Cornell University Ergonomics Web

Some Ergonomic Considerations when Designing a Computer Workstation

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:

 

Some Advantages:

  1. Integrated into workstation furniture design.
  2. Not retrofittable.

Some Disadvantages:

  1. 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 mouse.
  2.  If the surface is angled down the mouse runs off (a trackball can work here).
  3. 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)
  4. You lose primary desk real estate in front of the person (for documents etc.)
  5. You no longer have a uniform flat desk worksurface.
  6. 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.
  7. Height and angle adjustment mechanisms can be are coupled in some way and may not easy to use.
  8. There's usually no user feedback (i.e. numerical indicator) on the slope angle of the surface.
  9. No palm support \to facilitate neutral wrist posture.
  10. 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:

Negative-tilt keyboard tray can facilitate a neutral seated-body posture.

 
Negative-tilt keyboard tray can facilitate a neutral wrist posture.
Articulating mouse platform can facilitate a neutral wrist and arm posture.

Some Advantages:

  1. Can provide easy height and angle adjustability to facilitate neutral posture typing and reduce reach distances to keyboard and mouse.
  2. Should only allow for downward sloping platform adjustment (negative tilt)
  3. Space efficient - slides beneath existing furniture.
  4. Allows for easy adjustment of keyboard to screen distance without the need to move the screen.
  5. Inexpensive and retrofits to most workstation furniture.
  6. Should accommodate a position adjustable mouse platform that places the mouse at or over the keytops.
  7. Eliminates shoulder abduction for right-handed mouse users with the mouse positioned as in #6 above.
  8. Easy to remove to reinstall so can follow the employee.
  9. Incorporates padded palm support.
  10. Can provide user with visual feedback on slope angle for optimum positioning.

Some Disadvantages:

  1. May not retrofit to every worksurface design
  2. Poorly designed keyboard trays may not be stable and may bounce which can disrupt typing.
  3. Poorly designed keyboard trays may restrict leg clearance.
  4. 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:

Some Advantages:

  1. Provides arm support when typing and/or mousing.
  2. Can be retrofitted to existing worksurfaces

Some Disadvantages:

  1. May compress the finger flexor muscles in the forearm (see above image)
  2. Does not address issues of arm abduction
  3. May restrict free movement of the arms/hands when typing/mousing
  4. 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 arrangement.

For more detailed information and exercises you can also check out the free 'HealthyComputing.com' web site.

Happy computing!

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© Alan Hedge, page content last revised on March 02, 2008