U.S. sprinter Maurice Greene retires

BEIJING, Feb. 4 (UPI) -- U.S. sprinter Maurice Greene, a two-time Olympic gold medalist and former world record holder in the 100-meter dash, said he is retiring from track and field.

Greene, 33, of Kansas City, Kan., cited difficulties in working back from injuries in preparing for the 2008 Olympics in Beijing as the reason for his retirement, CNN International reported.

Greene won gold medals in the 100 and 400-meter relay in the 2000 Olympics in Sydney. In 1999 he was clocked in 9.79 seconds in the 100, setting a world record. That mark remains the second fastest ever run in the event.

He also won silver and bronze Olympic medals, finishing second in the 400 relay and third in the 100 in the 2004 Games in Athens. Greene also collected five gold medals in the track world championships from 1997-2001.

"It's a little sad for me but it's happy at the same time because I've had a great career. I've done a lot of great things," Greene told reporters in Beijing, where he announced his retirement Monday.

"For the last couple of years, I've had nagging injuries that have stopped my training. So, I think it's better to just call it quits."