design tech: A 1.1 ergonomics

What is ergonomics?

Designing products around human abilities, needs and limitations.

What is the main aim of ergonomics?

To improve safety, comfort, efficiency and usability.

What is anthropometry?

The measurement of human body dimensions.

What is static anthropometry?

Body measurements taken while the body is stationary.

What is dynamic anthropometry?

Body measurements taken while the body is moving.

Give an example of static anthropometry.

Standing height, sitting height or shoulder width.

Give an example of dynamic anthropometry.

Maximum reach or range of arm movement.

What is a percentile?

A value showing how a measurement compares within a population.

What does the 5th percentile represent?

A relatively small user; about 5% are smaller.

What does the 50th percentile represent?

The median; about half are smaller and half larger.

What does the 95th percentile represent?

A relatively large user; about 95% are smaller.

When would you design for the 5th percentile?

When smaller users need to reach or operate something.

When would you design for the 95th percentile?

When larger users need to fit or have enough clearance.

Why is adjustability useful?

It allows products to accommodate a wider range of users.

Give an example of an adjustable product.

An office chair with adjustable height and back support.

What is an ergonomic envelope?

The space within which a user can comfortably interact with a product.

What is reach?

The distance a person can extend to interact with something.

What is comfortable reach?

A reach distance requiring little or no excessive stretching.

What is maximum reach?

The furthest distance a person can reach.

What is clearance?

Space provided for a person's body to fit or move safely.

Why is clearance important?

It prevents restriction and allows safe movement.

What is biomechanics?

The study of forces and movement in the human body.

How does biomechanics relate to ergonomics?

It helps designers reduce physical stress and injury risk.

What is posture?

The position or alignment of the body.

What is neutral posture?

A natural, balanced position that reduces physical strain.

Why is good posture important?

It reduces fatigue, discomfort and risk of injury.

What is force in ergonomics?

The physical effort required to operate or interact with a product.

Why should required force be minimised?

To reduce fatigue, discomfort and injury risk.

What is torque?

The rotational effect produced by a force.

What is the formula for torque?

Torque = force × perpendicular distance from the pivot.

How can a longer handle reduce required effort?

It increases the distance from the pivot, increasing torque.

What is fatigue?

Reduced physical capacity caused by sustained or repeated activity.

What ergonomic factors can increase fatigue?

Repetition, excessive force, awkward posture and long duration.

What is repetitive strain injury (RSI)?

Injury caused by repeated movements or prolonged positions.

Give an example of an RSI.

Carpal tunnel syndrome, tendinitis or tennis elbow.

How can ergonomic design reduce RSI?

Reduce repetition, force and awkward postures.

Why is grip design important?

It affects comfort, control, force and safety.

What factors affect grip design?

Hand size, diameter, shape, texture, material and required force.

What happens if a handle is too small?

Pressure on the hand can increase, causing discomfort.

What happens if a handle is too large?

It can become difficult to grip securely.

What is contact stress?

Stress caused when force is concentrated over a small body area.

How can contact stress be reduced?

Increase contact area using padding or wider surfaces.

What is the pressure formula?

Pressure = force ÷ area.

How does increasing contact area affect pressure?

Increasing area reduces pressure.

Why can vibration be an ergonomic concern?

Long-term vibration can cause discomfort, fatigue and injury.

How can vibration be reduced?

Use damping materials, rubber grips or suspension.

Why should designers consider temperature?

Extreme temperatures can cause discomfort or affect product use.

What visual factors affect ergonomics?

Lighting, contrast, glare, font size, colour and display position.

What is inclusive design?

Design that considers a broad range of users and abilities.

What is universal design?

Design intended to be usable by the widest range of people.

What is the difference between ergonomics and anthropometry?

Anthropometry measures people; ergonomics applies this to design.

What is the difference between ergonomics and biomechanics?

Ergonomics studies human-product interaction; biomechanics studies forces and movement.

Why do designers use anthropometric data?

To choose suitable product dimensions for users.

What body measurements could affect chair design?

Hip width, leg height, thigh length and sitting height.

What anthropometric measurement affects seat width?

Hip width.

What measurement affects seat height?

Popliteal/leg height.

What measurement affects seat depth?

Buttock-to-popliteal or thigh length.

What is user testing?

Testing a product with real users to evaluate its performance.

Why is user testing important?

It identifies comfort, usability and ergonomic problems.

What is observation in ergonomic testing?

Watching users interact with a product to identify problems.

What is task analysis?

Breaking a task into individual actions to identify design requirements.

Why are prototypes useful for ergonomics?

They allow designers to test dimensions, comfort and usability.

What is one purpose of ergonomic evaluation?

To identify weaknesses and improve the product.

What user characteristics should designers consider?

Age, size, strength, ability, experience and physical capability.

What product characteristics affect ergonomics?

Size, shape, weight, materials, controls, grip and adjustability.

What environmental factors affect ergonomics?

Lighting, temperature, noise, vibration and available space.

What task factors affect ergonomics?

Duration, frequency, repetition, force and precision.

What is an ergonomic design process?

Identify users → collect data → design → prototype → test → evaluate → improve.

Why should designers consider a range of users?

People vary greatly in body size, strength and ability.

Why can't designers always design for the 50th percentile?

The average user may not accommodate smaller or larger users.

When should designers use the 5th percentile for reach?

When they need most users, including small users, to reach it.

When should designers use the 95th percentile for clearance?

When they need larger users to fit comfortably.

What is a major advantage of adjustable design?

One product can accommodate users with different body dimensions.

What is the key principle of ergonomics?

Design the product around the human, not the human around the product.