Wayne Boozer on cross training and stamina:

I got into a discussion about this very subject with my instructor once. We were actually talking about a “secret” that he let me in on when I was testing for Dan; and I’ll share that same information with you. It’s more important to the testing board to see who finishes strong than who has the best kicks, the highest jumps, and the loudest yell. Pay close attention to the participants of a black belt promotional and recertification test. While everyone starts strong, remember the faces when you get to the end. Who has energy to spare? To me, that’s the sign of an experienced student.

Being able to control your breathing and relax properly is important to efficient use and conservation of your strength and energy, but that energy has to come from somewhere. Why do you think sport fighters do so much roadwork?  Cardio isn’t just good for your heart and your waistline.  How can you show that you’ve learned everything you’ve been taught if you’re gasping like a fish?