Ergonomics Review: General Information, Risk Factors, and Musculoskeletal Disorders

1. Ergonomics Review

2. Topics to be covered • General Information • Risk Factors • Musculoskeletal Disorders • Reducing Ergonomic Hazards • Specific Information • Industrial Ergonomics • Office Ergonomics

3. What is Ergonomics? • The word comes from two Greek words, Ergon and Nomos • Designing the job to fit the worker, not forcing the worker to fit the job • Covers all aspects of a job, from physical stressors to environmental factors

4. Ergonomics- General • The main focus of ergonomics is the prevention of musculoskeletal disorders (MSDs) • Current workplace changes have resulted in an increase of MSDs

5. Specific Risk Factors • Awkward Postures • Forceful Exertions • Repetitive Motions • Duration • Contact Stresses • Vibrations • Others

6. MSDs- General • Generally affect a worker's musculoskeletal system • Includes the bones, muscles, ligaments, tendons, and other soft tissues in the back, neck, shoulders, arms, hands, and feet • May also be referred to as Repetitive Stress Injuries (RSIs), Cumulative Trauma Disorders (CTDs), or Repetitive Motion Injuries (RMIs)

7. Common MSDs • Carpal Tunnel Syndrome • Tendonitis • Neck and Back Injuries • Strains and Sprains • Thoracic Outlet Syndrome • Trigger Finger

8. Symptoms of MSDs • pain, numbness, or tingling in hands or feet • pain in wrists, shoulders, forearms, knees, neck, or back • clumsy hands • headaches or eye strain • ringing in ears • soreness or stiffness in joints or muscles • stabbing or shooting pain in arms or legs • swelling or inflammation in affected areas • redness or warmth in affected areas

9. Reducing the Exposure • Engineering Controls • use automated devices to perform certain routine repetitive tasks • maintain equipment to prevent malfunctions • modify workstation design and layout to ensure proper posture • choose tools that reduce musculoskeletal disorder risks through tool size and balance, handle size and position, textured grips, minimal vibration characteristics, and power control.

10. Reducing the Exposure • Work Practice Controls • Break up or vary job content to prevent muscle fatigue • Use muscle stretch exercises • Schedule more breaks to allow muscles to recover from repetitive stresses • train workers on how to minimize the number and extent of MSDs

11. Reduce the Exposure • Personal Protective Equipment • May not be able to engineer out an ergonomic hazard or reduce it through changes in work practices • Examples: knee pads, gloves

12. Ergonomics- Specific • Industrial Ergonomics • Back Safety • Proper Tool Use • Office Ergonomics • Workstation • Environment • Work Process

13. Back Disorders • The most common MSD • The lower back in very vulnerable to injury • Most back injuries are MSDs that result from the combined effect of many stresses and traumas

14. Risk Factors • NIOSH has identified five main risk factors for back injuries • heavy physical work • lifting and forceful movements • bending and twisting • whole-body vibration • static work postures

15. Protect Your Back • Minimize stress from materials handling • review operations to eliminate unnecessary materials handling • keep products on an as-needed basis instead of stockpiling them for future use • shorten the distances that materials must be moved or raised • use mechanical devices and equipment (dollies, pallet jacks, power lifts, etc.) for assistance whenever possible

16. Protect Your Back • Follow proper lifting techniques • lift with legs • keep weight close to body and stand straight • pivot with the load (don't twist at the waist) • Strengthen and stretch muscles • poor physical condition and excessive body weight can greatly increase the risk of a back injury by stressing the lower back and increasing its curvature • Strong abdominal muscles help to support the body and prevent back injuries

17. Proper Tool Use • Improper use and design of hand tools can cause severe damage to the hand and arm • Reduce your risk of injury by using these guidelines to select hand tools • Know your job • Look at your work space • Improve your work posture

18. Know Your Job • Before you select a tool, think about the job you will be doing • Using a tool for something other than its intended purpose often damages the tool and could cause you pain, discomfort, or injury • You reduce your chances of being injured when you select a tool that fits the job

19. Know Your Job- Common Examples • Cutting, pinching, gripping • Examples: pliers, snips, cutters • Striking • Example: hammers • Driving • Examples: screwdrivers, hand wrenches, nut drivers

20. Know your job • Consider whether you need the tool to provide power or precision • Select the tool with the correct handle diameter or grip span

21. Power Tasks • HANDLE DIAMETER for power tasks is 1 1/4 inches to 2 inches • OPEN GRIP SPAN for power tasks is not more than 3 1/2 inches • CLOSED GRIP SPAN for power tasks is not less than 2 inches

22. Precision Tasks • HANDLE DIAMETER for precision tasks is 1/4 inch to 1/2 inch • OPEN GRIP SPAN for precision tasks is not more than 3 inches • CLOSED GRIP SPAN for precision tasks is not less than 1 inch

23. Look at your Workspace • Awkward postures may cause you to use more force • Select a tool that can be used within the space available • Example: if you work in a cramped area and high force is required, select a tool that is held with a power grip Pinch grip: Power grip:

24. Improve your Posture • Awkward postures make more demands on your body • The placement of the work piece may affect your shoulder, elbow, wrist, hand, or back posture • Whenever possible, choose a tool that requires the least continuous force and can be used without awkward postures

25. Improve your Posture- Example • Avoid raising your shoulders and elbows. Relaxed shoulders and elbows are more comfortable and will make it easier to drive downward force • If you are sitting: • If you are standing:

26. Overview of Office Ergonomics • Workstation (chair, monitor & document, keyboard, mouse) • Environment (lighting, glare) • Work Process

27. Workstation- Chair • A properly designed chair should provide appropriate support for the back, legs, buttocks, and arms • The following items are critical to employees who spend extended hours at the workstation 1. Seat position 2. Chair Height 3. Armrest

28. Chair- Seat Position • The seat and backrest of the chair should support a comfortable posture that allows frequent changing of the seating position • The seat pan should be padded and have a rounded “waterfall” edge which reduces contact stress with the back of the legs

29. Chair- Height • The chair should be height adjustable, especially in areas where they are shared by a number of employees • The chair height is proper when the entire sole of the foot can rest on the floor and the back of the knees are slightly higher than the seat of the chair • Knees should be bent at about 90 degrees

30. Chair- Armrest • Armrests should be adjustable so they can be lowered to fit under work surfaces • Armrests should support forearms while the employee performs tasks and should not interfere with movement.

31. Workstation- Monitor and Document • Monitor and document placement is important in creating a comfortable workstation. • Consider the following items in order to reduce awkward head and neck postures, fatigue and/or headaches: 1. Display 2. Source Document Position

32. Monitor- Display • The monitor should be kept directly in front of the user • The topmost line of the screen should be no higher than the user’s eyes • The preferred viewing distance is 18 to 24 inches. If there is not enough table depth to accommodate this distance, install a keyboard extender or tray underneath the desk

33. Monitor- Display (cont.) • Viewing the monitor for long periods of time can cause eye fatigue and dryness • Rest eyes periodically by focusing on an object at least 20 feet away • Stop, look away, blink and/or stretch at regular intervals

34. Document- Source Position • The screen and document holder should be close enough together so the operator can look from one to the other without excessive movement of the head, neck or back

35. Workstation- Keyboard and Mouse • The proper position of the keyboard and mouse is essential in creating a comfortable workstation. Consideration of the following factors can help prevent musculoskeletal disorders such as carpal tunnel syndrome and tendonitis: 1. Height and Orientation 2. Placement 3. Design and Use

36. Keyboard and Mouse- Height and Orientation • The keyboard and/or chair should be adjusted so the employee’s elbows hang comfortably at the side of the body • Shoulders should be relaxed and the wrists should not be bent up or down or to either side • The angle of the keyboard should also be considered

37. Keyboard and Mouse- Placement • The keyboard should be placed directly in front of the user • The mouse should be positioned at the operator's side with his or her arm close to the body • The upper arm should not be elevated or extended while using the mouse

38. Keyboard and Mouse- Design and Use • Wrists should not be bent sideways or up and down while keying • Reduce bending of the wrists by moving the entire arm. • A mouse pad or wrist rest can be used to help maintain straight wrists

39. Environment- Lighting • Inappropriate lighting is a major factor in visual discomforts such as eyestrain, burning or itching eyes, headache, and blurred vision • For optimal comfort, the following factors should be considered: • Amount of light • Contrast of light with environment

40. Lighting- Amount of Light • Bright light on the display screen "washes out" images making it difficult for operators to clearly see the work • Use light diffusers, desk/task lighting, or try removing middle bulbs of 4-bulb fluorescent light fixtures

41. Lighting- Amount of Light (cont.) • Use blinds or drapes on windows to eliminate bright light • You may want to reorient your workstation so that bright lights are not in your field of view

42. Lighting- Contrast with Environment • To avoid high contrast between light and dark areas of the computer screen, work area, and surrounding areas use well distributed light • Use light, matte colors on walls and ceilings in order to better reflect indirect lighting and reduce dark shadows and contrast.

43. Environment- Glare • Glare on the viewing screen may cause eyestrain, headaches and fatigue. The worker may not be conscious of the irritation; however, over the course of a long day, it can cause problems. The following sources of light may cause glare: 1. Direct 2. Reflected

44. Glare- Direct • Orient workstations so that light sources do not reflect on the screen • Use blinds or drapes on windows to help reduce glare • Clean the monitor frequently. A layer of dust can contribute to glare • If nothing else works, you may try a glare screen that attaches to the monitor

45. Glare- Reflected • To limit reflection from walls and work surfaces around the screen, these areas should be painted a medium color and have a non-reflective finish • Tilt the monitor down slightly to prevent it from reflecting overhead light

46. Work Process • Even when the workstation design and environmental factors are at their best, a worker can suffer discomfort and injuries from factors related to the work process. • Prolonged and Repetitive Activities • Inappropriate Production Requirements • Excessive Overtime • Inadequate Medical Awareness • Inadequate Training

47. Prolonged and Repetitive Activities • Although computer work may appear to require little exertion, repetitive movements can lead to pain or injury • Workstations should be provided so employees can change working posture • Rest breaks • Alternative job duties

48. Inappropriate Production Requirements/ Overtime • If standards are set too high, employees may work without taking breaks • This may benefit your department in the short run, but the long term effects may lead to higher injury rates • Take Breaks!!!

49. Inadequate Medical Awareness • Symptoms of injuries should be reported as soon as they start to develop • Consult with a medical specialist who has experience with work-related musculoskeletal disorders (MSDs)

50. Handout- Workstation Checklist • Use this checklist to analyze your workstation