Sarah Groff, United States. Age at the Olympics: 30
Sarah Groff became the first American to ever get on the overall podium for the World Triathlon Series when she won bronze last year by racing consistently throughout the entire season, including getting on the podium at the Kitzbühel, Austria, leg of the World Triathlon Series (another first for an American women.) But what’s scary about Groff is despite her career-best results in 2011, she wasn’t in the best shape of her life in 2011, thanks to a twice-broken sacrum that disrupted her winter training. Instead of racing well on fitness, she got by on improved technique and racing strategies courtesy of her longtime coach, Darren Smith. Now that Groff has had a consistent preseason of training under her belt, it’s possible that she’ll have another breakthrough season—and get on the podium in London. She’s a great swim-biker, as well, which means if there’s a break in London she’ll be sure to be a part of it.