The document discusses ergonomics, defined as the study of human interactions within their work environment to optimize safety, efficiency, and comfort. It details various types of ergonomics including physical, cognitive, and organizational, and highlights common work-related musculoskeletal disorders (WMSDs) caused by poor job design and repetitive actions. Prevention strategies are also provided to promote healthier work practices and reduce injury risks.

1. Ergonomics
By: Dr. Animesh Gupta
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2. Bernardino Ramazzini
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3. Occupational Medicine
According to WHO
defined as “ that branch of community
medicine, which deals with the study of health
promotion, health protection & maintenance of
highest degree of physical, mental & social well-
being of workers in all occupations”
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4. What is Ergonomics?
 ERGO= “work”
 NOMICS= “rules” or “laws”
 Ergonomics literally means
“the laws of work”
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5. What is Ergonomics?
 It is the study of humans at work in order to
understand the complex relationship among
people, machines, job demands and work
methods in order to minimize gaps between task
demands and human capacities in activities of
work and daily living. [Maxcy-public health]
 Ergonomics as the science of “designing the job
to fit the worker, instead of forcing the worker to
fit the job. [International Ergonomics Society]
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6. Ideally, ergonomics:
– Makes the job safer by preventing injury and illness
– Makes the job easier by adjusting the job to the
worker
– Makes the job more pleasant by reducing physical
and mental stress
– Saves money
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7. History
• As early as 18th century doctors noted that
workers who required to maintain body
positions for long periods of time developed
musculoskeletal problems.
• Within last 20 years research has clearly
established connections between certain job
tasks and MSD.
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8. Specialization
• Physical ergonomics is concerned with human
anatomy, and some of the anthropometric,
physiological and bio mechanical characteristics
as they relate to physical activity.
• Cognitive ergonomics is concerned with mental
processes, such as perception, memory,
reasoning, and motor response, as they affect
interactions among humans and other elements
of a system.
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9. • Anthropometry is concerned with the
measurement and statistical characterization of
body size in the context of workplace and task
dimensions.
• Provide important information to the designers of
clothing, furniture, machines, tools, and
workstations.
• Organizational ergonomics is concerned with the
optimization of socio-technical systems, including
their organizational structures, policies, and
processes.
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10. • Environmental ergonomics is concerned with
human interaction with the environment.
• The physical environment is characterized by
climate, temperature, pressure, vibration,
light.
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11. Basic Ergonomic Principles
To assess the fit between a person and their
work, ergonomists consider :
 The job being done and the demands on the
worker
 The equipment used (its size, shape, and how
appropriate it is for the task)
 The information used (how it is presented,
accessed, and changed)
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12. HEALTH OF WORKER
Health of worker is influenced by 3 factors
1.Occupational (working) environment.
2.Domestic environment
3. Social security & welfare measures
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13. Occupational (working)
Environment
• Man with machines
• Man with environment
(physical, chemical and
biological agents)
• Man with man
Environment
ManMachine
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14. A) Man with Machine
• Poor installation of machines
• The unguarded
• Protruding and moving part
• Poor maintenance
• Lack of safety measures.
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15. B) Man with Environment
Man and Physical, Chemical and Biological
agent.
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PHYSICAL CHEMICAL BIOLOGICAL
Heat Toxic dust Virus
Light Gases Bacteria
Noise Parasite
Ionizing
radiations
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16. C) Man with Man
Includes “Psychosocial factor” i.e. human
relationship among workers themselves and
authority over them.
Examples :-
I. Nature of work, service conditions
II.Job satisfaction
III.System of Payment
IV. Welfare conditions
V. incentives
VI. Union activities
This constitute psycho-social environment
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17. ERGONOMIC STRESS AREAS
Knee
Hip
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18. Work - Related Musculoskeletal
Disorders (WMSDs)
• These are MSDs that are caused or made worse by
work methods and environment.
• They occur when the physical capabilities of the worker
do not match the physical requirements of the job.
• Common MSDs are
a) Tendonitis
b) Epicondylitis (Tennis or Golfer’s Elbow)
c) Bursitis
d) Carpal Tunnel Syndrome
e) Back Strain.
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19. • Work - related MSDs are also known as
Repetitive Strain or Stress Injury (RSI)
Repetitive Motion Injury (RMI), Cumulative
Trauma Disorder (CTD), Overuse Syndrome or
Activity - related Pain Syndrome.
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20. Causes of MSDs
a) Repetition : Performing the same motion or group
of motions excessively.
b) Awkward Postures or Postures outside of neutral :
Neutral is the optimal position of each joint that
provides the most strength and control.
c) Static Postures : Holding the same position or using
the same muscles for extended periods of time.
d) Cold Temperatures : Working in environments
below 68°F can cause nerve damage.
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21. e) Forceful exertions : A strong physical exertion
produces tension by muscles and is transmitted
through tendons.
f) Vibration : Single Point Hand and Arm exposure
results from vibrating objects such as power tools.
h) Compression : Soft tissue is compressed between
the bone and a hard or sharp object.
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22. h) Poor work-Station design : It is a risk factor for the
development of upper limb disorders.
Several reports have appeared in the literature of
upper limb disorders such as tenosynovitis, lateral
epicondylitis and resulting from mouse use.
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23. • The use of mouse results in abduction and
flexion at the shoulder, flexion of the elbow
and resting of the wrist on the mat along with
ulnar deviation for standard tasks.
• The prevention of problems involves ensuring
that the user handles the mouse within his or
her normal zone of comfort
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24. Signs and Symptoms of MSDs
Common Signs and Symptoms of MSDs are
Painful aching joints, muscles,
 Tingling or numbness,
 Fingers or toes turning white,
Shooting or stabbing pains,
Swelling or inflammation,
Stiffness or difficulty moving,
Burning sensation or Pain during the night.
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25. Carpal Tunnel Syndrome
• It is associated with exposure to some workplace hazards.
• Pressure on the median nerve as it passes under the
flexor retinaculum may lead to
the development of a clinical
picture compromising pain and
paraesthesiae in the thumb,
index and middle fingers
which is often worse at night.
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26. • Wasting of the small muscles of the hand
supplied by the median nerve may occur if the
condition remains untreated for some time.
• Nerve conduction studies are often used to
assist the diagnosis.
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27. Pre - Patellar Bursitis
• Occupational disorders due to repetitive strain
are not new.
• Repeated kneeling and crawling could lead to the
development of inflamed pre - patellar and pre –
tibial bursae.
• This condition arises as a result of manual labour
causing excessive pressure or friction in the area
of the knee.
• Workers who have to kneel repeatedly in their
jobs may suffer from bursitis at the knee.
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28. Back Pain and Work
• Workers whose jobs involve manual handling.
• Although the aetiology of back pain is complex, studies have
shown that repetitive overuse and postural factors
resulting from systems of work are associated with
increased prevalence rates.
• The prolonged maintenance of abnormal postures also
causes marked increases in pressures on the spine because
of the protective responses of the supporting muscles.
• Consequently, guidelines on manual handling should not
merely focus on weights to be lifted, but should also include
an assessment of the associated ergonomics.
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30. Pregnancy and Ergonomics
• A number of studies have looked at the risk to
the mother and foetus from physically tiring
work and strenuous exercise.
• The former has a reported association with
amenorrhoea, and the latter may lead to an
increased risk of abortion, stillbirth and foetal
growth retardation.
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31. • The ergonomic aspects of the developing
pregnancy and the resulting reduced flexibility
and movement also need to be taken into
account when assessing the job, and different
recommendations may be appropriate at
different stages of the pregnancy.
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32. Some important characteristic of WRMSDs :
1. Their pathogenesis involves both mechanical and
physiological processes
2. Weeks, months, and years may be required for them
to develop
3. Weeks, months, and years may be required for
recovery, and in extreme cases, recovery may never
be complete
4. Their symptoms are often nonspecific, poorly
localized, and episodic
5. They often go unreported
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33. Prevention of MSDs
The principles involved in prevention of MSDs lies in
good Ergonomics and the motto ‘Work Smarter, Not
Harder!’
This can be achieved by the following principles :
 Work in neutral postures
 Reduce excessive force & repetition
 Keep everything in easy reach and at proper heights
 Keep warm
 Minimize static unsupported postures and pressure
points
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34. Methods of Reducing Repetition are :
a) Break up the repetitive components of a job.
b) Switch frequently between tasks.
c) Find a different tool that makes the job easier.
d) Let the tool or automation do the work
instead of the body.
e) Introduce leisure activities that have different
physical demands than work activities.
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35. Methods of Reducing Force :
To reduce the force or exertion required to
perform specific activities, use the appropriate
tool for the job and maintain tools in good
working order.
For example
 blades should be kept sharp
 A slippery surface requires extra grip strength to
hold the object
 Avoid sudden impact, jerking, or sudden start -
stop movements
 when lifting or moving objects, keep them close
to your body; push rather than pull.
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37. • Proper posture ensures that one keeps
reaching to a minimum. This can be done by
assuring proper fit of the chair.
• There should be support for the lower back.
• Height should be adjustable in relationship to
the work surface so that the shoulders are
relaxed and the elbows are positioned at the
side of the body (in - line with the shoulders).
Methods of Reducing Awkward Positioning &
Improving Posture
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38. • The work should be positioned at a height
that allows the elbows to be open slightly
greater than 90 degrees.
• A foot - rest should used when necessary.
• The work should be positioned directly in
front of the body to avoid excessive reaching
or turning.
• Frequently used items should be within an
easy reach.
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39. • Tools that fit the hand well and/or are shaped
to help maintain the neutral wrist position
should be used.
• One of the best ways to prevent injuries is to
keep a relaxed and neutral posture while
working.
• For those who work at a desk or on a
computer, the forward head and rounded
shoulder posture is prevalent
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40. However the following are recommended :
The head should be upright with the neck
relaxed.
The monitor should be at a height that allows
you to view it directly in front of you, not
looking up or looking down or to one side or
the other.
Use a copy holder if you work input
information from hard copies.
The ears, shoulders and elbows should be in
vertical alignment.
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43.  The shoulders should be relaxed, not
elevated.
Arm rests are optional. If you do use arm
rests, position them at a height that does not
push your shoulders towards your ears.
 The keyboard and most work should be
positioned at a level just slightly below elbow
level.
However, depending on the type of work, this
may need to be adjusted.
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44. The wrists should be in the neutral position
flat and straight. They should not be bent
forward or back, or angled to one side or the
other.
 The fingers should be relaxed.
Do not pound on the keyboard.
Use the lightest touch possible to activate the
keys or any tool control
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45. Seating in the Workplace :
• Ideally, seats should be personal to the
individual worker and move with him or her
where necessary, but where this is not possible,
adjustable seating should be provided at every
workstation.
• The lumbar region needs to be supported to
decrease disc pressure.
Providing both a seat back that inclines
backwards and has a lumbar support is critical
to prevent excessive low back pressures.
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46. • The lumbar support of 5 cm means the chair
backrest supports the lumbar by sticking out 5
cm in the lower back area.
• Another key to reducing lumbar disc pressure
is the use of armrests.
They help by putting the force of your body not
entirely on the seat and back rest, but putting
some of this pressure on the armrests.
• Arm-rest needs to be adjustable in height to
assure shoulders are not overstressed.
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49. Benefits of Ergonomics
• Decreased injury risk
• Increased productivity
• Decreased mistakes/rework
• Increased efficiency
• Decreased lost work days
• Decreased turnover
• Improved moral
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50. References
1. Rajvir Bhalwar. Text book of Public Health &
community Medicine. 1st edition. AFMC Pune & WHO
Publications, 2009, 1291-1293
2. Wallace/Maxcy- Rosenau- last, Public Health &
Preventive Medicine, 15th edition, TMH Publication,
2008, 763-778
3. Roger Detels. Oxford Textbook of Public Health, 4th
Edition, OkDokey Publications, 2002, 2163-2197
4. International ergonomics association (www.iea.cc.
Last accessed on 27/09/13, 10:00pm)
5. Practical Demonstrations of Ergonomic Principles.
www.cdc.gov/niosh
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51. Thank You6/6/2017 51