The thing is, Slim Jim, such shitting contests as you describe, take place before every event. Almost all athletes get the 'pre-competition' shits and spend a lot of time cleaning out their bowels before the game, race or performance. Hell, as a major college sports fan, I spend a lot of time on the pot myself before a big game. It's the body's way of allowing you to focus on the competition, itself, (or watching it) and not be distracted by the process of digestion. Thus--dump time.
As a former sportswriter and broadcaster, I remember one amusing but true comment from a fellow writer. He said: "I've been covering football for about twenty years now, and the one thing no one ever talks about is the amount of time the team spends on the toilets in the hours leading up to the game. The players and coaches may not always win the game, but they are rarely full of shit."