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."

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.