I agree with everyone who has already posted. To many layers, the cold it's self, getting stiff from sitting, and drawing to much weight. I had this happen to me once. Dropped my draw weight 5lbs. Never happened again. I keep my draw weight at 65lbs. now but i know guys that crank it up when it's warm and turn it down when it's cold. By the way I'm 6'2" 230 not a strength problem, I know.