Besides body positioning, it's also important to have the right mindset. I've read in many motorcycle rags (Sportrider, Lowrider, Easyrider, *your name here*rider) that the best racers run the course in their head, cogitating through the course. Some scientists call it mental imaging. The Blue Angel pilots do it too (I watch way too much History Channel). I find this pic encompasses both the physical perfection of body positioning, and the intense focus of the subject as he mentally maps his way through Tokigi.
Or constipation.