Gold medal-winning gymnast Nastia Liukin will make her debut as an Olympic gymnastics commentator at the 2016 Games in Rio this summer. "This is a huge deal! I'm so excited to be back," Liukin, 26, tells People. "I've been keeping track of all the gymnasts in the competitions leading up. I've gotten to know the gymnasts, their start values and their routines." She adds, "it's a little challenging, though, because when I'm commentating I have to remain neutral and I'm still friends with these girls, so that's hard for me!" The five-time Olympic medalist and two-time all-around national champion will join former Olympian Tim Daggett,...