Former 100m world record holder bows out after battle with injuries takes its toll.
Maurice Greene, the Olympic 100m champion in 2000 and former world record holder in the event, announced his retirement on Monday citing recurring injuries that have dogged his career in recent years.
"Injuries are every sprinter's worst nightmare, and I seem to have been constantly fighting them for the past three seasons", the 33-year-old known as the 'Kansas Comet' said on the Internet site of his agent.
"So I have decided to retire from competing in the sport which I love and which has given me so much over this past decade".
Greene was Olympic champion in 2000 and a three-time world champion in 1997, 1999, and 2001. But since winning bronze at the 2004 Olympics in Athens, he has had a series of injuries hampering his career.
The veteran made the announcement in Beijing on a pre-Olympic visit with a group of world and Olympic champion athletes, including compatriot Tyson Gay, the 100m and 200m men's world chanpion.
Greene said he was sorry he would not be competing in the Beijing Olympic Games but felt confident that a new generation of US runners such Gay would guarantee continued success for the US team.
"I am going to always wish I was going to run here in Beijing," he said. "But I believe Tyson is capable of taking my spot and to bring the gold medals back for the United States".
He said his future probably lay in coaching.
"I have been coaching some athletes and you know, just trying to help them achieve great things," he said. "It's something I like".
Greene, who is based in Los Angeles, said he would consider coaching Chinese sprinters in the future.
China's has produced only one men's track star, 110m hurler Liu Xiang, who is world and Olympic champion and also holds the world record.
"We in America have been doing the sprints for so long, we know what works", he said. "If we had someone over here to help the Chinese train, I think they could compete just as well".
USA Track and Field president Bill Roe hailed Greene for transcending track to become a fan favorite.
"Maurice has secured his place as one of the greatest sprinters and greatest champions in track history. He set the standard for a generation of sprinters and put his own stamp on events with his audience-friendly personality". he said.