I played football in high school (Muncie Central) and it was a requirement that the football players take Physical Conditioning classes and I just stuck with it.

You know that feeling after you have just gone super hard on leg day and you start walking and it feels like you're about to stomp pot holes in the ground with every step? Or how about when you are walking and you can feel all the muscles movements? The feeling of POWER the you posses, like you could carry the earth on your shoulders.