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International
Labour Organization


kuva-9.JPG (324249 bytes)Your health and safety at work

ERGONOMICS

 

 

 

 

 

 

Goal of the Module

This Module provides trainees with basic information on ergonomics. Topics discussed include information on some of the acute and chronic health problems which can result from poor ergonomic conditions at work, some basic ergonomic principles of work involving sitting, standing, and heavy manual work, ergonomic principles of tool design and job design, and the role of the health and safety representative.

Objectives

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At the end of this Module, trainees will be able to:

(1) explain what ergonomics means;

(2) explain some of the ways ergonomics can be used to improve working conditions;

(3) state some common health problems that can result from poor ergonomic conditions in the workplace;

(4) describe some basic ergonomic principles of work which involves sitting, standing, or using tools;

(5) describe some basic ergonomic principles for heavy manual work;

(6) state several recommended principles of job design.

 

What is in this Module

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I. Introduction
II. Common injuries/diseases
III. Basic ergonomic principles

A. Workstation
B. Sitting and chair design
C. Standing workstation
D. Hand tools and controls
E. Heavy physical work
F. Job design

IV. Role of the health and safety representative
V. Summary
Exercise. Identifying problems and developing solutions to ergonomic problems
Appendix I: Lift and carry properly
Appendix II: Job design check-list
Appendix III: What do you do if you think you have a cumulative trauma disorder?
Appendix IV: Evaluate your job for risk factors
Appendix V: Controlling vibration hazards; health survey: whole-body vibration and hand-arm vibration.

I. Introduction

A. What is ergonomics?

More and more work today is being done by machines. This increase in mechanization and automation often speeds up the pace of work and at times can make work less interesting. On the other hand, there are still many jobs that must be done manually, involving heavy physical strain. One of the results of manual work, as well as the increase in mechanization, is that more and more workers are suffering from backaches, neckaches, sore wrists, arms and legs, and eyestrain.

Ergonomics is the study of work in relation to the environment in which it is performed (the workplace) and those who perform it (workers). It is used to determine how the workplace can be designed or adapted to the worker in order to prevent a variety of health problems and to increase efficiency; in other words, to make the job fit the worker, instead of forcing the worker to conform to the job. One simple example is raising the height of a work table so that the worker does not have to bend down unnecessarily to reach his or her work. A specialist in ergonomics, called an ergonomist, studies the relation between the worker, the workplace and the job design.

There are many obvious benefits of applying ergonomics in the workplace. For the worker, the benefits are healthier and safer working conditions. For the employer, the most obvious benefit is increased productivity.

Ergonomics is a broad science encompassing the wide variety of working conditions that can affect worker comfort and health, including factors such as lighting, noise, temperature, vibration, workstation design, tool design, machine design, chair design and footwear, and job design, including factors such as shift work, breaks, and meal schedules. The information in this Module will be limited to basic ergonomic principles for sitting and standing work, tools, heavy physical work and job design.

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For many workers in developing countries, ergonomic problems may not be high on the list of priority health and safety problems they face. However, the large and increasing numbers of workers affected by poor work design make ergonomic issues important. As a result of the importance and prevalence of health problems related to a lack of ergonomics at work, these issues have become points of negotiation for many unions.

Ergonomics applies principles of biology, psychology, anatomy and physiology to remove from the work environment the conditions that may cause workers to experience discomfort, fatigue or poor health. Ergonomics can be used to prevent bad design from being built into a job if applied when a job, tools or workstations are being set up. For example, a worker's risk of developing musculoskeletal injuries can be greatly reduced, or even eliminated completely, if he or she is provided with properly designed hand tools from the time he or she begins a job requiring the use of hand tools.

It is only in recent years that some workers, trade unions, employers, manufacturers, and researchers have begun to give attention to how workplace design can affect the health of workers. Without the application of ergonomic principles, tools, machines, equipment and workstations are often designed without much consideration of the fact that people are of all different heights, shapes and sizes, and have different levels of strength. It is important to consider these differences in order to protect worker health and comfort. Without the application of ergonomic principles, workers are often forced to adapt themselves to poor working conditions.

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Points to remember

  1. Many workers suffer from injuries and diseases that result from manual work and the increased mechanization of work.

  2. Ergonomics looks at ways to make the job fit the worker, instead of forcing the worker to fit the job.

  3. Ergonomics can be used to improve poor working conditions. It can also be used to prevent bad design from being built into a job if applied when a job, tools or workstations are being set up.

  4. Without the application of ergonomic principles, workers are often forced to adapt themselves to poor working conditions.

II. Common injuries/diseases

Often workers are given little choice and are forced to adapt to poorly designed work conditions, which can lead to serious injury to the hands, wrists, joints, back or other parts of the body. In particular, injuries can result from:

Injuries usually develop slowly

The injuries and diseases caused by poorly designed or unsuitable tools and workstations often develop slowly over a period of months or years. However, a worker will usually have some signs and symptoms for a long period of time indicating that something is wrong. For example, the worker may be uncomfortable while doing his or her job, or feel aches in the muscles or joints after going home from work. Additionally, he or she may have many minor muscle strains over a period of time. It is important to investigate these kinds of problems because what may begin as discomfort may lead in some cases to serious disabling injury or disease.

Table 1 on the following page describes some of the most common injuries and diseases caused by repetitive or poorly designed work. Workers need to be provided with information on injuries and diseases associated with the non-application of ergonomic principles so they will know what symptoms to look for and that such symptoms can be work-related.

Table 1.

INJURY

SYMPTOMS

TYPICAL CAUSES

Bursitis: inflammation of the bursa (sack-like cavity) between skin and bone, or bone and tendon. Can occur at the knee, elbow, shoulder. Called “beat knee”, “beat elbow” or “frozen shoulder” at these locations.

Pain and swelling at the site of the injury.

Kneeling, pressure at the elbow, repetitive shoulder movements.

Carpal tunnel syndrome: pressure on the nerves which pass up the wrist.

Tingling, pain and numbness in the thumb and fingers, especially at night.

Repetitive work with a bent wrist. Use of vibrating tools. Sometimes follows tenosynovitis (see below).

Cellulitis: infection of the palm of the hand following repeated bruising, called “beat hand”.

Pain and swelling of the palm.

Use of hand tools, like hammers and shovels, coupled with abrasion from dust and dirt.

Epicondylitis: inflammation of the area where bone and tendon are joined. Called “tennis elbow” when it occurs at the elbow.

Pain and swelling at the site of the injury.

Repetitive work, often from strenuous jobs like joinery, plastering, bricklaying.

Ganglion: a cyst at a joint or in a tendon-sheath. Usually on the back of the hand or wrist.

Hard, small, round swelling, usually painless.

Repetitive hand movement.

Osteo-arthritis: damage to the joints resulting in scarring at the joint and the growth of excess bone.

Stiffness and aching in the spine and neck, and other joints.

Long-term overloading of the spine and other joints.

Tendonitis: inflammation of the area where muscle and tendon are joined.

Pain, swelling, tenderness and redness of hand, wrist, and/or forearm. Difficulty in using the hand.

Repetitive movements.

Tenosynovitis: inflammation of tendons and/or tendon sheaths.

Aching, tenderness, swelling, extreme pain, difficulty in using the hand.

Repetitive movements, often non-strenuous. Can be brought on by sudden increases in workload or by introduction of new processes.

Tension neck or shoulder: inflammation of the neck and shoulder muscles and tendons.

Localized pain in the neck or shoulders.

Having to maintain a rigid posture.

Trigger finger: inflammation of tendons and/or tendon sheaths of the fingers.

Inability to move fingers smoothly, with or without pain.

Repetitive movements. Having to grip too long, too tightly, or too frequently.

Repetitive work is a common cause of musculoskeletal (and stress-related) injuries and diseases. Injuries caused by repetitive work are generally called repetitive strain injuries (RSIs). RSIs are very painful and can become permanently crippling. In the early stages of RSI, a worker may only feel aching and fatigue at the end of the work shift. However, as the condition gets worse, there can be extreme pain and weakness in the affected area of the body. This condition can become permanent and can progress to a point where the worker cannot do his or her job any longer. Permanent RSI can be prevented by:

In some industrialized countries, RSI is often treated with surgery. However, it is important to remember that treating a problem is not the same as preventing it in the first place. Prevention should be the first goal, especially since surgery for RSI often has poor results and, if the worker returns to the same job that caused the problem in the first place, in many cases the symptoms may return — even after surgery.

Injuries are costly

Injuries to workers caused by poorly designed tools or workstations can be very costly in terms of pain and suffering, not to mention the financial loss to workers and their families. Injuries are costly to employers as well. Carefully designing a job from the beginning, or redesigning it may cost an employer some money initially. However, in the long term the employer usually benefits financially. The quality and efficiency of the work being done may improve. Health care costs may be reduced, and worker morale may improve. For workers, the benefits are obvious. Applying ergonomic principles can prevent painful and potentially crippling injuries or illness and make work more comfortable and therefore easier to perform.

See Graphic.

Points to remember about
common injuries/diseases

  1. Forcing a worker to adapt to poorly designed work conditions can lead to serious injury to the hands, wrists, joints, back or other parts of the body.

  2. Vibration, repetitive work, twisting, awkward work positions, excessive force or pressure, lifting or pushing can all cause injuries and diseases to develop.

  3. Injuries and diseases caused by poorly designed or unsuitable tools and workstations often develop over time.

  4. Workers should be provided with information on ergonomics-related injuries and diseases, including what the common symptoms are and what work-related conditions are known to cause them.

  5. Injuries and diseases caused by repetitive work are generally called repetitive strain injuries (RSIs). Applying a number of recommended measures can prevent RSIs from developing.

  6. Injuries associated with the non-application of ergonomic principles are costly to both workers and employers, both in terms of pain and suffering and financially.

  7. Applying ergonomic principles in the workplace benefits both workers and employers.

Continue to Chapter III