July 27 marks the kickoff of the 2012 London Olympics, but Team USA's athletes have been prepping for years. Whether it's a comeback that has been warranted since 2008's Beijing Games or a rookie getting his or her first chance, it's no secret that this year's Summer Olympics are going to be action packed.

Take for example swimmer Ryan Lochte, who has been on eight-time gold medalist Michael Phelps' tail for years. But don't expect Lochte, 27, to be taking the back seat this time around. "I think overall, I'm just a lot older, smarter, and a better athlete than I was going into Beijing," the 6-foot-2 athlete, who swam four events at the Games and took home two gold (one earned as a group) and two bronze in China, tells Us Weekly. "I changed my diet and I started doing heavier weight lifting."

Another name to watch out for is up-and-comer gymnast Gabby Douglas, who makes her Olympic debut this year at age 16. But it was only two years ago that her gymnastics career really took off. In 2010, the teen moved from her hometown of Virginia Beach, VA to West Des Moines, IA, where she has been training with champion coach Liang Chow ever since. (Chow trained 2008 Olympic gold medalist and Dancing with the Stars contestant, Shawn Johnson.)

"It was hard being away at first, but I'm stronger because of it!" she tells Us of her perseverance.

Want more Olympics? Meet Team USA's families, go inside their homes (and gyms!), and more!  Get to know gymnast Aly Raisman, champion tae kwon do siblings Steven and Diana Lopez, competitors-turned-volleyball teammates Jennifer Kessy and April Ross and more. Check out Us Weekly's Olympic collectors edition, "American Heroes," on newsstands now. Order at bn.com/usolympics.