A large proportion of the American public goes to work every day in an office environment without considering the ergonomics of the equipment they use. There are large a proportion of people working at a desk without giving due consideration to proper ergonomics as they work with ergonomically incorrect keyboards and mice. Working at a computer on a regular basis can cause the same type of stress on your body as other physical labors and in an effort to prevent such injuries from occurring, companies need to consider the principles of ergonomics.
via Ergonomically Correct Mice and Keyboards: the Many Benefits.