AKB4000008: Ergonomics for your desktop computer
By @CanadianTech
Published 6 Feb 2017 rev 1.0
Your body has a range of positions and movements that are natural to it. Working outside your range may cause injury, especially if you hold a position for an extended period or continuously repeat a movement. The following steps will help you to take better care of yourself.
Place your keyboard directly in front of your monitor, and sit directly in front, without twisting your neck or body. With your hands on the keyboard and wrists straight, adjust the height of your chair so your arms are bent in a square “L”, with your forearms parallel to the floor. Your feet should be flat on the floor with your legs at near-perpendicular angle, while not putting pressure on your thighs. If this is not the case, lower or raise the keyboard, if you can, or use a foot rest. (A thick telephone book can make a great foot rest.)
Tilting your keyboard up from the back is likely to cause you to bend your wrists. If the legs on the underside of your keyboard are extended, you may need to retract them. A wrist-rest may help you keep your wrists straight.
If your monitor is on top of your computer, it is probably too high. Adjust the height of your monitor so an imaginary line drawn from the bridge of your nose to the centre of the screen is about 15° below horizontal. If you wear multi-vision lenses (bifocals), the angle should be about 20°. You may wish to consider asking your optometrist for special glasses. You may also have to raise or lower your chair to achieve these angles. If necessary, move your computer (not the monitor) to the side or under your desk, either flat or on its side. Make sure to turn everything off before moving it and be careful of the wires that connect everything. Longer cables are available.
Your monitor’s screen should be 15 to 24 inches (38 to 61 cm) from your eyes. Adjust the position and angle to minimize reflections from electric and natural lighting. Use an anti-glare cover only if necessary.
Adjust the brightness and contrast of your monitor by following these steps:
- Adjust the brightness so that it is too dim to see.
- Gradually brighten until you can comfortably see what is displayed.
- Adjust contrast to your comfort. This may necessitate adjusting brightness again.
If you use a mouse, it should be at the same height as your keyboard and beside it on the right or left side. Use a mouse pad that is made for that purpose. If you are left-handed, use the mouse with your left hand. If you are right-handed, use the mouse with your right hand.
Switch your computer’s software to left or right-handed operation so that the first or primary button is under your index finger. Also, as you gain skill in using your mouse you should increase its speed (sensitivity) to reduce your hand movement.
Change left or right-handed operation by doing the following: Click on Start, Control Panel, Printers and Other hardware, Mouse. You should find the way to switch in this window. The precise steps will vary depending on software versions. To increase speed, click on Pointer options. You can also change the double click speed and the size and colour of your mouse pointer in this dialogue window too.
Rest your hand on your mouse and relax. Don’t grip or squeeze it. Use your entire arm to move it. Don’t bend your wrist. Don’t bend your fingers to press the buttons.
If you use your computer to transcribe from documents, place them beside the monitor. If you do this often, use a copy holder that will position the papers at the same height, distance and angle as the face of your monitor.
Each 20 – 30 minutes, take a 30 second break Rest your eyes. Focus on something 20 feet or more away. Move your body, particularly your hands, arms, shoulders, neck and back. Your back loves to move, and will appreciate these short, but important breaks.
