They are scared of their own shadows, ready to bolt over the horizon at the snap of a twig, tick of an arrow falling off its rest or brush of a boot heel against dry bark. Or any of 1,000 other things that, in our ears, barely make a sound at all. Getting the upper hand on such nervous animals, a prerequisite to getting any shot at all, can be accomplished in one of two ways. Other bowhunters tell me they can remain absolutely motionless on stand, save for the blinking of their eyes, for hours on end. I don't believe them, because I have tried and never lasted more than a few minutes without some sort of nervous twitch or involuntary spasm.
Body parts begin to ache.
The ones that don't ache start to go numb. Recovery demands at least a minor shuffle of the feet or twist of the torso, neither of which is disastrous to a bow hunt if the timing is right. More important than learning how not to move for bowhunters is learning when to move. Once deer slip within 50 yards, you must minimize and time your readjustments. If you can see a deer's eye, it can see you.