June 29, 2002
Safer Keyboarding
by Dirk McCuistion
At first glance, typing on a keyboard seems safe enough. However, it is one the most common causes of forearm and wrist pain we see at MassageSpecialists. The individual pecking away at keys doesn't seem to have a big effect on your forearm. But when you spend hours a day at work or home typing and using a mouse, the impact on your forearms starts to add up. For example, let's say that you type approximately 40 words per minute, assume each word is five letters long. That means that you are doing about 200 keystrokes per minute. If you average the 45 minutes per hour on the computer at 4-5 hours per day that’s 45,000 keystrokes a day! Using a mouse may involve less individual finger movements but more wrist and index finger movements. The combined effect of all this work eventually adds up to tight forearms and may lead to pain, numbness and eventually carpal tunnel syndrome.
What to do:
Since most of us have to work on computers it may be impossible to minimize the time you spend on them. One key to staying healthy is efficient positioning. Traditional keyboards and the way many people use them, create problems with regards to efficient positioning. If you consider the neutral anatomical position for the hand and forearm (as seen in the picture below) all of the joints are in the middle of their movement range. Muscles are stronger and more efficient in this neutral position. A traditional keyboard sitting on your desk typically creates three problems that impact arm muscles. (Double click on the picture to the right to watch a video that illustrates these problems).
What to do at a glance:
- Use a keyboard tray for appropriate shoulder positioning.
- Tilt the front edge (the edge closest to the monitor) of the keyboard slightly down.
- Try a split keyboard to take the load off the muscles in your forearm.
 Ergonomic equipment such as a keyboard tray enables a user to adjust wrist extension, shoulder height and arm extension.
Additional problems occur when your keyboard is not at the appropriate height. A keyboard should be approximately two inches lower than your writing desk height. A keyboard that is too high or low will stress muscles of your shoulders as well as your wrists.
Tilt the leading edge of your keyboard down to minimize wrist extension. A good keyboard tray should allow you to adjust the tilt of the tray. This allows the tendons and nerves in the carpal tunnel to achieve the straightest line with the least friction.
New split keyboards combine with keyboard trays offer some more options to decrease the impact on your forarms. A split keyboard is useful because it allows a user to eliminate ulnar deviation, the un-natural movement of cocking your wrist toward the pinky side.
 Remember, the muscles in your forearm may be disproportionately small compared to other muscles in your body but they do a lot of work. Try to set yourself up this the most efficient position possible. Stretch daily and take frequent breaks to break up the stress of the day. If you start to have problems come see us at www.MassageSpecialists.com we specialize in treatment of repetitive strain injuries.
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