3550 Final Flashcards
What is anthropometry derived from?
Greek words “Anthropos”, meaning man and “Metron”, meaning to measure
What is anthropometry?
AKA human measurement
Concerned with the physical sizes and shapes of humans
Measurement of size, mass, shape, and inertial properties of the human body for occupational, recreational, and design purposes.
Anthropometry and ergonomics
User-centered design
- Achieve best match between product, user and task
Also want to match to the environment
What defines anthropometric success?
- Efficiency (measured by productivity, task performance, etc.)
- Ease of use
- Comfort
- Health and Safety
- Quality of working life
User-Centered Design (4)
- Empirical
- Iterative
- Participative
- Non-Procrustean
Empirical
- Capable of being verified or disproved by observation or experiment
- Can we quantify whether or not it is usable?
Part of User-Centered Design
Iterative
Cyclical process
1. Research of empirical studies
2. Design phase
3. Evaluate design empirically
Multiple cycles that you should be going through. This is specific to product design but can also be applied into individual ergonomic assessment. In step 1 is where you’d get most anthropometric values from (use tables more so than doing it manually).
- Once we have determined best way to design things go through physical design phase. Once product has been designed then we evaluate the design by having actual people use it. Not released to the masses immediately, have test groups to try product on.
Part of User-Centered Design
Participative
-End-user should be included in design process
Part of User-Centered Design
Non-Procrustean
-Deals with people as they are rather than as they might be - FJP!!!
Trying to fit product to person
Part of User-Centered Design
Benefits of User-Centered Design
- Accounts for human diversity
- Accounts for the task
- Systems oriented
- Pragmatic – recognizes there may be limits to what is reasonably practical. Seeks to reach the best possible outcome within the constraints imposed by these limits
Need to design best product/space based on constraints you are given
2 Types of Anthropometry
Physical or static
Functional or dynamic
Physical or Static Anthropometry
o Obtained when body is in a fixed position
o Consists of skeletal dimensions between landmarks or of contour dimensions
Functional or Dynamic Anthropometry
o Obtained when the body is engaged in physical activity
o The “functional” dimension reflects a composite of different body segments functioning together.
usually need static measurements and then apply them to certain dynamic situations
Static and Dynamic Dimensions
- Physical analysis suggests that only the measurements of the body segment lengths in fixed positions need to be considered in the design of workplaces.
- Functional analysis implies that the acceptability of a workplace design has to be evaluated with respect to the needed movements of the body from one position to another.
- Seldom it’s all or none often do a mix of both.
Anthropometric Data
Results obtained from these methods are statistical data that can be applied in the design of products, clothing, occupational, and recreational environments.
Anthropometric Data Assumptions
- We assume the population and parameter / measurement of interest follows a normal distribution
- 5th and 95th percentile
- We assume the measurement we are taking follows a normal distribution and for this to be accurate need to take these measurements with a large population.
- Product design parameters is often set from 5th percentile female to 95th percentile male. This is done to account for the vast majority of the population.
Why use anthropometry?
Natural postures and movements are essential for life and efficient work. Therefore, our surroundings should be suited to those in it
To design the best product…
o Must know your user population
o The criteria for deciding on a population are functional and depend on the problem at hand
What might cheaper products have
Some products that are cheaper might only be set to 50th percentile and have less adjustability.
There is enormous variability in body due to:
- Age
- Gender
- Ethnic diversity
- Natural variability
What are the 5 design principles?
- Custom-fit each individual
- Have several fixed sizes
- Make it adjustable
- Design for the extremes
- Select people whose bodies fit the existing design
Lumping 2 and 3 together is one of the most practical and best practices to take
Custom-fit each individual
Best approach in terms of fit/comfort/safety, but laborious and expensive
- Some places have multiple employees at a station (shift rotation, or hourly). Would need to then account for each individuals. Best approach would be to make sure that everyone would fit and could work at that station
Have several fixed sizes
Reasonable solution, but all sizes must be available and “between-sized” individuals may not be accommodated
Make it adjustable
Approach that usually provide the best fit to all people
Design for the extremes
Appropriate solution when safety is the greatest concern
Select people whose bodies fit the existing design
Least appropriate solution. Should be avoided as much as possible (FPJ!!!)
All other options need to be explored before this. Want to avoid this as much as possible. Certain professions have criteria that needs to be met and ppl need to fit the existing parameters.
Designing Adjustable Ranges Typical
Standard practice is to design for the 5th-95th range for relevant characteristics of specific user group
- Marketability, safety and flexibility are important issues involved
Issue with designing for 5-95
Bittner (1974) – looked at 5th and 95th percentiles on 13 dimensions for a chair
Would have excluded 52% of population instead of 10% implied by percentiles
- body measurements are not perfectly correlated
- Just need to be above or below on one dimension
- The more you have the greater the chance someone is excluded
Design for adjustable ranges process
Mitigates the likelihood of eliminating sections of the user population due to design limitations.
- Adjustability vs. Fixed Sizes
Harnesses, Helmets, bikes, office and car seats, seatbelts
- First step is to determine the critical dimensions, then design mechanism of adjustability with emphasis on ease of operation
- Instructions and/or training program on how to and importance of proper adjustment
Designing for Extremes Process
- There may be a limiting factor in the design that will dictate usability
- Design for maximum value of design features OR design for minimum value of design features
- These are often very much about safety for the “outliers”
- Traditionally, extremes have been addressed by designing for
- 5th percentile female (smallest)
- 95th percentile male (largest)
Designing for Extremes Safety
- When the sole purpose of something is for safety then you need to go to 1st percentile female or 99th male
- On final will be explicitly with what measurements he wants us to use. If told designing a general product for general purposed default to 5-95th. If it’s for safety default to the 1st to 99th percentile in cases like that.
Design for minimum dimension
Used to accommodate largest individuals
For example
- width of a grocery aisle
- width of a chair
- clearance dimensions
- escape hatch in airplane
- When we use a minimum set we account for the largest individuals. If we set the width of a grocery aisle to accommodate the largest person in a society then those who are smaller can fit. Minimum dimensions of aisles needs to be x.
- Smallest it can be is x will accommodate for larger people
Design for maximum dimension
Used to accommodate smallest individuals
For example
-a fire alarm
- bus seat height and depth
- reach dimensions
Anthropometric planes
- Frontal (divides into front and back)
- Sagittal (divides into left and right)
- Transverse (divides body into top and bottom)
Anthropometric Measurements
Height
- From lowest point (often floor) to highest point on individual
Breadth (Width)
- Widest point (on individual) – measure from left to right
Depth
- Anterior to posterior
Distance
- Measuring from one reference point to another reference point
Curvature
- Measuring from one point to another but factoring in the curvature of the object/individual. Not a straight-line measurement. Factoring in curves!
Circumference
- Of a body segment
Reach
Seated measurements
◦ The seat and floor need to be parallel and horizontal.
◦ The knees need to be bent at a 90° angle.
◦ Thighs need to be placed in a horizontal position and the lower legs need to be placed in a vertical position.
◦ The feet have to be horizontally flat on the ground.
Want chair/stool that is adjustable so you can get into proper position.
- Want to hit this criteria so you are standardizing where measurements are taken from so measurements that are taken apply to all diff circumstances/objects
Stature Measurements
Need to be in 1 of 4 positions
Regardless of the position in which the subject is measured, consistency of this position within the sample group for which measurements are taken is critical.
◦ Standing upright naturally
◦ Standing upright erect
◦ Standing against a wall
◦ Lying supine
Which one you use depends on the context
Standing upright naturally
Slumping effect is included in measurements.
Standing upright erect
Measurements can have a 2 cm difference when the subject standing either stretches to a fully erect position or just stands upright naturally.
Standing against a wall with shoulder blades, buttocks, and back of the head touching the wall
Extending a book or straight edge from the top of the head to the wall, making a mark on the wall, and then measuring the distance to the floor helps ensure the subject is fully upright and provides a mechanism for consistency between subjects.
Lying supine
◦ Provides the tallest measurement as gravity will not compress the spine.
◦ Taking measurements in the morning also provides the tallest measurement.
Lying supine
◦ Provides the tallest measurement as gravity will not compress the spine.
◦ Taking measurements in the morning also provides the tallest measurement
