Lifthrasil: Get a better chair. :-)
Smannesman: Or simply
a chair, he really shouldn't be sitting on his desk.
good catch, i think we have found your problem cmdr! :D
i actually started off raising my desk and alternating between sitting and standing, but when i play with a controller i slough / lay / prop myself up with cushions and that is my preferred way (takes an age to get the cushions right so im correctly supported ) but i still shuffle at times and sometimes even stand *shrugs*
honestly with a keyboard and mouse, its all about the correct height. do you remember when you learned to type / use a mouse it hurt like hell until you shifted your position? its the same thing - but it is usually k/b and mouse
height that is the problem. a lumber supporting rack thingy-ma-jig will help maintain correct posture and stop you slouching (as much - ive been known to slouch with one *shakes head*!