4.1 Workstation Set-up
Proper workstation set-up is an integral part of preventing work-related musculoskeletal disorders (WMSDs). In addition to the information below, contact EH&S for information on ergonomics, including online ergonomics training, and ergonomics product information.
The key to a proper and comfortable workstation is keeping your body neutral, relaxed, and supported. Neutral posture maintains a neutral, relaxed, and supported body position as follows:
- Neutral: Keep the head level, and the wrists straight.
- Relaxed: Keep the shoulders relaxed, and the elbows at the side.
- Supported: Keep the feet and the lower back supported. All ergonomic work practices and equipment should allow for this neutral posture at the computer workstation.
4.1.2 Work Surface
The following guidelines for work surfaces should be observed:
- Work surface should be large enough to accommodate all computer equipment (approximately 30 inches deep).
- There should be adequate viewing distance between user and monitor (16-30 inches).
- A height-adjustable keyboard tray can be used to increase depth and provide proper keyboarding height.
- There should be enough legroom under the work surface for leg movement (28 inches wide).
The following guidelines for adjusting your chair should be observed:
- Chair height: Sitting with your hips all the way back and your back resting against the backrest, adjust the height of your chair so your feet are resting flat on the floor and your thighs are parallel to the seat with the knees bent at an approximately 90º angle. Make sure your knees are not higher than your hips. If your feet do not reach the floor, you may need a footrest; if you are tall, you may need a chair with a taller stem.
- Seat pan depth: Sit with your hips all the way back in your chair, and your back against the backrest. Make sure there is space between the back of your knees and the front of your seat pan. Most chairs have a sliding seat pan. Adjust the depth of the seat pan so there are one to two inches between the front of the chair edge and the back of your knees. If there is no space between the back of your knees and the chair edge, you may need a different chair with a smaller seat pan.
- Lumbar (lower back) support height: Raise or lower the backrest so your lumbar area is fully supported.
- Chair armrests: If your chair has armrests, they should allow you to get close to your work without getting in the way. When you type they should be at a height so that they barely contact your elbows when your arms are resting comfortably at your side. The chair armrests should not force you to elevate your shoulders or "wing" your arms out to the side. If you cannot adjust your chair armrests to the right height, or they keep you from getting close to your work, remove the armrests.
The following guidelines for keyboards should be observed:
- Keyboard tray height: With your arms resting comfortably at your side, the home row of your keyboard (the row with letters a, s, d . . . ) should be just elbow level. If your work surface is too high and cannot be adjusted, adjust your chair to bring your elbows to the home row level of the keyboard; support your feet with a footrest if necessary. You may be tall enough so that you can keep your keyboard on your desktop. If you are so tall that the keyboard on the desktop is too low, you may need to raise your desk.
- Keyboard tilt: In the ideal typing posture, both static and dynamic muscle loads are minimized. This posture is achieved when the keyboard is below elbow height and the keyboard base is gently sloped away from the user so that the key tops are accessible to the hands in a neutral posture. In this position the arms, shoulders, neck and back can relax, especially during brief rest pauses. Try tilting your keyboard tray away from you. (See Figure VIII.2.) You might prefer using a trackball with this configuration, as the mouse sliding off the keyboard tray is likely to frustrate you.
Figure VIII.2: Maintain the Ideal Typing Position while at Your Keyboard