CIEE Workstation Design & Optimization 4 — Questions and Answers
Question 1: An ergonomist notices a quality inspector leaning forward 30° from the vertical for most of the shift. Which workstation modification is most likely to correct this?
- Adding a padded armrest to the chair
- Raising the work surface or bringing inspection fixtures closer to the worker (Correct answer)
- Prescribing lumbar support cushions
- Providing a kneeling chair
Correct answer: Raising the work surface or bringing inspection fixtures closer to the worker
Forward trunk lean is typically caused by work that is too far away or too low; bringing the work to the worker eliminates the need for postural compensation.
Question 2: Which NIOSH lifting equation variable accounts for the horizontal distance of the load from the worker's spine at the origin of the lift?
- Vertical location (V)
- Horizontal location (H) (Correct answer)
- Asymmetry angle (A)
- Coupling multiplier (CM)
Correct answer: Horizontal location (H)
The horizontal location multiplier (HM = 25/H) penalizes lifts where the load is far from the body, as this increases the moment arm on the lumbar spine.
Question 3: A workstation redesign eliminated a bend-and-reach task by installing a powered turntable that brings parts to the worker. This is an example of which ergonomic principle?
- Administrative control through job rotation
- Engineering control—bringing the work to the worker (Correct answer)
- PPE provision for musculoskeletal protection
- Work practice control through training
Correct answer: Engineering control—bringing the work to the worker
Installing equipment that delivers materials to the worker without requiring awkward posture is a classic engineering control, highest in the hierarchy.
Question 4: When evaluating wrist posture at a keyboard, which combination of deviations is associated with the highest risk of carpal tunnel syndrome?
- Flexion combined with ulnar deviation
- Neutral with slight radial deviation
- Extension combined with ulnar deviation (Correct answer)
- Flexion combined with radial deviation
Correct answer: Extension combined with ulnar deviation
Extension combined with ulnar deviation maximally narrows the carpal tunnel and increases median nerve pressure, the highest-risk combination.
Question 5: Which seating parameter most directly affects popliteal pressure and lower-leg circulation in a sedentary worker?
- Backrest height
- Seat pan depth (Correct answer)
- Armrest height
- Seat width
Correct answer: Seat pan depth
Excessive seat pan depth causes the front edge to press against the popliteal area, compressing the popliteal vessels and nerves behind the knee.
Question 6: A worker who performs pipetting for 6 hours daily reports shoulder and forearm fatigue. Which workstation change should be evaluated first?
- Scheduling mandatory hourly breaks
- Adjusting bench height so the pipette is used at elbow height (Correct answer)
- Switching to a lighter-weight pipette model
- Rotating the worker to a different task every 2 hours
Correct answer: Adjusting bench height so the pipette is used at elbow height
Adjusting bench height to elbow level is an engineering control that eliminates sustained shoulder elevation and is evaluated before administrative solutions.
Question 7: In workstation design, 'visual angle' or the angle subtended by the display at the observer's eye is important because it determines:
- The risk of glare from overhead lighting
- The minimum character height needed for comfortable reading at a given viewing distance (Correct answer)
- The optimal monitor refresh rate
- The maximum allowable screen brightness in lux
Correct answer: The minimum character height needed for comfortable reading at a given viewing distance
Visual angle (typically ~0.2–0.3°) dictates minimum character size; insufficient visual angle causes users to lean forward, creating awkward neck and back postures.
CIEE Workstation Design & Optimization 4
An ergonomist notices a quality inspector leaning forward 30° from the vertical for most of the shift.
Which workstation modification is most likely to correct this?