To Mnny and all other desk jockeys, or anyone that spends alot of time at th computer... probably a good portion of us.
In the past one of the jobs I used to do was to help with the building and testing of fiberoptic filters. Eight hours on my feet in a sterile white room with flourecent lights, hard floors, 1mm cubes of coated glass, and all sorts of technical tools and chemicals to help us do our job.
I was on the ergonomics team, the lead for the graveyard shift, and we met weekly to discuss how to make the lab a "safer" place for us to work, as well as how to avoid RMI's (repative motion injuries) and other work-related injuries. Because we were on our feet all day we had the company invest in shock-absorbing matts to put infront of each station. The desks also adjusted so that you could adjust the table height up or down as needed. We also had monitor risers, gel wrist-rests for all the mice, and took regular stretch breaks with a 5 minute series of stretches we could do to help with low back, neck, arms and legs.
You should, by law, be permitted two breaks during the day aside from lunch; utalize these to stretch! Make sure your desk chair adjusts and put it at the correct height in correlation with where you arms land on the desk for the keyboard. If you do not have an ergo-keyboard they do make the gel wrist-strips for infront of them, along with the matching mouse pads. If your monitor is on your desk, and your desk is one level surface, please, /please/, raise your monitor to the proper heigth! I can not stress how important this is to your neck. Don't have monitor risers? Phone books work wonders! You will remove alot of neck, shoulder, and even eye strain by having your monitor in the proper position. Posture also plays a key point when sitting for long periods of time; it's hard to not slouch when sitting and typing alot, but try to make a concious effort to keep your shoulders rolled back. At home you can wear one of those posture-harness devices until muscle memory sets in to help you keep your sholders in place. A foot rest is also a good investment, but with a proper chair, and the proper height plus the stretching, it's not as critical. Also, if you can do it, do little exercises with your feet through out the day; this generally does not interfer with work production, typing, or anything else. Just don't accidentally play footsie with a co-worker.
That's about all I remember, that and all the stuff we had to know about how to adjust our bodies to go against our natural biorythem given I worked on the grave shift, but with my knowledge of bio-mechanics of the human body, muscles and skeleton system (I am a certified massage therapist, though my condition no longer permits me to practise) I was a prime candidate for the ergo leader position. To many offices have gotten away from this practise, and more often then not we're not as aware of these things in our home as we are at work.