Age: 25 In 2005, it looked like Aaron Gwin's short, bright career in motocross was over. He was only 17, but nagging injuries from motocross and, before that, BMX riding, forced him to give up his sport. Three years later, though, a friend and professional downhill racer loaned him a bike and encouraged him to enter a race. In his very first competition, he took third place. Pretty soon, he signed on with Yeti Cycles and started rising through the ranks of downhill racers, aided by the skills he'd gained from his early BMX days. That year, he took the Mountain States Cup Championship Series by storm, garnering four first-place finishes, as well as taking eighth place in the UCI Mountain Bike World Cup. In the past two seasons, the man is nearly bulletproof, dominating at the World Cup level and setting a new record for most victories in a single season (five). Two months ago, he left Trek World Racing to ride with Specialized, and the mountain bike world will be watching this spring as he tears down the mountainsides of the world, try furiously to ride his way into the record books. —Kurt Miller For more on Aaron Gwin, click here.