"I like to say the most important muscle we have is the six inches between our ears, our mind," he says. "You actually have to do the reps on the mental bench press." The 12-hour walk itself is obviously a very deep, immersive practice of saying, Hey, now I'm not fit enough to do the rock'n roll workout you just told me about. But it's also holding up a mirror where you are going to go deep into yourself and see how far you can push your body.