To me, it doesn't feel like sprinting. I suppose to the cheetah, it doesn't feel like sprinting, either... just normal running. Then the cheetah wonders at the plodding pace of the lion.
What I was meaning by sprinting... is I have a mode A and a mode B. Mode A, I can do all day long. In mode B, I am running at a few SDs higher in IQ, can finish four hours work in an hour. But when I hit a wall I'm done/shot for the rest of the day, mentally exhausted. While "sprinting," I'm likely to be twitchy, rock in place, tap, be very short, inattentive, no sense of time.
