1. BY FREDRICK M CHITANGALA MSC, MPH, BA
ERGONOMICS
BY FREDRICK M CHITANGALA
MSC, MPH, BA
10/11/2018

2. Session Objectives You will be able to:
Understand the principles of ergonomics
Recognize the risk factors, signs, and symptoms of musculoskeletal disorders (MSDs)
Understand a program for identifying, reporting, and controlling MSDs
Know how to protect yourself from MSD injuries and reduce your risk
Appreciate the anatomy of a human being
Slide Show Notes
This session has several objectives. By the end of it, you will be able to:
Understand the principles of ergonomics;
Recognize the risk factors, signs, and symptoms of musculoskeletal disorders, or MSDs;
Understand our program for identifying, reporting, and controlling MSDs; and
Know how to protect yourself from MSD injuries and reduce your risk of getting them.
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3. WHAT IS ERGONOMICS?
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4. WHAT IS IT?
According to the Polish Ergonomics Society, the term Ergonomics was originally coined by Wojiech Jastrzebowski, a polish educator and scientist almost 150 years ago. 
Today, the term ergonomics is becoming more and more common, there are
ergonomic chairs,
ergonomic pens and 
ergonomic toothbrushes;
basically everything these days is Ergonomically designed.  In more practical terms, the concept of ergonomics has come to mean finding ways to work smarter-not harder and Fit the work to the worker.  In other words, ergonomics is the study of the physical and cognitive demands of work to ensure a safe and productive workplace.
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5. WHAT IS ERGONOMICS?
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6. ERGONOMICS-What is it? Derived from two Greek words:
“Nomoi” meaning natural laws
“Ergon” meaning work
Hence, ergonomists study human
capabilities in relationship to work demands
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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 RSI or MSD.
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8. Ergonomics
Ergonomics, also known as human engineering or human factors engineering, the science of designing machines, products, and systems to maximize the safety, comfort, and efficiency of the people who use them.
Ergonomists draw on the principles of
industrial engineering,
psychology,
anthropometry (the science of human measurement), and
biomechanics (the study of muscular activity)
to adapt the design of products and workplaces to people’s sizes and shapes and their physical strengths and limitations.
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9. 10/11/2018

10. Ergonomists also consider the speed with which humans react and how they process information, and their capacities for dealing with psychological factors, such as stress or isolation.
Armed with this complete picture of humans interaction with their environment, ergonomists develop the best possible design for products and systems, ranging from the handle of a toothbrush to the flight deck of the space shuttle.
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11. Ergonomists view people and the objects they use as one unit, and ergonomic design blends the best abilities of people and machines.
Humans are not as strong as machines, nor can they calculate as quickly and accurately as computers.
Unlike machines, humans need to sleep, and they are subject to illness, accidents, or making mistakes when working without adequate rest.
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12. But machines are also limited—cars cannot repair themselves, computers do not speak or hear as people do, and machines cannot adapt to unexpected situations as humans.
An ergonomically designed system provides optimum performance because it takes advantage of the strengths and weaknesses of both its human and machine ccomponents.
In general, ergonomics deals with the interaction between humans and such additional environmental elements such as heat, light, sound, atmospheric contaminants and all tools and equipment pertaining to the work place.
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13. Ergonomics has the following advantages:
1. There will be more efficient operations
2. There will be fewer accidents
3. There will be reduced training time
4. There will be fewer costs of operations
5. There will be more effective use of workers or personnel.
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14. 10 Principles of Ergonomics
Refer to the notes downloaded separately
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15. THE GOAL OF ERGONOMICS
The goal of "ERGONOMICS" or human factors ranges from making work safe to humans, and increasing human efficiency and wellbeing.
To ensure a continuous high level performance, work system must be tailored to human capacities and limitations measured by anthropometry and biomechanics.
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16. Ergonomic Hazards
Between 10% and 30% of the workforce in industrial countries and between 50% and 70% in developing countries may be exposed to heavy physical workload or to unergonomic working conditions such as lifting and moving of heavy items or repetitive manual tasks.
Repetitive tasks and static muscular load are found in many industrial and service occupations.
In many industrial countries musculoskeletal disorders are the main cause of both short-term and permanent work disability, which can cause economic losses that may amount to 5% of the GNP.
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17. Most exposures can be eliminated or minimized through mechanization, improvement of ergonomics, and better organization of work and training.
In particular, the growing numbers of elderly workers and the female workforce require constant vigilance from those responsible for the work organization.
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18. Improving the conditions of the work environment and opportunities for providing workers’ health, safety and wellbeing essentially means contributing to sustainable improvement of ergonomics.
Local perceptions about ergonomics in many countries have not captured headlines in the newspapers.
However safe and hygienic workplaces contribute to sustainable development and this issue can be raised through proper media exposure.
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19. Principles of biomechanics
It deals with the functioning of the structural element of the body and the effect of external and internal forces on various parts of the body.
Taking an example of "lifting" an object from the ground biomechanics seek relevant information:
1. What is the task to be performed (task variable)
2. Would the person be able to do the task (human variable)
3. What is the type of work environment (environmental variable)
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20. Task variable
• Location of object to be lifted • Size of object to be lifted • Height from which and to which the object is to be lifted • Frequency of lift • Weight of object • Working position
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21. Human Variable
• Sex of worker • Age of worker • Training of worker • Physical fitness of worker • Body dimension of worker
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22. Environmental variable
• Extremes of temperature (hot/cold) • Humidity • Air contaminants
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23. Work physiology
People perform widely different tasks in daily work situation.
These tasks must be matched with human capabilities to avoid "over loading" which may cause the employee to breakdown, suffer reduced performance capability or even permanent damage.
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24. Matching work to people
It is important to match human capabilities with the related requirements of a given job.
If the job demands are equal to the worker's capabilities or if they exceed them, the person will be under much strain and may not be able to perform the task.
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25. Work classification
The work demands are classified from light work to extremely heavy in terms of energy expenditures per minute and the relative heart rate in beats per minute.
For example the energy requirement for light work is 2.5 Kcal/minute and the heart rate is 90 beats rate per minute, while extremely heavy work energy requirement is 15 Kcal/minute and heart beat is 160/minute.
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26. Workstation design
Workstation means the immediate area where the person is performing his/her duties.
The goal of designing a workstation is to promote ease and efficiency of the person’s performance.
Productivity will be affected if the operator is uncomfortable and the workstation is awkwardly designed.
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27. Workplace design
Workplace is the establishment or department where the person or worker is performing his/her duties.
The most basic requirement for a workplace is that it must accommodate the person working in it.
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28. Specifically this means that:
The workspace for the hands should be between hip and chest height in front of the body.
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30. Ergonomic chairs Adjustable back height and angle Adjustable arm rests
Adjustable height
Five star base
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31. Unsatisfactory “Design”Workstation
Reaching for mouse
Monitor too low
Keyboard too high, wrists bent
Chair too high, feet should be flat on the floor or on a foot rest
Document holder too far back
No arms on the chair
Bad posture, leaning forward
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32. Specifically this means that:
Lower location are preferred for heavy manual work.
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33. Specifically this means that:
Higher locations are preferred for tasks that require close visual observations.
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35. When this is accomplished:
Another key ergonomic concept is that workplace should be designed relating the physical characteristics and capabilities of the worker to the design of equipment and to the layout of the work place.
When this is accomplished:
There is an increase in efficiency
There is a decrease in human error
Consequent reduction in accident frequency.
Design is accomplished after learning what the worker's job description will be, kind of equipment to be used for that process and the biological characteristic of the person (worker).
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36. Effects of non ergonomic working conditions
• Tendosynovitis • Bursitis • Carpal tunnel syndrome • Raynaud’s syndrome (“white fingers”) • Back injuries • Muscle strain
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37. To avoid ergonomic hazards the following points should be considered:- • Sensibility and perceptibility (visual,audible,tactile) • Kinetic ability and muscular power or strength • Intelligence • Skill • Ability to learn a new technique of skill • Social and group adaptability • Kinetic conditions (body size or physical constitution)
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38. • Effect of environmental conditions on human ability • Long term short term or short term adaptable limits of man(desirable or normal, compensatory or fatal) • Reflexion and reaction patterns • Mode of living (custom) and sex distinction • Racial differences • Human relationship • Factors that affect on synthetic judgment
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39. A Bit of Anatomy !!
Overuse and small repetitive movements ie: CTD, RSI, MSD disturb balance of muscles, tendons, ligaments and nerves
Brachial plexus: nerve group that supply muscles and skin of UE, course down side of front of neck and become median, ulnar and radial nerves.
Nerves send signals to muscles to contract
When nerve compressed feel sensation somewhere b/w point of compression and fingertips
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40. What causes Nerve Compression or Entrapment?
Repeated motions
Tight muscles
Inflammation of surrounding tissues
Misalignment of the nerve
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41. What are 4 Common Nerve injuries?
Thoracic Outlet Syndrome: brachial plexus (A network of intersecting blood vessels or intersecting nerves or intersecting lymph vessels)compression d/t muscle tightness side of neck from poor head position or slumped posture.
S/Sx: numbness/tingling in hand, made worse w/overhead activities or cradling phone b/w ear and shoulder
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42. Nerve injuries (cont)
Radial tunnel syndrome: compressed radial outside of elbow d/t repetitive wrist & finger extension or turning of forearm
S/Sx: Sensations from elbow to base of thumb w/ wrist weakness a common sx
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43. Nerve injuries (cont)
Cubital tunnel syndrome: ulnar nerve compression inside of the elbow d/t repetitive bending of elbow or resting your elbow on a hard surface
S/Sx: numbness or tingling and inside of arm w/ tingling to ring & little fingers
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44. Nerve injuries (cont)
Carpal tunnel syndrome: compression of median nerve at level of carpal tunnel
Where is carpal tunnel? wrist by ligament over the carpal bones in hand
S/Sx: numbness or tingling in thumb, index, or middle finger & ½ of ring finger; often night by hand “falling asleep”
Sx increased by driving or attempting to hold objects; dropping objects is a common complaint
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45. Tendons and Tendonitis
Tendons are connective tissue that attach muscle to bone; have little stretch or rebound
Tendon overuse, static or prolonged position=inflammation or tendonitis
Tendons of wrist & hand very high risk for injury w/ overuse
“Tennis elbow” or lateral epicondylitis affects finger extensor tendons outside of elbow
“Golfer’s elbow” or medical epicondylitis affects finger flexor tendons inside of elbow
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46. PREVENT, PREVENT, PREVENT !!!
What to do ??
PREVENT, PREVENT, PREVENT !!!
Warm up & stretch before activities that are repetitive, static or prolonged
Take frequent breaks from ANY sustained posture every minutes
Respect pain positions or stop painful activity
Recognize early signs of inflammatory process, & tx early
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47. Maintain Neutral Posture
Maintain erect position of back & neck w/ shoulders relaxed
Position equipment & work directly in front of and close to your major tasks
Keep upper arms close to the body, elbows degrees
Keep feet flat on floor, upper body weight resting on “sits bones”
Wrists as neutral as possible; safe zone for wrist movement is 15 degrees in all directions
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48. Body Mechanics, in summary
Use the largest joints & muscles to do the job
Use 2 hands to lift rather than one, even with light objects and tasks.
Avoid lifting w/ the forearm in full pronation (palm down) or supination (palm up)
Slide or push & pull objects instead of lifting
Keep reaching to a minimum
Carry objects close to body at waist level
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49. Anatomy and physiology
Muscles
All physical work is done by muscles, in which the necessary energy is created.
The first task of the muscles is to maintain the body in the required posture (upright, seated, kneeling, and so on) and then to effect the various movements.
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50. It is through them that useful work is finally done.
Muscles work by alternating contraction and relaxation of the component fibres, resulting from chemical action.
Muscle fibres, which are mostly arranged in groups or bundles in different parts of the body, cause various movements by acting on the bones.
Muscles also cause movements in internal organs.
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51. The combustion residues include lactic acid, water and carbon dioxide.
The energy required to contract the muscle fibres is provided by the oxidisation of glucides.
The combustion residues include lactic acid, water and carbon dioxide.
Since the chemical reactions take place within the fibres themselves, it becomes necessary for the oxygen and the fuel to be brought to these fibres and for the waste products of combustion to be removed, either to be discharged outside or to be reintroduced in a regeneration cycle.
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52. The working capacity of muscle therefore depends
on the number of fibres (musculature),
the capacity of the transport routes (arteries and veins),
the speed of the transport (blood flow),
the functioning of the regulatory system which has to harmonise the physiological phenomena with the effort exerted, and the pulmonary function which ensures the renewal of the oxygen in the blood and the elimination of gaseous waste.
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53. To effect movements of the body, muscles require a firm anchorage;
Bones and joints
To effect movements of the body, muscles require a firm anchorage;
bones may therefore be considered as being practically rigid.
To a certain extent they are also elastic, especially in young persons.
This elasticity, however, does not play any part in work, it is needed to take the strain of heavy loads.
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54. If the elasticity is insufficient, as is often the case in accidents, a bone will break.
Most bones in the body are connected by joints (such as the knee, the hip and the elbow), or they are semi-rigidly connected by ligaments or cartilage (as the ribs are to the upper part of the spinal column), or they are fastened together like the bones of the skull, whose purpose is to protect the brain.
The spinal column has quite a special structure. The vertebrae are so shaped that the upper part of the body can assume the most widely differing positions in relation to the lower part, and it can also rotate independently.
There is a special reason for this structure, in that the spinal column protects the abdominal organs.
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55. Work Practice Controls
Proper lifting techniques
Good postures
Alternate repetitive tasks
Use breaks to divide up “heavy” work
Stretching/exercise
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56. Lowering The Risk Of Injury
Control 3 types
Engineering
Proper Equipment
Administrative
Proper Staffing
Work practice
Good work habits
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57. Engineering Controls
Supply proper equipment i.e. ergonomically designed tools
Maintain equipment i.e. lubricate and repair
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58. Administrative Controls
Assure adequate staffing
Purchase proper equipment
Rotate “heavy” or repetitive jobs
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59. Proper Lifting Techniques
Step One
Test the load to get an indication as to how heavy the object is.
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60. Proper Lifting Techniques
Step Two
Stand close to the load with your feet spread apart about shoulder width, with one foot slightly in front of the other for balance.
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61. Proper Lifting Techniques
Step Three
Squat down bending at the knees (not your waist). Keep your back straight.
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62. Proper Lifting Techniques
Step Four
Get a firm grasp of the object before beginning the lift.
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63. Proper Lifting Techniques
Step Five
Begin slowly lifting with your legs by straightening them. NEVER twist your body during this step.
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64. Proper Lifting Techniques
Step Six
Once the lift is complete, keep the load close to your body to prevent straining the lower back.
If you must turn while carrying the load, turn using your feet-not your torso
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65. Proper Lifting Techniques
Step Seven
To place the object below the level of your waist, follow the same procedures in reverse order.
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66. Alternatives To Lifting
Ask a co-worker for help.
For difficult lifting tasks, keep these options in mind:
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67. Alternatives To Lifting:
Use a cart but keep this in mind; Pushing a load is easier on the back than pulling. When pushing a cart
Stay close to the load
Don’t lean forward
Use both arms
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68. Alternatives To Lifting
If you must pull the cart:
Face the object squarely, with one foot at least 12 inches in front of the other
Keep your back straight
Bend your knees slightly and pull in a smooth motion.
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69. Safety Tips For Lifting
Don’t lift objects over your head
Don’t twist your body when lifting or setting an object down
Don’t reach over an obstacle to lift a load. Move whatever is in the way or go around it.
Pace yourself to avoid fatigue when doing heavy work for a long period of time.
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