100 Olympic Athletes To Watch

41. Aaron Peirsol

Swimming
United States
Age: 23

For seven years, Peirsol ruled the 200m backstroke. Until, that is, teammate Ryan Lochte beat him to the wall at the world championships in the 200m race last year. Peirsol tied that time at the Olympic qualifiers last month, but given his penchant for world records, he'll likely stroke past it in Beijing. An avid surfer and environmentalist, Peirsol recently built a house in Costa Rica, and is an advocate for preserving the oceans.