Nastia Liukin & Derek Hough Prepare for Their DWTS Samba Routine

YH is in the Big Apple to catch up with Olympic gymnast Nastia Liukin as she prepares for her "Dancing with the Stars" Samba routine with her pro partner, Derek Hough! The twosome share with us how they keep healthy and eat fresh during their respective grueling schedules, plus they reveal their keys to performance chemistry and their pre-show rituals!