Office Ergonomics
Office Work & Human/Computer
Interactions
Work station design Posture Keyboards Software/human interactions Human Behavior
Office Work & Human/Computer
Interactions
Early studies 1980’s Eye problems Shoulder problems Lower back problems Neck strain Hand & wrist problems
Office Work & Human/Computer
Interactions
1991 study of 420 medical secretaries 63 % reported neck/shoulder pain
51% low back pain
30 % hand/wrist pain
15 % elbow pain
Who’s At Risk?
Nearly everyone, but women report more incidents of discomfort
Low motivation
Poor workstation design
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…
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… Pregnant
Obese
Lack general physical capabilities, such as strength
People who feel as if they lack control over work pace, environment, and communication
Prevention is crucial to Cost Containment
Evaluate all contributing factors=
Hazard Identification
EnvironmentEnvironment
WorkersWorkers Equipment/MaterialsEquipment/Materials
Task/ProcessesTask/Processes
Hazard Prevention
Neutral positioningWorkstation designWork/rest periods
Task rotationExercise
What is neutral positioning?
Non-stressed postures Relaxed, right angles at
Knees, hips and elbows Wrists straight rather than flexed (down) or
extended (up) Lower and upper back supported
Computer Workstations
Key ElementsKey Elements
Good Working PositionsGood Working Positions
Work ProcessWork Process
Workstation EnvironmentWorkstation Environment
Workstation ComponentsWorkstation 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 Impacts repetition Prolonged periods of activity Medical awareness & training
Work Environment
Lighting Glare Ventilation Noise
Workstation Design
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
Avoid sharp edges
Monitor height and angle Glare, poor contrast, etc. are risk factors
Chairs
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
Need to be adjustable in many different directions
Height Tilt of seat pan Angle of back Provide lumbar support Adjustable arms Capacity, seat width
Chairs
Ergonomic Chairs
Chair Specifications Seat
HeightBackrestSeat Size
10 Standard Adjustments
•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
Small Seat
Minimal Contour
Seat Height: 16.5" - 21.5"Backrest: 19.5"W x 22.5"HSeat Size: 19"W x 17"D
Ergonomic Chairs
Chair Specifications
Seat HeightBackrestSeat Size
18" - 23"24"W x 26"H26"W x 21"D
Chair Specifications
Seat HeightBackrestSeat Size
16.5" - 21.5"19.5"W x 22.5"H22.5"W x 17"DDeep Contoured Seat, Knee
Tilt AvailableBig & Tall
Monitors
Viewing Distance: 20”-40” Viewing Angle: 15-20 degrees
below horizontal
Viewing Time Viewing Clarity
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: Split Tented/Angled Negative Slope Supportive Scooped Keep in mind
Keyboard Placement – Height & DistanceDesign & Use
Pointer/Mouse Interactions
For CAD operators Thumb and forefinger problems Change kind of mouse
Thumb joint pain, switch to “Uniball” or three-finger mouse
Keep in mind
Pointer PlacementPointer Size, Shape, & Settings
Wrist/Palm Supports
In general, research supports the idea of resting the hands on some kind of a surface during keying pauses.
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
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
However, wrist rests are not without potential problems
Caution
Wrist/Palm Supports
Not all studies of wrist rests show positive effects
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
Are designed to minimize eye and neck movement by keeping your documents at the proper viewing level
Desks
Work Surface Depth Location of Frequently Used Devices Should be
Located in Repetitive Access Zone
Recommended Zones for Workplace Components
Telephones
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
Other ConsiderationsOther Considerations
Work/rest periods
An element of a good An element of a good prevention strategyprevention 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 & BreaksSome 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
Eyestrain is the most common complaint from computer users
Intensive use Software Interactions
Inadequate or detrimental lighting and monitor conditions Distance to monitor Ambient lighting Glare
Pre-existing eye conditions, including those you may not be aware of
Stress
A study conducted by Cornell UniversityA 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 Task rotation Get a professional eye examination Control the lights & the monitor
Enough light on documents Eliminate glare
Rearrange the workstation Anti-glare screen
Eye Strain
Solving Office Ergonomic Problems
Evaluate non-work stressors Evaluate work stressors
Use checklists Use workers’ compensation claim data Use personal interviews/discomfort surveys Conduct job safety analysis
Observation Measurements
Implement solutions Provide Employee Training
Analyze a problem jobThink 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?Questions?