: