I don’t like keyboard wrist supports, those long slips of fancy-padded rubber that sit directly in front of keyboard trays. Here is why.
The ideal position for your wrists and fingers to work in while typing should be “neutral,” neither flexed nor extended. This is best done with the wrists hovering ever so slightly above the keyboard. The fingers are able track slightly downward and find their way to the necessary keys. A keyboard tray will usually make the neutral position of the wrists easy to maintain.
In contrast, wrist supports force the user to plant his or her wrists in front of the keyboard while striking keys. If you look at both the fingers and the wrists during this activity, they are both forced into a good deal of extension. The person typing must lift each finger quite a bit to get from key to key. Although this may seem innocuous, the cumulative effect of lifting the fingers repetitively and keeping the wrists in slight extension for hours at a time can be devastating. Many people will develop strain in the forearm as the extensors become chronically overused.
I see many patients who have tennis elbow and wrist tendonitis directly caused by the faulty keyboard ergonomics described above. The overworked extensor muscles of the wrist and fingers originate at the elbow. Pain and strain can therefore manifest anywhere from the lateral aspect of the elbow all the way down to the top of the hand. In these cases, all of the medical intervention in the world will not permanently get rid of symptoms until the positions of the wrists and fingers are changed with typing.
If you have a rubber wrist guard, use it to rest your wrists while you are NOT typing. Better yet, throw it out and use a keyboard tray. Keep your wrists floating above the keyboard and type downward onto the keys.