They have to mine the muscle memories or else they could leave us out entirely from the battlefields. The players' physical responses are only relevant insofar as their hand-eye coordination. The animation, the realness, comes from my own live-action experiences and instincts. I have to be at least partly paying attention for my own physical responses --even stomach acids are measured-- to kick in. At least the K's always win. I'd hate to experience death again.
Some of the players I recall this guy Ken who viscera really seemed to match mine maybe from his generations of farming. He was shy to fight and almost made me switch into mate mode by wandering back toward the cliffs, some of the abandoned ones, when there were plenty of flakes to scoop up and showing off to do with simple evasions of their little sling-shot stones.