Office Ergonomics
Office Work &
Human/Computer Interactions
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Work station design
Posture
Keyboards
Software/human interactions
Human Behavior
Office Work &
Human/Computer Interactions
Early studies 1980’s
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Eye problems
Shoulder problems
Lower back problems
Neck strain
Hand & wrist problems
Office Work &
Human/Computer Interactions
1991 study of 420 medical
secretaries
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63 % reported neck/shoulder pain
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51% low back pain
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30 % hand/wrist pain
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15 % elbow pain
Who’s At Risk?
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Nearly everyone, but women report more
incidents of discomfort
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Low motivation
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Poor workstation design
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Many short term studies, few long term or
independent studies.
Are some people at greater risk
than others?
Some researchers think so….
Studies quoted on Cornell’s ergo web site
link repetitive motion injuries to…
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Working with the wrists in deviated postures for any
reason: causes compression of the median nerve
Static postures, especially using a pinch grip to hold
something in place
Some studies have shown greater risks
for people who are…
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Pregnant
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Obese
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Lack general physical capabilities, such as
strength
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People who feel as if they lack control over work
pace, environment, and communication
Prevention is crucial to Cost
Containment
Evaluate all contributing factors
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Hazard Identification
Environment
Task/Processes
Workers
Equipment/Materials
Hazard Prevention
Neutral positioning
Workstation design
Work/rest periods
Task rotation
Exercise
What is neutral positioning?
Non-stressed postures
 Relaxed, right angles at
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Knees, hips and elbows
Wrists straight rather than flexed (down) or
extended (up)
Lower and upper back supported
Computer Workstations
Key Elements
Good Working Positions
Work Process
Workstation Environment
Workstation Components
Good Working Postures
•Hands, wrists, and forearms are straight, in-line and
roughly parallel to the floor.
•Head is level, or bent slightly forward, forward facing, and
balanced. Generally it is in-line with the torso.
•Shoulders are relaxed and upper arms hang normally at
the side of the body.
•Elbows stay in close to the body and are bent between 90
and 120 degrees.
•Feet are fully supported by floor or footrest.
•Back is fully supported with appropriate lumbar support
when sitting vertical or leaning back slightly.
•Thighs and hips are supported by a well-padded seat and
generally parallel to the floor.
•Knees are about the same height as the hips with the feet
slightly forward.
Work Process
Task Organization
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Impacts repetition
Prolonged periods of activity
Medical awareness & training
Work Environment
Lighting
 Glare
 Ventilation
 Noise
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Workstation Design
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Chairs
Monitors
Keyboards
Pointer/Mouse
Wrist/Palm Support
Document Holders
Desks
Telephones
Footrests
Elements of good work
station design
Adjustable chairs
 Keyboard height and angle
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Avoid sharp edges
Monitor height and angle
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Glare, poor contrast, etc. are risk factors
Chairs
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Ideas about correct posture go back to 1884
Upright vs. backward leaning, pressure on
disks, lower back
Chair provides support for upper and lower
back
Chairs
Need to be adjustable in many different
directions
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Height
Tilt of seat pan
Angle of back
Provide lumbar support
Adjustable arms
Capacity, seat width
Ergonomic Chairs
Chair Specifications
Seat Height
Backrest
Contour
Seat Size
Small Seat
Minimal
Seat Height: 16.5" - 21.5"
Backrest: 19.5"W x 22.5"H
10 Standard Adjustments Seat Size: 19"W x 17"D
•Pneumatic Seat Height
•Seat Angle or Tilt
•Seat Angle Tension Control
•Backrest Angle
•Backrest Height
•Backrest Depth
•Inflatable Lumbar
•Armrest Height
•Armrest Rotation/Swivel
•Armrest Width
Ergonomic Chairs
Chair Specifications
Seat
Height
Backrest
Seat Size
Chair Specifications
16.5" - 21.5"
19.5"W x
22.5"H
22.5"W x 17"D
Deep Contoured Seat, Knee
Tilt Available
Seat
Height
Backrest
Seat Size
Big & Tall
18" - 23"
24"W x
26"H
26"W x
21"D
Monitors
Viewing Distance:
 Viewing Angle:
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Viewing Time
 Viewing Clarity
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20”-40”
15-20 degrees
below horizontal
Keyboards
The objective is to keep the hands and wrists in as
“neutral” a position as possible
Adjustments, may include tilting or not tilting the
keyboard, wrist rests in front of the keyboard, and
repositioning the entire body
Alternative shapes of keyboards may help:
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Split
Tented/Angled
Negative Slope
Supportive
Scooped
Keep in mind
Keyboard Placement – Height & Distance
Design & Use
Pointer/Mouse Interactions
For CAD operators
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Thumb and forefinger problems
Change kind of mouse
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Thumb joint pain, switch to “Uniball” or
three-finger mouse
Keep in mind
Pointer Placement
Pointer Size, Shape, & Settings
Wrist/Palm Supports
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In general, research supports the idea of resting the
hands on some kind of a surface during keying pauses.
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The use of wrist rests has been associated with reduced
muscle activity in the arms and shoulders, straighter
wrist postures, comfort, and preference.
Wrist/Palm Supports
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Some research suggests that wrist rest users sit in a somewhat
more reclined posture than people without wrist rests, which is
known to be comfortable and healthy for the back
Caution
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However, wrist rests are not without potential problems
Wrist/Palm Supports
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Not all studies of wrist rests show positive
effects
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Use of wrist rest causes the fluid pressure in the carpal
tunnel to rise, sometimes significantly
Use of convex wrist rests, which concentrate pressure
in a small area, are less desirable than broad, flat ones
Benign cysts apparently have been caused by constant
pressure on the wrist
Typists should use them during keying pauses,
not during keying, in order to have free hand
and arm movement and to reduce the amount
of time the wrist is compressed
Document Holder
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Are designed to minimize eye and neck
movement by keeping your documents at the
proper viewing level
Desks
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Work Surface Depth
Location of Frequently Used Devices Should be
Located in Repetitive Access Zone
Recommended Zones for Workplace Components
Telephones
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Head sets can help avoid neck and
shoulder strain for telephone use.
Footrests
Reduces leg strain and promotes
circulation
 Reduces strain on lower back
 Should position your knees to roughly a
90 degree angle
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Other Considerations
Work/rest periods
An element of a good
prevention strategy
Provide regular breaks by inserting a different kind of
task into the routine
Some studies recommend 5 minutes of rest per hour
of typing
Other studies recommend 15 minutes of rest per
four hours of work.
Task Rotation
Alternate other kinds of office tasks,
such as filing, copying
 Caution:
May be just as repetitive as typing
and use the same motions and muscles
 However,
more productive and feel less like an
interruption than “just a break
Task Rotation & Breaks
Some companies have actually installed
software that “shuts down” the system for
regular breaks
Other companies have organized or signaled
breaks
These can be aggravating, as they interrupt a
task in progress
Eye Strain
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Eyestrain is the most common complaint
from computer users
Intensive use
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Inadequate or detrimental lighting and
monitor conditions
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Software Interactions
Distance to monitor
Ambient lighting
Glare
Pre-existing eye conditions, including those
you may not be aware of
Stress
Eye Strain
A study conducted by Cornell University
Showed that there was an increase in the number
of cases of repetitive stress injuries after new and
hard to use software was introduced
Especially if there were multiple screens or fields
on the monitor simultaneously
Eye Strain
Prevention
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Task rotation
Get a professional eye examination
Control the lights & the monitor
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Enough light on documents
Eliminate glare
 Rearrange the workstation
 Anti-glare screen
Solving Office Ergonomic
Problems
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Evaluate non-work stressors
Evaluate work stressors
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Use checklists
Use workers’ compensation claim data
Use personal interviews/discomfort surveys
Conduct job safety analysis
 Observation
 Measurements
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Implement solutions
Provide Employee Training
Analyze a problem job
Think about the role behavior plays in ensuring
proper use and comfort.
A claim of “ergonomic design” will not ensure
improved use or comfort, (or reduced risk factors) if
behaviors have been ignored
For instance, if workers will not use the new tool, it
cannot reduce the risk
Questions?