IOP3704 Ergonomics and Human Factors Study Pack (UJ)

This study pack provides a structured, exam-focused guide to IOP3704 Ergonomics and Human Factors at the University of Johannesburg (UJ). It brings together the core theories, models, workplace applications, and exam-oriented revision points needed to understand how people interact with systems, equipment, environments, and tasks. The emphasis is on practical comprehension as well as academic precision, with examples aligned to South African organisational and work contexts.

1. Foundations of Ergonomics and Human Factors

1.1 What ergonomics and human factors mean

Ergonomics is the study of how work, tools, environments, and systems can be designed to match human abilities and limitations. Human factors is closely related, but it often places stronger emphasis on the psychological, cognitive, and organisational aspects of performance, safety, and well-being. In practice, the two fields overlap so extensively that many texts and institutions treat them as a single discipline. The central purpose is simple: to make systems fit people rather than forcing people to fit systems.

At university level, especially in an Industrial and Organisational Psychology context, ergonomics is not only about physical comfort. It is also about reducing error, improving productivity, preventing fatigue, supporting attention and decision-making, and improving quality of working life. A workplace can be mechanically efficient and still be ergonomically poor if workers are overstrained, distracted, poorly trained, or exposed to unsafe demands.

The field is especially relevant in modern workplaces where employees interact with computers, machinery, vehicles, interfaces, digital platforms, and complex processes. Even office work has strong ergonomic implications: sitting for long hours, using monitors placed at poor heights, repeated mouse movement, and awkward keyboard positions all contribute to musculoskeletal discomfort and lower performance.

1.2 Historical development and disciplinary roots

The modern field developed rapidly during the Second World War, when military systems became too complex and too dangerous to rely on equipment design alone. Aircrews, radar operators, and weapons personnel often made errors not because they were careless, but because the controls, displays, workload, and task sequences did not match human capability. This led to systematic study of people’s limitations in perception, attention, memory, and motor coordination.

After the war, the field expanded into industrial, transport, healthcare, and office environments. The growth of computing and automation later added new issues: information overload, interface design, alarm fatigue, and continuous screen-based work. Today, ergonomics is linked not only to injury prevention but also to organisational effectiveness, occupational health, and human-centred design.

A useful way to remember the historical progression is:

Wartime need for safer, more reliable human-machine systems
Industrial application to machinery, tools, and factory work
Office and computer expansion with repetitive work and static postures
Digital and cognitive ergonomics with software interfaces and complex information environments
System-wide human factors covering safety culture, workload, and organisational design

This development matters for exam purposes because it shows that ergonomics is not a narrow “chair and desk” topic. It is a broad multidisciplinary field connecting psychology, physiology, engineering, design, and management.

1.3 Core assumptions about the human being

Ergonomics rests on the idea that human beings have both strengths and limitations. People are adaptable, creative, and capable of handling complexity, but they are also vulnerable to fatigue, stress, distraction, and physical strain. A good system recognises both sides.

Important human characteristics include:

Limited strength and endurance: repeated heavy lifting or awkward force causes injury
Limited attention: sustained concentration declines over time
Limited working memory: people cannot hold too many items in mind at once
Variable performance: performance changes with sleep, health, stress, experience, and motivation
Sensory limitations: vision, hearing, and touch have thresholds and can be overloaded
Predictable bias and error tendencies: people use shortcuts and sometimes make systematic mistakes

These limitations are not evidence of failure. They are design constraints. If a system depends on perfect human behaviour, that system is poorly designed. Exam answers should repeatedly show that ergonomics seeks fit, safety, efficiency, and well-being by designing around human capability rather than idealised assumptions.

1.4 Key aims of ergonomics

The field usually pursues five interrelated aims:

Aim	Meaning	Example
Safety	Reduce risk of injury, illness, and accidents	Adjusting workstation height to prevent back strain
Efficiency	Improve output with less wasted effort	Reducing unnecessary movement in a packing process
Comfort	Reduce discomfort and fatigue	Providing adjustable chairs and screen positions
Quality	Reduce errors and improve consistency	Designing a control panel that prevents mistaken activation
Well-being	Support long-term health and satisfaction	Managing workload and breaks in call centres

The important exam point is that these goals are not separate. A safer system is often more comfortable, more efficient, and more reliable. However, there can also be trade-offs. For example, a highly automated system may reduce physical strain but increase boredom, reduced vigilance, or loss of skill if operators are under-engaged.

1.5 Ergonomics in South African work settings

In South African workplaces, ergonomics matters across mining, manufacturing, transport, retail, public services, higher education, and office-based administration. The realities of load shedding, equipment variation, mixed old and new infrastructure, and diverse worker populations make ergonomic design especially important. Many organisations also have to balance cost constraints with legal, ethical, and productivity demands.

Examples include:

A call centre in Johannesburg where repeated mouse clicking and poor seating create wrist and neck discomfort
A logistics warehouse where lifting techniques and shelf heights affect injury rates
A university computer lab where fixed desks and monitor heights do not suit all students
A healthcare setting where nurses experience high physical and cognitive workload
A truck transport environment where fatigue and scheduling interact with safety

The South African context is important because ergonomics cannot be treated as an abstract imported theory. It must work in real workplaces with diverse body sizes, languages, levels of training, and equipment quality.

2. Human Capabilities, Limitations, and Error

2.1 Physical characteristics and anthropometry

A major part of ergonomics is understanding anthropometry, the measurement of human body dimensions. Designers use body measurements such as height, sitting height, arm reach, leg length, hand breadth, and shoulder width to create equipment and workspaces that fit the population.

In practice, one design rarely fits everyone perfectly. A desk that suits a tall person may be uncomfortable for a shorter person, while a chair set for a shorter person may cause a taller person to hunch forward. Because of population variation, ergonomic design often uses percentiles rather than averages. Designing for the “average person” can leave many users poorly accommodated.

A common principle is to design adjustable systems where possible. This is especially important in shared environments such as:

Computer laboratories
Offices with hot-desking
Training rooms
Medical stations
Industrial control rooms

2.2 Using percentiles correctly

Percentiles help designers cover a target population. For example, a 5th percentile measurement means that only 5% of the population fall below that value and 95% fall above it. A 95th percentile means that 95% fall below that value and 5% exceed it.

Typical ergonomic interpretation:

Clearance dimensions should often accommodate larger users, often around the 95th percentile
Reach dimensions should often accommodate smaller users, often around the 5th percentile
Adjustable design is ideal because it reduces the need to choose one fixed percentile

This rule is not absolute. A seat height, for example, must balance reach to the floor with thigh clearance. Many exam questions expect a reasoning-based explanation rather than a memorised formula. The key is to justify why clearance and reach are designed differently.

2.3 Musculoskeletal strain and posture

Poor posture is not merely an aesthetic issue. It changes muscle loading, joint stress, circulation, and fatigue. Static postures are especially problematic because holding a position for long periods increases muscle tension even when the load is not heavy. Common risk patterns include:

Forward head posture while using a laptop
Rounded shoulders from prolonged keyboard work
Twisting and bending during lifting
Wrist deviation from poor keyboard and mouse placement
Prolonged sitting with inadequate lumbar support

Musculoskeletal discomfort often develops gradually. Workers may initially describe “just stiffness,” but over time this can progress to chronic pain or injury. Ergonomics therefore focuses on prevention, not only treatment.

2.4 Cognitive limitations and information processing

Human factors also studies the mind at work. People do not process all information equally. They select some cues, ignore others, make assumptions, and use mental shortcuts. Cognitive ergonomics examines:

Perception
Attention
Working memory
Decision-making
Situation awareness
Mental workload
Error generation

A person can have excellent technical knowledge and still make errors if the interface is confusing, the task is interrupted, or the workload is too high. For example, an administrator entering data into a complex system may mix up fields when pop-up messages interrupt their flow. The error is not simply “user incompetence”; it may be a design failure.

2.5 Human error: types and causes

Human error is often divided into three broad categories:

Error type	Description	Example
Slips	Correct intention, wrong action	Clicking the wrong button
Lapses	Memory failure or omission	Forgetting to save a document
Mistakes	Wrong intention or wrong decision	Choosing the wrong procedure because of poor diagnosis

These categories are useful because they show that not all errors are the same. Slips and lapses are often linked to distraction, fatigue, or poor interface design. Mistakes are often linked to incorrect understanding, faulty assumptions, or inadequate training.

A further distinction is between:

Active failures: immediate unsafe acts by front-line workers
Latent conditions: deeper organisational or design flaws that create the conditions for error

For exam answers, this distinction is powerful because it moves analysis beyond blaming the individual. A good human factors response asks what in the system made the error more likely.

2.6 Worked example: data entry in an office

Consider an employee entering supplier invoice details into a finance system. The employee is experienced, but the interface contains multiple similar drop-down menus, small fonts, and frequent alert pop-ups. By the end of the day the employee is tired and rushed because of a deadline.

Possible ergonomic issues include:

Screen layout that increases visual strain
Repetitive hand movement leading to wrist fatigue
Cognitive overload due to similar field names
Time pressure increasing slips and mistakes
Poor feedback from the system making it hard to detect errors

A human factors response would not simply tell the employee to “be more careful.” It would involve interface redesign, workload review, training, error-proofing, and perhaps scheduling changes.

3. Ergonomic Design Principles in Work Systems

3.1 The work system perspective

Ergonomics is best understood as a system discipline. A work system contains at least the following interacting components:

The person
The task
The tools and equipment
The physical environment
The organisational context

Each component affects the others. A well-trained worker may still perform badly in excessive heat, under poor lighting, or with defective tools. Similarly, excellent equipment may fail if the task sequence is badly designed or if the organisation creates time pressure and confusion.

The work system approach is powerful because it prevents simplistic explanations. Performance is not located in the person alone. It emerges from the interaction between people and their environments.

3.2 Designing the task

Task design concerns how work is structured. Important elements include:

Variety versus monotony
Work pace
Task significance
Autonomy
Complexity
Break frequency
Degree of repetition
Level of physical demand

A task that is too simple can cause boredom, reduced attention, and low motivation. A task that is too complex can overwhelm working memory and increase errors. Good ergonomic task design seeks a balanced challenge.

Practical principles of task design

Match task demands to human capacity
Reduce unnecessary repetition
Allow recovery time
Use job rotation where appropriate
Separate critical and noncritical tasks
Standardise sequences when safety depends on consistency
Build in feedback so workers know whether they are succeeding

Task design is especially relevant in assembly, administration, healthcare, logistics, and customer service. In each of these, work can be streamlined without stripping away all autonomy or increasing stress.

3.3 Tool and equipment design

Tools should support natural movement and minimise force, awkward posture, and precision demands beyond the user’s capability. Good tool design usually considers:

Handle size and shape
Grip force requirements
Weight distribution
Vibration
Edge sharpness
Ease of cleaning and maintenance
Compatibility with user hand size and strength

A poorly designed tool may cause pain even when the task seems simple. A screwdriver with an uncomfortable handle, a mouse with excessive resistance, or a scanner that requires awkward wrist angle can all create cumulative strain.

In digital environments, “tools” include software and interfaces. Button placement, menu structure, error messages, default settings, and colour contrast all affect performance. Human factors professionals therefore study both physical tools and information tools.

3.4 Environmental ergonomics

The environment strongly affects comfort and performance. Important variables include:

Lighting
Noise
Temperature
Humidity
Air quality
Vibration
Space constraints

Poor environmental conditions can amplify fatigue and reduce concentration. For instance, excessive heat increases physiological strain and lowers cognitive performance. Poor lighting can lead to visual discomfort, headaches, and errors. Noise can interfere with communication and concentration.

A useful exam distinction is between comfort and performance. Workers may tolerate uncomfortable conditions for short periods, but the hidden cost is reduced productivity and increased error rates over time.

3.5 Office ergonomics

Office ergonomics is often underestimated because office work looks physically easy. In reality, static sitting, repeated keyboard use, and visually demanding screen work produce a unique pattern of discomfort. Key concerns include:

Chair height and back support
Desk height
Monitor position
Keyboard and mouse placement
Glare and lighting
Break scheduling
Document holder placement
Laptop use without external peripherals

A common mistake is using a laptop as a full-time workstation. Laptops encourage a low screen position and fixed keyboard-screen arrangement, which often forces neck flexion and cramped arm posture. A more ergonomic arrangement usually includes an external keyboard, mouse, and monitor stand.

3.6 Industrial ergonomics

Industrial ergonomics focuses on physical work in settings such as factories, warehouses, construction, maintenance, and processing plants. Key issues include:

Manual handling of loads
Reaching and lifting
Repetitive motion
Forceful exertion
Tool use
Machine guarding
Workstation layout
Shift scheduling

The goal is not to eliminate all physical effort, but to ensure that effort is safe, efficient, and sustainable. A well-designed industrial workspace can reduce injuries, improve throughput, and increase morale.

3.7 Example: warehouse picking process

Imagine a warehouse worker retrieving goods from shelves, scanning items, and stacking them onto a pallet. Problems arise if:

Heavy items are stored too high or too low
A scanner is heavy or awkward to hold
Aisles are too narrow
Targets are unrealistic
Breaks are insufficient
The worker must twist repeatedly when placing items on pallets

An ergonomic redesign might involve:

Storing heavy items between knee and shoulder height
Using lighter scanning devices
Repositioning pallets closer to the picker
Rotating tasks
Reducing repetitive twisting
Monitoring load limits and pace

The result would likely be fewer injuries, lower fatigue, and improved accuracy.

4. Measurement, Assessment, and Intervention

4.1 Why assessment matters

Ergonomics becomes effective when it is measured. Assessment allows the organisation to identify risks, prioritise interventions, and evaluate whether changes actually work. Without assessment, ergonomic improvement becomes guesswork.

Assessment usually examines:

Posture
Force
Frequency and duration of movements
Load handling
Environmental conditions
Cognitive demand
Error patterns
Worker reports of discomfort or fatigue

Different methods are used depending on the situation. Some are observational, some are self-report, and some use measurement instruments or software.

4.2 Observation-based methods

Observational methods are widely used because they are practical and relatively low-cost. They involve watching the work and scoring risk factors. Common observations include body angle, repetition, lifting frequency, reach distance, and awkwardness of movement.

Useful observational approaches often focus on:

Neck flexion
Trunk bending
Shoulder elevation
Wrist deviation
Twisting
Duration of static postures
Frequency of forceful exertion

Observation is valuable, but it has limitations. It may miss subtle cognitive workload, intermittent strain, or the worker’s subjective discomfort. For this reason, many ergonomic assessments combine observation with questionnaires and interviews.

4.3 Self-report tools and worker participation

Workers are often the best source of information about discomfort, difficulties, and workflow breakdowns. Self-report tools can reveal early symptoms before injury becomes severe. Questionnaires may ask about pain locations, frequency, intensity, and task difficulty.

Worker participation is a central principle in modern ergonomics because:

Workers understand the real task, not just the formal job description
They notice small inefficiencies and hazards
They are more likely to support changes they helped design
Participation can improve morale and trust

A top-quality ergonomic intervention is not imposed only from above. It is co-designed with the people who do the work.

4.4 Common ergonomic intervention strategies

Ergonomic interventions can be grouped into several categories:

Intervention type	Purpose	Example
Engineering controls	Change the physical system	Adjustable workbench, lifting aid
Administrative controls	Change how work is organised	Task rotation, break scheduling
Training	Improve knowledge and skills	Safe lifting instruction
Personal equipment	Support or protect the worker	Anti-fatigue mat, supportive device
Design modification	Improve interface or layout	Better software screen layout

Engineering controls are generally stronger than training alone because they reduce risk at the source. Training is still important, but if the task remains physically or cognitively unsafe, training cannot solve the design problem.

4.5 The hierarchy of control in ergonomics

A useful principle in occupational safety is the hierarchy of control, which can also be applied to ergonomics. Controls are generally more effective when they remove the hazard rather than rely on the worker’s behaviour.

From strongest to weakest:

Elimination – remove the hazard completely
Substitution – replace with something safer
Engineering controls – redesign the workstation or process
Administrative controls – change procedures, schedules, or supervision
Personal protective equipment – provide supportive or protective gear

For ergonomics, elimination and substitution are not always possible, but they should be considered before relying on advice like “sit up straight” or “take care when lifting.” Such advice is too weak if the system itself is poor.

4.6 Example: correcting a computer workstation

An employee reports neck pain, shoulder tightness, and headaches after long hours at a desk. Assessment reveals:

Monitor too low
Keyboard too far forward
Chair not adjusted correctly
Glare from a nearby window
No scheduled micro-breaks

A proper intervention would include:

Raise the monitor to eye level
Bring keyboard and mouse close to the body
Adjust chair height and lumbar support
Reduce screen glare with positioning or blinds
Encourage brief movement breaks
Review workload and screen time distribution

The important lesson is that pain may reflect a poor work system rather than a weak body. The intervention should therefore target design, not blame.

4.7 Measuring success after intervention

An ergonomic change should be evaluated using evidence. Useful indicators include:

Reduced discomfort reports
Fewer musculoskeletal complaints
Lower absenteeism
Improved productivity
Reduced errors
Better user satisfaction
Fewer incidents or near-misses

A good intervention sometimes takes time to show full benefit. Workers may need adaptation time, and organisational routines may take time to stabilise. Evaluation should therefore include both immediate and follow-up measurement.

5. Application, Revision Framework, and Exam Preparation

5.1 Linking theory to real workplace problems

Exam success in IOP3704 depends on more than memorising definitions. It requires applying theory to practical cases. Questions often present a scenario and ask for analysis, recommendations, or critique. The best answers identify the ergonomic problem, explain the human factor involved, and propose feasible improvements.

A strong answer usually follows this structure:

Identify the issue
Explain the human limitation or system mismatch
State the likely impact on health, safety, or performance
Recommend targeted ergonomic interventions
Justify why those interventions are appropriate

For example, if the scenario involves a call centre, it is not enough to say “workers are stressed.” A better response would discuss screen fatigue, repetition, static posture, performance monitoring pressure, attention demands, voice strain, and break design.

5.2 High-yield themes to revise

The following themes are central and often transferable across questions:

Fit between people and systems
Anthropometry and percentile-based design
Posture, repetition, force, and static loading
Cognitive workload and mental fatigue
Human error and system design
Workstation design for office and industrial settings
Environmental contributors such as lighting, noise, heat, and vibration
Worker participation in assessment and redesign
Hierarchy of control
Evaluation of intervention effectiveness

These themes should be understood as connected. For instance, poor lighting may increase visual strain, which increases fatigue, which increases error likelihood, which reduces productivity. A good exam answer demonstrates these chains of cause and effect.

5.3 Common exam-style prompts and how to approach them

Prompt 1: “Discuss the importance of ergonomics in the workplace.”

A strong response should cover:

Safety and injury prevention
Efficiency and productivity
Comfort and well-being
Error reduction
Quality improvement
Organisational benefits such as lower absenteeism and improved morale

Prompt 2: “Differentiate between human error types.”

A strong response should define:

Slips
Lapses
Mistakes

Then explain:

Causes
Examples
Implications for prevention

Prompt 3: “Recommend ergonomic improvements for an office workstation.”

A strong response should mention:

Chair adjustment
Monitor height
Keyboard and mouse placement
Lighting and glare
Breaks and movement
Laptop external accessories if relevant

Prompt 4: “Explain how workload affects human performance.”

A strong response should cover:

Mental workload
Attention and fatigue
Errors under pressure
Boredom and underload
The need for balanced demands

5.4 Exam answer quality indicators

Markers typically reward answers that are:

Accurate in terminology
Applied to the scenario
Organised into logical paragraphs
Balanced between theory and example
Critical, not merely descriptive
Specific about interventions and outcomes

Weak answers usually:

List definitions without explanation
Give generic advice without linking it to the case
Ignore organisational factors
Focus only on the worker rather than the system
Fail to show how one issue leads to another

A useful revision strategy is to practise turning each concept into a short scenario-based paragraph. For example, do not just define “static loading”; describe a receptionist sitting in one posture for hours and explain why that posture produces strain even without heavy lifting.

5.5 Compact revision table

Concept	Core idea	Exam reminder
Ergonomics	Fit work to people	Think design, not blame
Human factors	Human behaviour in systems	Include cognitive and organisational issues
Anthropometry	Body measurement data	Use percentiles and adjustability
Human error	Slips, lapses, mistakes	Link error to system design
Workload	Mental and physical demand	Too high and too low are both problematic
Intervention	Change the system	Engineering controls beat advice alone
Evaluation	Check whether change worked	Use symptom, performance, and safety indicators

5.6 A final integrated case: mixed office and digital work

A university administration office uses fixed desks, shared computers, repeated data entry, and long periods of seated work. Staff report neck pain, eye strain, and declining concentration in the afternoon. Errors increase at busy times of the semester, especially when deadlines are tight.

An ergonomic interpretation would note several overlapping issues:

Workstations are not adjustable for different users
Monitors may be too low or too far away
Static posture is maintained for long periods
The task is repetitive and cognitively demanding
Time pressure increases the likelihood of slips
Lack of breaks reduces recovery
Poor interface design may increase cognitive load

A practical improvement package would include:

Adjustable chairs and monitor stands
Better keyboard and mouse placement
Scheduled micro-breaks
Short training on workstation setup
Simplified data-entry interfaces
Task rotation where feasible
Follow-up assessment after implementation

This example captures the essence of ergonomics and human factors: the aim is not just comfort, but the design of reliable, humane, and effective work.

5.7 Final exam memory cues

Use these short cues in revision:

People are not the problem; poor fit is the problem
Design for the 5th percentile reach and 95th percentile clearance where appropriate
Slips, lapses, and mistakes are different
Static posture can be as harmful as heavy lifting
Cognitive overload can cause errors even in simple tasks
Training helps, but design changes help more
Measure before and after intervention
Always connect ergonomics to health, safety, and performance

A strong grasp of these ideas will support both theory questions and applied scenario questions. In exam settings, the highest marks usually go to answers that show clear understanding of the human-system relationship, diagnose the real source of difficulty, and recommend interventions that are both practical and evidence-based.