You can get away with some fairly bad form (really bent arm, twisted around in a treestand, awkward angles, etc...) and still be able to hit the boiler room pieplate consistently out to 30 yds. But doing those same things will not allow you to be competitive in a target archery venue where you have to hit a little bullseye 60 or 90 times in a row to be in the top group of archers.

When I said muscles are not very consistent and are much more prone to fatigue and form deterioration over time, I maybe should have said "over a shooting session". With fresh muscles making only one shot, you can get away with a little more latitude on form vs. shooting a 100+ arrow target tourney.