Cornell University Ergonomics Web
Some Ergonomic Considerations when Designing a Computer
There is a wide variety of office furniture to choose from and all of it
claims some ergonomic design merit. Here are some common designs and some
questions and considerations for comparing these designs.
Split-height, angle adjustable worksurface:
- Integrated into workstation furniture design.
- Not retrofittable.
- When the surface is angled down for neutral hand position on the
keyboard the angle may not be ideal for a neutral hand position on the
- If the surface is angled down the mouse runs off (a trackball can
- Mouse use will always be external to the keyboard so there's more arm
abduction than a surface that articulates over the keyboard or a keyboard
with an integrated mousepad (e.g. Jasper Freeboard)
- You lose primary desk real estate in front of the person (for documents
- You no longer have a uniform flat desk worksurface.
- You end up sitting closer to the desk so the screen needs to be moved
back - the viewing distance from eye to screen is a constant for a person
but different between people, if the screen is at a fixed distance then with
a keyboard tray that is easily adjusted each user can achieve their optimal
viewing distance because the tray can be moved in/out - this also means you
can have narrower worksurfaces that work just fine as the tray slides out.
- Height and angle adjustment mechanisms can be are coupled in some way
and may not easy to use.
- There's usually no user feedback (i.e. numerical indicator) on the slope
angle of the surface.
- No palm support \to facilitate neutral wrist posture.
- Expensive and locks furniture into one design that may not accommodate
changing technology and cannot be retrofitted..
Height and angle-adjustable, Negative tilt keyboard Tray:
- Can provide easy height and angle adjustability to facilitate neutral
posture typing and reduce reach distances to keyboard and mouse.
- Should only allow for downward sloping platform adjustment (negative
- Space efficient - slides beneath existing furniture.
- Allows for easy adjustment of keyboard to screen distance without the
need to move the screen.
- Inexpensive and retrofits to most workstation furniture.
- Should accommodate a position adjustable mouse platform that places the
mouse at or over the keytops.
- Eliminates shoulder abduction for right-handed mouse users with the
mouse positioned as in #6 above.
- Easy to remove to reinstall so can follow the employee.
- Incorporates padded palm support.
- Can provide user with visual feedback on slope angle for optimum
- May not retrofit to every worksurface design
- Poorly designed keyboard trays may not be stable and may bounce which
can disrupt typing.
- Poorly designed keyboard trays may restrict leg clearance.
- Some keyboard tray designs allow for an upward incline support surface
for the keyboard (positive angle) which can increase wrist extension
depending of tray height relative to the user.
Padded Arm-support worksurfaces:
- Provides arm support when typing and/or mousing.
- Can be retrofitted to existing worksurfaces
- May compress the finger flexor muscles in the forearm (see above image)
- Does not address issues of arm abduction
- May restrict free movement of the arms/hands when typing/mousing
- Increases reach distances to keyboard and mouse
If you have any questions or comments about the information on this page
or this web site you can send these to Professor
Alan Hedge at Cornell University.
Check out the details of arranging a computer
workstation for an adult and ergotips to
troubleshoot any symptoms that might indicate a poorly designed workstation
For more detailed information and exercises you can also check out the free 'HealthyComputing.com'
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Note that all materials on this page and web site are
copyright and may only be copied or distributed for nonprofit educational
purposes without permission.
© Alan Hedge, page content last revised on
March 02, 2008