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The
Logitech trackball put an end to the soreness I was developing in my wrist and hand.
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QFT, i switched to one of these and have had no issues since. Get a microsoft egronomic keyboard (the split ones) to help your wrists some more. You may even swing work to pay for them at your office, RMI is a safety injury for them.
THe general rules of thumbs i remember are to have your forearms parallel to the ground, and to not have your wrists cocked when typing/mousing.