50 Fittest Female Athlete in the World with Bonus (Instagram)

36. Kristin Armstrong / CYCLING

Emma Pooley in the Elite womens time trial championships

A two-time Olympic gold medalist and three-time world champion in cycling, Armstrong has also previously been a long-distance runner, triathlete and swimmer. She took time off from the sport to raise her son and to recover from her multiple surgeries but returned, and now, at 42-years-old, Armstrong is trying to win her third straight Olympic time trial gold medal in Rio in August.