Ergonomics principles in rehabilitation

Ergonomic Principles in Rehabilitation

Dr. Rajal Sukhiyaji (M.PT. in Sports Science)

Contents Introduction The necessity of applying Ergonomics Principles Ergonomics Risk factors and problems

associated with them Types of Ergonomics Injury How to avoid Ergonomics Injury ? Key elements of successful Ergonomics

Program in a workplace Pillars of Ergonomics Design Summary References

What is Ergonomic ???

Ergonomics derived from two Greek words

Ergon means “ WORK “ Nomos means “ LAW “ Ergonomics focuses on the study of

work performance with an emphasis on worker safety and productivity.

Ergonomic

According to OSHA: “Designing the job to fit the workers, instead of forcing the worker to fit the job “

According to Tayyari & Smith: defined as “Branch of science that focuses on obtaining optimal relationships between workers and their work environment.”

Ergonomics emerged as a scientific discipline in the 1940s as a consequence of the growing realisation that, as technical equipment became increasingly complex, not all of the expected benefits would be delivered if people were unable to understand and use the equipment to its full potential.(According to the Institute of Ergonomics and Human factor )

Rehabilitation

A process aimed at enabling persons with disabilities to reach and maintain their optimal physical, sensory, intellectual, psychiatric and/or social functioning levels, thus providing them with the tools to change their lives towards a higher level of independence.

Ergonomics Applies to… Workstation Design—(desks, chairs, space, layout) Work Postures (sitting, standing, reaching, lifting) Work Organization (Pace, Breaks, Variety) Tools, Equipment, and Furniture Design---(body

size, height, gender, promoting neutral postures, reduced vibration, exposure to acceptable lighting, noise, temperature)

Manual Materials Handling—(lifting, lowering, pulling, pushing, carrying and holding materials)

Work Environment—(ventilation, noise, temperature & humidity, lighting and vision)

Anthropometry

Anthropos means “human” and metron means “measure”.

Thus, It is the “measurement of human individuals.”

It is the science of measurement of human body, provides therapists to understand the complexities of the human form and how is interfaces with its environment.

The necessity of applying Ergonomics Principles Ergonomic program is one of the effective

plan taken into account by many employers.

Increase efficiency of the organization

Poorly design working environment can cause the injurious outcome on three various systems on humans’ body such as musculoskeletal system, cardiovascular system and mental system.

Ergonomics Risk factors and problems associated with them Risk factors are defined as actions or

circumstances that enhance the probability of injury to the musculoskeletal system.

Ergonomics Risk Factors (ERF) is situations that exist or created intentionally or unintentionally that could or might contribute to results contravene or against the principles.

Ergonomics risk factors can be divided into seven categories as follows,

Forceful strains Awkward and static postures Vibration Repetition Duration Excessive pressure on nerve or soft

tissue Extreme temperature

Forceful strains

Force is the amount of exertion needed by a person to carry out a task or maintain control of tools or equipments.

It is so crucial to know how to apply this effort to complete our activity.

Awkward and static postures What is the proper posture ???

Head, trunk, arms and legs are aligned with one another.

Awkward and static postures

Awkward postures refer to a situation where the body is under uncomfortable and away from neutral position.

Awkward or unsupported posture can be caused by stretching or shortening of the connective and nervous tissues.

It is harmful whenever they are carried out in the long time.

Causes of Awkward Posture :-

Poor design in work area Poorly considered hand tools Pushing ,pulling and carrying heavy load Performing tasks which require loads or

body parts

Vibration

Vibrations occur when an object oscillates or rapidly moves back and forth about its stationary point, like a swinging pendulum.

Vibrations are defined by the frequency (how fast the object is moving) and the magnitude or amplitude (the distance of the movement).

Repetition Repetitive movements can lead to overuse of

muscles and tendons. 

Muscles and tendons may be subjected to microtrauma that causes pain. 

This is especially problematic if the repetitive movements are performed in an awkward posture. 

In this case, muscles and tendons may actually rub against other bony structures causing wear or breakdown within the muscles and tendons.

Duration Duration factor is considered when the

task is repeated without any break.

The longer duration of the task, the greater the cumulative load on the tissues.

Some remedies such as changing footrest, rest breaks and etc can be effective in reducing damages caused by this kind of ergonomic risk factor.

Excessive pressure on nerve or soft tissue (Contact stress )

Contact stress occurs when an object presses on soft tissue.

The force imposed by excessive pressure on small areas reduces blood flow and nerve transition and can damage the soft tissue.

It can occur from pressing against hard edges or sharp surfaces, supporting excessive weight and gripping tools.

Extreme temperature Muscles fatigue faster in hot conditions

and gripping objects or tools can become difficult to maintain with sweaty palms. 

Alternating between tasks, or taking more frequent breaks from the task may be required when working in hot weather or confined spaces.

In cold conditions, blood flow to the extremities is reduced and consequently muscle performance is reduced.

Loud noise can compromise attention to a task and can create tension within the body. 

Poor visibility may lead to poor hand-eye co-ordination during a task, or may place the body in an awkward position while straining to see properly.

Types of Ergonomics Injury Types of ergonomics injury are referred as

physical and psychological.

Physical ergonomic injuries :- Related to body size and shape, fitness and strength, posture, the senses , stresses and strains on muscles, joint and nerves.

Psychological ergonomics injury :- Related to mental abilities, personality, knowledge and experience.

The most common type of ergonomic injuries and illnesses is known as musculoskeletal disorders (MSDs) relating to physical injury .

MSD’s have been associated with those work related tasks including reaching, awkward postures, lifting heavy objects, using continuous force, working with vibrating equipment, and performing repetitive motions.

How to avoid Ergonomics Injury ?

Designing job in an effective and standard way. Implementing job design needs to be based on some criteria and aspects.

Safety and healthy work practices at the site can be also impressive which should be considered in ergonomics program.

Appropriate work practice and job design can be considered as the fundamental solutions for impeding ergonomic injuries.

Key elements of successful Ergonomic Program in a workplace

There are several elements required for achieving a successful ergonomic program in a workplace:

Pillars of Ergonomics Design

SummaryTraining and education

employee perception, perceptions prompt behavior repeated

behaviors become habits and the formed habits develop attitudinal

labels and culture among workers.

effective in shaping safety culture

develops the worker’s attitude

beneficial in reducing hazards and injuries

reduce the direct and indirect cost of injuries.

References Ergonomics for Therapist – Third edition , Karen

Jacobs Perspectives in Rehabilitation Ergonomics, edited

by Shrawan Kumar, Department of Physical Therapy, University of Alberta, Edmonton, Canada

International Journal of advances in Engineering and Technology, March,2013

University of Utah, Environmental Health & Safety Department, Basic Principles of Ergonomics

International labour Organization, Health and safety at work Ergonomics, 6th June,2012

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