If you wear bifocal glasses, be careful of your head and neck posture when you are using the computer. Because the bottom half of your glasses are used for reading, you must tilt your head up to read the computer screen. This places pressure on your neck musculature and can result in pain and discomfort. If possible, use the computer without wearing your glasses or consult your optometrist about getting computer-specific glasses.
It is important to keep your elbows at 90 degrees when keyboarding. If your keyboard is too high, your shoulders will hunch up to reach the keyboard. This causes strain and tension in your trapezius muscle (large diamond-shaped muscle that connects the top of the neck and the vertebrae to the collarbone and shoulder blade). Ideally a keyboard and mouse tray should be used to achieve the correct height, or as a secondary measure, you can raise your chair height and use a footrest (or a phone book or two) so that your legs don’t dangle.
A general rule of thumb for viewing distance from your computer monitor has been “an arms’ length” away. However, with newer screens becoming bigger, this may not always be the case. There has been no definitive research on this topic recently so my recommendations have leaned towards “whatever feels comfortable”. Keep in mind: If you are too close to the monitor, there is the possibility of eye strain and fatigue. Also, head and neck motion increases to see all parts of the screen, especially with the super-size screens (over 24”). If you are too far from the monitor, you will tend to lean into it because the font will be too small to be able to read comfortably. This will place unwanted pressure on your neck and upper back. My advice would be to sit where your eyes feel most comfortable, make sure your head and neck are upright, and adjust the font on the screen if it’s too small.
When sitting in your chair, there should be 1” of space between the back of your knees and the edge of the seat pan. If there is more than 1” of space, your legs may not be getting the support they need resulting in fatigue. If there is less than 1” of space, the seat pan will put pressure on the back of your knee causing discomfort and possibly numbness. Also, this discomfort will likely cause you to move forward in your chair and stop using the backrest, causing additional fatigue and discomfort in your back. Find a chair that fits your legs – a chair that has a “seat pan depth” adjustment is ideal.
Adjust the backrest of your office chair so that the lumbar support rests in the curve of your low back (about where your belt line is). Support is needed in that spot so that your vertebrae stack properly on top of each other. When you are standing your back maintains a natural curve, but when you sit down this curve flattens out and places extra and non-uniform pressure on the intervertebral discs. This pressure places stress on the soft tissues of the back and may result in discomfort and possibly injury. If you do not have lumbar support in your backrest, a small folded towel will also work.
If you perform the same task over and over throughout the course of the day, using the same muscles, tendons, and ligaments; you are at risk for injury due to repetitive motion. Human bodies are not meant to perform tasks without variety in movement. Soft tissues such as muscles, nerves, and connective tissue become fatigued and blood supply is restricted when there is repetitive motion. To assess whether your movements are repetitive at work, keep a log of your tasks throughout the day. For example, if you start typing a report, make a note of what time you started and when you finished. Make a note of any rest breaks or other diversions, e.g. a phone call. If you type more than one hour without a break, you are placing yourself at risk for injury due to repetition. Try to make sure you break up your tasks during the day with other non-similar tasks or with 1-2 minute rest breaks. You should actually find yourself being more productive and less fatigued when you give your body time to repair and rejuvenate.
When using the computer, keep your chin down and your neck and upper back straight. Many people tend to lean into the computer screen with their head which causes strain to the muscles of the neck and upper back.