2. 2
Presentation Objectives
participants will be able to...
• Understand basic concepts of ergonomics
• Identify common musculoskeletal injury risks
• Learn strategies to decrease MSD injury risks
• Address questions on ergonomics and back
safety
5. 5
Job Risk Factors
• Working in awkward postures / positions
• Prolonged sitting and standing
• Bending, reaching, stretching
• Driving for extended periods of time
• Heavy lifting
• Awkward lifting
• Lifting in combination with twisting
• Pushing, pulling, carrying
• Accidents, slips, trips, falls
• Vibration
6. 6
Goals of Ergonomics Program…
Reduce work-related musculoskeletal disorders developed by
workers when their jobs involve...
• Awkward postures
• Static positions
• Reaching
• Bending & Lifting
• Force
• Repetition
• Contact stress
• Vibration
• Repetition
U.S. Department of Labor Occupational Safety & Health Administration
7. 7
What are MusculoSkeletal Disorders?
MSDs are injuries and illnesses that
affect muscles, nerves, tendons,
ligaments, joints or spinal discs.
U.S. Department of Labor Occupational Safety & Health Administration
8. 8
Common Body Parts Prone To
Workplace MSDs
• Back - Lower
• Neck and Upper Back
• Upper Extremities - Arms and Hands
• Lower Extremities - Legs and Feet
10. 10
Musculoskeletal Disorders:
Signs and Symptoms
in general…
• Decreased ROM
• Decreased grip and/or
pinch strength
• Swelling
• Fatigue
• Loss of function
• Numbness
• Burning sensation
• Tingling
• Pain
• Cramping
• Stiffness
French & Zecha, 2005
11. 11
Musculoskeletal Disorders: How & Why?
• Related to intensity of work
• Have biomechanical and physiological factors
• Can occur after weeks, months, years on job
• Can take weeks, months, years to resolve
• Have occupational and non occupational
causes
French & Zecha, 2005
12. 12
Musculoskeletal Disorders: How & Why?
listening to our body…
• Disruption in balance between breakdown and
recovery
• 1st sx….fatigue (of body part)
• 2nd sx…ache
• 3rd sx…pain
• Leading to loss of function
French & Zecha, 2005
13. 13
Adaptation vs. Injury
the fork in the road…
• Adapt
– Soft tissue remodels
– More strength
– More stability
– More endurance
– Discomfort
decreases
• Injury
– Soft tissue breaks
down
– Less strength
– Less stability
– Less tolerance for
use
– Discomfort increases
French & Zecha, 2005
16. 16
Introducing our 2nd focus area for
today…
• Back care
• Posture
• Contact stress
• Repetition
17. 17
Posture check: reaching & bending
it’s all connected and it’s all about physics…
• Load & leverage
• 10# vs. 70# low back
• 15# vs. 45# head &
neck
• Think about posture
– Forward head
– Sitting
– Reaching
19. 19
Posture
Think of posture in terms of joint position
Static and awkward postures lead to:
 Decreased movement
 Decreased circulation
 Increased stress and fatigue
23. 23
Posture check
ask yourself…
•Are you sitting against the back of your chair
while you work?
•Is your head/neck upright and centered over
your shoulders when you look at the screen or
documents?
•Are your shoulders relaxed when keying and
using the mouse?
•Are your arms close by your sides when you
use the keyboard or pointer?
24. 24
Posture check
ask yourself…
•Are your elbows relaxed (100 degree angle)
when using the keyboard or mouse?
•Are your wrists in a neutral position (aligned
with your forearm) when keying or using the
pointer?
•Are you avoiding awkward postures such as
an extended finger or thumb when keying or
using the mouse?
25. 25
Equipment set-up example
risk identification…
Elbow and shoulder away from body, reaching
increased strain on shoulder and wrist
26. 26
Elbow and shoulder more relaxed and closer to body
decreased strain on shoulder and wrist
Equipment set-up example
risk identification…
27. 27
Equipment set-up example
risk identification…
Forward placement of document holders and monitor
prevents excessive turning and bending stress in neck,
upper back and torso
Posture:
keeping it
straight!
28. 28
A word on repetition
• Key issue is recovery time
- the time required for tissue to restore nutrition, replace
cells, dissipate byproducts
- rest breaks
• Some newer research demonstrates that repetition
is significantly less of a problem vs. posture
29. 29
A word on contact stress
At your workstation notice where your body comes
into contact with objects…
Where are your:
•Front & back of knees
•Elbows
•Wrists
•Back
•Behind
•Calves, feet, ankles
33. 33
Is my “ergonomic” potato chip really
ergonomic?
• To be ergonomic a design
must…
• Fit the user
• Be easy to use
• Improve comfort
• Improve performance
• Improve health and safety
• Not just bells and whistles!
35. 35
Chair Basics
• Good lumbar (low back) support
• Comfortable sitting for at least 2 hours
• Chair has 5 point base
• Adjustable arm rests (or none)
• Seat pan is comfortable
• Easily adjustable while sitting
• Appropriate height & depth of seat pan
36. 36
Monitor issues and glare
protect your eyes !
• Eye-to-screen distance at least 18 inches
• Top of screen at eye level or slightly below
• Don’t stare…blink frequently to lubricate
eyes
• Use blinds to control outside light
• Screen colors: dark letters on light
background (IBM blue)
37. 37
Work technique
ask yourself…
•Do you avoid leaning on the wrist rest while keying and
mousing?
•Are you using a light touch to key?
•Are you holding your mouse loosely with your hand and
fingers in a relaxed position?
•Do you let go of the mouse when not using it?
•Do you take 20 second breaks after every 20 minutes
of keying?
38. 38
Work technique
ask yourself…
•Do you take eye breaks and look at a distance every
20 minutes?
•Do you blink while you look at the screen?
•Do you take stretch breaks throughout the day?
•Have you set up your work to encourage alternating
sitting and standing throughout the day?
•Have you optimized your settings on your computer
to make your work easier? (i.e. flicker rate, mouse
speed, font size)
•Do you know how to adjust your keyboard tray and
chair?
39. 39
Laptops
a few words…
Harder on eyes and neck
• Smaller screens
• Lower quality displays
• Lower viewing angle
Harder on wrists on arms
• Narrow keyboard
• Awkward postures
Harder on back
• Carrying can strain back
Risk Reduction Measures
• External keyboards
• Docking stations
• Practice good posture on road
Risk Factors
42. 42
Back Safety & Ergonomics
isn’t just a work thing!
The big picture…
43. 43
Ergonomics isn’t just a work thing!
think “physics & leverage” working around home…
• Washing dishes, pots & pans
• Carrying and loading groceries
• Picking up and carrying kids
• Walking the dog
• Yard work
– Raking, shoveling, sweeping
– Lawn mowing, snow removal
– Wheel barrels
44. 44
Ergonomics isn’t just a work thing!
think of driving your car…
• Elbow resting on door, center console
• Wrist over steering wheel
• Buttock and back pain
• Posture
• Nerve and tissue compression
• Position of legs while driving
• Muscle strain: hamstring tightness
• Decreased circulation
• Upper neck/back tension and pain
• Muscle strain:upper trapezius
• Stress reactions, trigger points
• Eye strain
• Glare
• Dehydration
45. 45
Ergonomics isn’t just a work thing!
think of sleeping in your bed…
• Neck posture
• Shoulder and arm posture
• Wrist posture
• Knee and hip posture
• Back posture
For long periods of time: static and awkward positions,
decreased circulation, increased compression!
46. 46
Ergonomics…
there is no magic solution…
we are all unique in certain ways
• Age
• Gender
• Anthropometrics – Body Size & Shape
– Equipment accommodates 5th% female to
95th% male
• Skill Level
• General Health and Condition
52. 52
• Poor Body Mechanics
• Stressful Living & Working
• Loss of Flexibility
• Loss of Strength
Leading Causes of Back Problems
53. 53
Another cause of back problems…
accidents
It is also possible to injure
your back due to accidents.
54. 54
How do we take care of our back?
• Body Mechanics
• Proper Lifting Techniques
• Exercise
• Stretching
• Improved postures
55. 55
“It’s not how much you lift or move, but the way you do it”!
1) Push vs. Pull
2) Keep Work Within “Strike Zone”
3) Keep Load Close To Body
4) Use Abdominal Bracing
5) Pivot with Feet - Avoid Twisting
6) Team Work vs. Mule Work
Body Mechanics
General Rules:
56. 56
Power Position:
• Wide base of support
• Feet shoulder width apart
• Back straight
• Head and shoulders up
• Bend at hips and knees - NOT BACK!
• Keep load close to body
• Tighten stomach muscles
• Use leg, hip and buttock muscles
• Breathe out with lift
Proper Lifting Technique
Have class participants name the physical demands of their jobs & list them on flip chart.
Examples: sitting, reaching, driving, lifting, standing, typing, phone, computer work, filing, vibrating tools.
Focus on participant jobs.
Again – ask participants to share the aspects of their jobs that involve these risks.
MSDs are problems that affect our musculoskeletal system.
These are the areas of our body that experience the most frequent problems.
Carpal tunnel = wrist problem, median nerve
Rotator cuff syndrome = shoulder problem
Epicondylitis = lateral/tennis elbow, medial/golfer’s elbow
Low back pain – most common MSD injury
Thoracic outlet syndrome – nerve problem, cervical spine/neck/shoulder region
DeQuervains – thumb tendonitis
ROM = “range of motion”
Non-occupational causes= activity we do outside of work, driving, sleeping, playing, household chores – theses all affect our body
This is the typical injury continuum
Adapt = this is what happens when we exercise! We rest, the body recovers, we gain strength.
Injury occurs when we don’t listen to our bodies, we work through pain, do not get required rest and recovery.
Think of posture as “position” of joints. (ie: wrist posture, leg posture, etc.)
Not just standing or sitting erect.
Left diagram demonstrates awkward posture of elbow joint.
This is example of “garden hose being bent…cutting off circulation to hands”
If so, a hands-free headset may be appropriate.
This is an example of a high-risk computer workstation set-up.
This is an example of an ergonomic intervention to address the risk.
Notice the more relaxed posture at shoulder, arm, wrist.
Review VDT checklist
Review Rhoda report & report example
Eye demo exercise (see highlighted handout)
Eye strain
Finger track
Business card…screen height
Ideally, laptops should be used in jobs that require portability and intermittent computer use.
If used in sustained manner, they should at least have an external keyboard.
During deadlines, we tend to stare more at screen (less blinking dries out and strains eyes).
We also tend to stay in one position which leads to decreased circulation and increased muscle strain.