A Primer in Office Ergonomics
The following Primer of Office Ergonomics, provides a bulleted checklist of the major considerations for a computer workstation setup. This is not intended to replace a professional ergonomic assessment of your workstation or work process, especially if you are currently dealing with pain or injury.
Should you have specific questions, please contact:
Wayne Albert, PhD CK
WHAT IS ERGONOMICS?
Ergonomics is the science of studying people at work and then designing tasks, jobs, information, tools, equipment, facilities and the working environment so people can be safe and healthy, effective, productive and comfortable (Ergonomic Design Guidelines, Auburn Engineering, Inc, 1998).
STANDARD DESK HEIGHT
- The standard desk height is 30-inches and cannot serve the 5'2" employee and the 6'2" worker equally.
- For a 5'2" employee, the appropriate desk height would be 24-inches, six inches lower than the standard desk height of 30-inches
- A rule of thumb is to add one-inch of desk with every three addition to employee height. For example, a 6-feet tall individual should work at a desk height of 27" high
- If the purchase of a new desk is not financially viable, an option may be to cut the desk down to 24" and adjust it for various employees using 1-inch blocks
- An L-shape configuration is ideal, where space permits, as it provides a large area for the computer workstation within the corner of the L, and the two arms of the L can then be used as functional space for writing or peripheral devices (printers, scanners, telephones, standing file folders.
- For many work areas where the proper desk height is not an option, the chair becomes the most critical component of the work station as it supports the arms, legs and back
- Sitting is a dynamic activity and it is critical that the chair be adjustable allowing the back to rest comfortably on the back support and the arms comfortably on the armrests
- When seated, you should not feel any pressure at the back of knees. In fact, there should be sufficient space to place a fist between the edge of the seat and the back of the knees
- The armrests should not permit the chair from being pulled up to the workstation. If it does, you will not sit with relaxed shoulders (thus placing increased strained on the neck and shoulder muscles). The rate of arm and shoulder fatigue increases dramatically when the arms are unsupported or raised even slightly.
- The chair width should be such that when sitting and typing the arms are support at the elbow and part of the forearm
The workstation setup must permit you to keyboard and mouse with:
- Head upright and over your shoulders.
- Eyes looking slightly downwards (30°) without bending from the neck
- Elbows bent at 90°, forearms horizontal. Shoulders should be relaxed, but not depressed.
- Wrist in a neutral posture (straight): the wrists and fingers should maintain a ‘waterfall' shape (hold your forearms parallel to the ground and let your hands relax, they will assume a waterfall shape)
- Back should be supported by the backrest of the chair which will promote the natural curve of the low back.
- Highs horizontal with a 90°-110° angle at the hip
- Feet fully supported and flat on the floor. If this isn't possible, then the feet should be fully supported by a footrest
- The mouse should be at the same level as the top keys of the keyboard
- You are encouraged to mouse with their non-dominate hand, change mousing hands periodically (weekly, monthly). For example, have your mouse arranged for right-hand use at home and left hand use at work, thus sharing the strain and providing adequate relief (rest) from constant mousing.
- Your wrists should rest on a comfortable surface while mousing/keyboarding to avoid damaging or impinging a nerve that runs close to the surface at the wrist
- The computer monitor should be placed an arm length away at minimum
- The monitor should be slightly below eye level and tilted back at an angle of 10 to 15 degrees - this provides the least neck strain and best accommodation for the eyes (bifocal wearers may need to adjust the height and angle of the monitor to accommodate for the portion of the glasses from which they read)
- Placing the workstation so that a window is directly in front or behind the monitor will result in glare from the sunlight either in the your eyes or on the screen, respectively
Lighting is a major concern in most office environments. Fluorescent lighting has a flicker that is very irritating to the eyes and is a major cause of headaches. My recommendation is always to avoid using the fluorescent lighting and replace it with halogen lighting (a stand up lamp or two for general office lighting). To supplement the general lighting, a task lamp should be placed on the desk to provide direct lighting to documents being worked on. Naturally visual impairments must be taken into consideration.
GIVE YOUR MUSCLES A BREAK
When working at a computer workstation, a 5-minute mini break for stretching and muscle relaxation is recommended after each hour of work:
- Try to change body positions occasionally, stand up and move around to change the muscles being used
- Take your regularly scheduled breaks and lunch break away from your desk, again to provide a change in posture and muscle usage
- Give your eyes a break as well - use the 20-20-20 rule: Every 20 minutes, look 20 ft away, for 20 seconds. This will allow your eyes to accommodate to a distance further than an arm length away at your monitor