1. بسم الله الرحمن الرحيم 1

2. Ergonomics

3. Ergonomics
Is the study of the way in which people interact with equipment in their working environment to improve their comfort , safety and productivity
Or it is the science of fitting jobs to the people who perform them

4. Ergonomic Program Benefits
Decreased injuries ,illnesses
Decreased worker’s compensation costs
Increased efficiency at work

5. Ergonomic Program Benefits
Decreased absenteeism and turnover
Increased physical well being
Improved employee morale

6. Ergonomics Involves knowledge of three key aspects - Anatomical
- Physiological
- Psychological

7. Cumulative Trauma Disorders ( CTDs )
Are Conditions likely to result from lack of attention to ergonomic principles
Develop over a long period of time
It is impossible to predict who will develop CTDs

8. Cumulative Trauma Disorders ( CTDs )
Result from the accumulation of stresses over time
Many off the-job activities can lead to CTDs
Examples are : Tennis , golf , gardening , needle work , etc.

9. Factors affecting CTDs
Contact stress
Is caused by any sharp or hard object putting localized pressure on a part of the body. It will irritate local tissues and interfere with
circulation and nerve function
Excessive heat
Can result in increased fatigue and heat stress

10. Factors affecting CTDs
Extreme cold
Constricts blood vessels and reduces sensitivity and coordination of body parts
Stress and Psycho-social issues
can create increased muscle tension and reduce a person’s awareness of work technique

11. Examples of CTDs Repetitive Strain Injury , RSI Tendinitis
Tenosynovitis
Bursitis

12. Examples of CTDs De Quervain’s disease Carpal Tunnel Syndrome
Work Related Upper Limb Disorders
Lower Back injuries

13. Factors Behind CTDs Position of the body
Force required to perform the task
Frequency of the task

14. Position of the body

15. Body Position Nobody can work in a perfect position all the time
The best position For Tendons & Ligaments are those in which the muscles have the most strength

16. Body Position Body muscles will have the most strength if
- Wrists are straight
- Back and neck are as close to their natural alignment as possible Shoulders are relaxed
- Elbows are near the side and bent at about 90 angle to reach the work

17. Body Position
Static posture occurs when one position is held for a prolonged period of time
The muscles will become fatigued from a lack of blood flow during a static posture
The fatigue can lead to discomfort and even injury

18. Body Position
A neutral body position is safest and most efficient position to work
Awkward posture is a deviation from the neutral position & it puts stress on muscles , tendons and joints

19. Neutral position

20. MUSCLES
TENDONS

21. LIGAMENTS

22. Body Position
Let us discuss the position of the following body parts :
1 – Neck and shoulders
2 – Back
3 – Elbows
4 – Wrist

23. Neck and shoulders position

24. Position of Neck and Shoulders
Neck to be in natural alignment with the spine
Head should not be tilted to one side or turned to the left or right
A good guideline to follow : Ears should be over the shoulders

25. Position of Neck and Shoulders
Shoulders should be relaxed & not raised
Arms not raised
Tension in the neck & shoulders can result from having to hold the head to work at a work station that is too low or too high

26. Position of Neck and Shoulders
The too high work station is the most common source of tension to neck & shoulders
In case of too high work station :
Either to lower the work or to raise the employee
The second option is more easier

27. Back position

28. Back Position
If employees do most of their work standing in one position , there should be a rail or other foot support to permit them to prop one foot up
This position puts the spine in the best alignment to prevent uneven pressures on the discs

29. Back Position
If you have employees who sit for most of the shift , provide them with ergonomically sound chair
Avoid stooping , twisting and over-reaching
Try to eliminate the need for manual handling

30. The Human Spine

31. Twisting

32. Twisting

33. Over - reaching

34. Stooping while handling

35. Manual handling

36. Elbows position

37. Elbows Position Elbows should be at 90 angle without any rotation
of the forearms or bending of the wrists
If arms are extended with elbows at angle greater than 90 , arm muscles will be stretched out , become stiffer & less elastic
If arms are flexed with elbows at angle less than 90 , muscles will be shortened & their ability to contract decrease

38. Wrist position

39. Wrist Position
Applying a very light force very often with the wrist in dangerous positions will put more stress on the tendons that go through the carpal tunnel
Wrists should be as close to the neutral position
as possible

40. Wrist Dangerous Positions
Extended
Flexed
Radial deviation
Ulnar deviation

41. Wrist Position
Tools should be designed and located to allow the wrist to be in the neutral position without any flexion , extension , radial or ulnar deviation

42. Wrist dangerous positions

43. Proper hand & wrist position

44. Force Required to perform the task

45. Force
Force is the amount of physical effort required by a person to do a task or maintain control of tools or equipment
For a job requiring very much force , It is important to reduce the frequency & to use the best position
A small amount of force can be damaging if it is repeated often enough & applied in an awkward position
When tools are easier to grip , the employee does not have to apply as much force

46. How to make the tool easier to grip
Tool handle sized right for the employee’s hand , not too large or too small
Textured or cushioned handles
Flange at the base of the handle to keep the hand from slipping

47. How to grip the load
Pinch grip ( Squeezing an object between the thumb & the fingers)
should not be used to lift heavy objects
A pinch grip produces 3-5 times more force on the tendons in the wrist than a grip with the whole hand
Power grip is preferred , The whole hand used to grip
the load
Use both hands - not just one
Weight of the load to be balanced by both sides of the body

48. Power Tools
Using power tools can significantly reduce the amount of force required to be applied . Power tools has vibration risk
Vibration from power tools can place stress on the tissues of the fingers , hand and arms

49. Frequency of the task

50. Frequency
When a job requires frequent repetitions , it is important for employees to work in the best position & with as little force as possible

51. How to reduce frequency
Task interruption by breaks
Job enlargement , increase the number of tasks each
person performs
Job rotation , employees work at one job part of the day & then go to a different job for the rest of the day

52. Office Ergonomics

53. Office Ergonomics
By applying ergonomic principles to the office setting , risk factors are minimized , productivity is increased and overall workplace quality is improved
The workstation must be adjusted to promote a neutral position while a person works
When adjusting a workstation , keep in mind that all of the equipment interacts
Making one adjustment may alter another

54. Office Ergonomics guidelines
Adjust the Chair
Adjust reach requirements
Adjust focal requirements

55. Office Ergonomics guidelines
Check lighting , noise and temperature
Check work pace and stress levels
Check work processes

56. Office Ergonomics guidelines
Modify wrist / hand motions
Improve neck and back postures
Consider personal preferences

57. Office ergonomics basic criteria
Adequate lighting
Adequate contrast , no glare , or distracting reflections
Distracting noise minimized
Leg room and clearance to allow postural changes

58. Office ergonomics basic criteria
Window covering if needed to minimize glare
Software : Appropriate to task , adapted to user , providing feedback on system status
Screen : stable image , adjustable , readable , glare and reflection free
Keyboard : usable , adjustable , legible

59. Office ergonomics basic criteria
Seat back adjustable
Good lumbar support
Seat height adjustable
No excess pressure on underside of thighs and backs of knees

60. Office ergonomics basic criteria
Foot support if needed
Space for postural change , no obstacles under desk
Forearms approximately horizontal
Wrists not excessively bent ( up , down or side ways )

61. An important Office Ergonomic Principle

63. Workstation operator postural issues

64. The End Thanks