CPE Anthropometry & Physical Dimensions in Ergonomics 1 — Questions and Answers
Question 1: When designing workstations to accommodate the widest practical range of users, which percentile range is the ergonomic design standard?
- 1st to 99th percentile
- 5th to 95th percentile (Correct answer)
- 10th to 90th percentile
- 25th to 75th percentile
Correct answer: 5th to 95th percentile
The 5th to 95th percentile range is the accepted ergonomic standard, accommodating 90% of the target population while balancing cost and design feasibility.
Question 2: Which anthropometric measurement is most critical for determining appropriate seated workstation surface height?
- Standing stature
- Popliteal height (Correct answer)
- Sitting eye height
- Shoulder height seated
Correct answer: Popliteal height
Popliteal height (floor to the underside of the thigh just behind the knee) directly determines proper seat height, which in turn drives workstation surface height.
Question 3: When designing a fixed overhead clearance (e.g., a doorway or ceiling-mounted obstacle), ergonomic guidelines recommend designing for which user group?
- Average user (50th percentile combined)
- 5th percentile female stature
- 95th percentile male stature (Correct answer)
- Mean of male and female 50th percentiles
Correct answer: 95th percentile male stature
Clearance dimensions must accommodate the largest user; if the tallest person fits safely, everyone in the population will as well.
Question 4: Functional reach differs from structural (static) reach in that functional reach:
- Measures arm length with the elbow locked and shoulder fixed
- Includes trunk rotation and shoulder movement during the reach (Correct answer)
- Is always shorter than structural reach by a fixed percentage
- Is measured with both arms extended overhead simultaneously
Correct answer: Includes trunk rotation and shoulder movement during the reach
Functional reach accounts for natural body movement during task performance — including trunk rotation and shoulder protraction — making it more representative of actual workplace reach capability.
Question 5: The 'secular trend' in anthropometry refers to which phenomenon?
- Seasonal variation in body dimensions due to temperature
- The gradual increase in average human body size across successive generations (Correct answer)
- Measurement variability caused by time-of-day effects on stature
- Stature reduction due to spinal compression with aging
Correct answer: The gradual increase in average human body size across successive generations
Secular trend describes the documented generational increase in average stature and body mass, requiring ergonomists to use updated anthropometric databases for contemporary design.
Question 6: The ANSUR II database is valued by ergonomists primarily because it provides:
- ISO-standardized civilian workplace anthropometric norms
- Comprehensive US Army anthropometric data with over 100 measurements per participant (Correct answer)
- WHO pediatric growth and developmental measurement standards
- OSHA-mandated minimum anthropometric accommodation thresholds
Correct answer: Comprehensive US Army anthropometric data with over 100 measurements per participant
ANSUR II (2012) surveyed approximately 6,000 US Army personnel with over 100 body measurements each, making it one of the most comprehensive North American anthropometric datasets available for equipment and workstation design.
Question 7: When a single fixed workstation dimension cannot accommodate both a 5th percentile female and a 95th percentile male user, the preferred ergonomic design approach is:
- Design for the 50th percentile average user
- Design for adjustability across the required range (Correct answer)
- Design for the smallest user only to minimize reach distances
- Design for the largest user only to maximize clearance
Correct answer: Design for adjustability across the required range
When the population span is too great for a single fixed dimension to serve all users, adjustable workstations allow the same design to accommodate the full range of anthropometric variation.
CPE Anthropometry & Physical Dimensions in Ergonomics 1
When designing workstations to accommodate the widest practical range of users, which percentile range is the ergonomic design standard?