>> glassman: yes. yeah. logan: crossfit classes usually don't take more than an hour. athletes compete against each other and the clock. >> good job. to keep their energy up, they're encouraged to follow something called a paleo diet, heavy on meat and vegetables-- food fit for a caveman. i have heard you say that crossfit prepares athletes for "the unknown and the unforeseen." >> glassman: it's the... >> alfonsi: it sounds like you're getting ready to go to war. >> glassman: yeah, why not? yeah. for getting ready for war, getting ready for earthquake getting ready for mugging, getting ready for the horrible news that you have leukemia. what awaits us all is... is challenge, that's for sure. >> alfonsi: crossfit, he says, is creating a new "super breed," and although some of their athletes appear to be carved out of marble, he says the focus isn't big muscles. it's simple, functional movements like squatting and lifting, whether you're 25 or 75. >> glassman: would i use dead lifts in both cases? absolutely.