I highly doubt Matt Leinart was the first one to try ballet in order to improve his footwork and agility on the football field, but either way dancing and football just seem to go together like peanut butter and jelly.
When a player scores, the touchdown is usually followed by a touchdown dance. It’s only natural.
Hell, now football players break out into a dance after any kind of good play. Get a sack… do a dance. Pick off the quarterback… do a dance. Scare the crap out of Mark Sanchez when he’s lined up outside… do a dance — and laugh hysterically later.