U.S. five-time Olympic swimming champion Aaron Peirsol, who still owns world records in the 100m and 200m backstroke, has retired from swimming competition.

Peirsol confirmed his retirement to the Austin American-Statesman, his hometown newspaper in Texas, that he will not compete at next year's London Olympics.

"Retiring is such a strange word. I'm 27 years old. I've still got stuff to do," Peirsol told the newspaper. "But to do this right, you have got to give it 110 percent. I can't give it 110 percent any more."

Aaron Peirsol of the U.S. reacts to setting a new world record in the men's 100m backstroke final at the USA Swimming National Championships in Indianapolis, Indiana July 8, 2009.

Peirsol has applied for political science graduate studies at the University of Texas, where he was a collegiate swim star.

Peirsol won three gold medals at the 2004 Athens Olympics and took the 100 backstroke gold at Beijing as well as a relay gold, but struggled when it came time to prepare for London.

"It was hard for me to reset, to find something worth going for the next year," he said.