What to look for in Keyboards and Keyboard Trays
Avoiding Repetitive Stress
The first solution for avoiding repetitive stress is to take a 'microbreak', sixty seconds of mild stretching and flexing every twenty minutes.But twenty minutes from when?
For jobs, which focus on data entry or writing, measuring twenty minutes may be done with a kitchen timer. But for the rest of us, it can be a moving target. Break times can be cued by software products, which count keystrokes and mouse movements, as well as time, to determine that a stretch break is due. These products usually include examples of stretches. Naturally occurring interruptions, such as phone calls, can serve as a opportunities to take a stretch break.
Two things to keep in mind when mousing are: one, there is not a need to keep in constant touch with the mouse, and two, you can break up the repetition of constant mousing by alternating hands.
Neutral Posture
If you were to raise your forearms forward from your waist, your wrists and hands would be in their neutral posture. This neutral posture is an unlikely typing/mousing position for most of us
For most of us, the common desk height of 29" does not provide the possibility of a neutral position. Shoulders are flexed up to raise our forearms to typing height, pinching nerves in our neck and shoulders.Our forearms may be resting on the edge of the desk, causing pain from the sharp edge on the forearm. Wrist rests are generally below the plane of the straight wrists; often the wrists are bent down so that they can rest on the cushion. Flexing the wrist this way can actually aggravate tendons, nerves, and blood vessels in the forearm causing carpal tunnel syndrome, tendonitis, and similar painful conditions.
There are a number of accommodations that we can make for a more neutral typing and mousing position. Starting at the top, our shoulders should be relaxed. Elbows should describe a 90-degree angle and be close to our side. The wrists should be straight from the elbow to the fingertips.
For most of us, a typing/mousing height of less than 29" is the preferred or more neutral position. (Remember, typing returns? They were 26" high.) An adjustable keyboard tray allows us to make an adjustment to a height, which will allow us to relax our shoulders and maintain a neutral typing/ mousing posture. A good adjustable keyboard tray accommodates the keyboard and mouse and provides for easy vertical adjustment, angle adjustment, and can easily be slid under the worksurface when not in use.
For taller individuals, a keyboard tray that allows for adjustment above the worksurface may be needed to achieve the proper height for neutral shoulder and forearm postures.
Ergonomic keyboards reduce the lateral flexion in our wrists. A conventional keyboard causes us to "toe" our wrist together; stressing the forearms. Ergonomic keyboards may take some getting used to, but they're usually worth the effort. Some ergonomic keyboards allow the user to adjust the horizontal split and vertical angle of the keyboard. This provides a way to get used to a more neutral posture a little at a time.
There are several different types of devices for "mousing". In our experience the success of a given "mousing device" varies among individuals. Keeping in mind the goal of having a neutral posture, the wrist should be relaxed and unflexed. Experimenting with different sizes and shapes of trackballs, touchpads, and mice may be necessary
.