DENVER (AP):

TRYING TO get Usain Bolt to confirm whether he'll run the 100 metres in Beijing could be as hard as catching him if he does.

The Jamaican sprinter, fresh off setting the world record in athletics' iconic event last weekend, backed off yesterday from his earlier guarantees that he'll run the 100 at the Olympics in August.

A specialist in the 200 who only recently seriously began competing in the 100, Bolt said he still plans to run both races in Jamaican nationals at the end of the month to keep his options open. But he stopped short of saying he'd be in the 100 at the Olympics, contradicting what he had said in a statement released by his agent on Monday.

"I said that, but my coach still hasn't decided," Bolt said in a conference call with reporters. "But I'll be doubling at trials. I'm not exactly sure what I'm doing."

Training in earnest

He said, as he has many times, that the 200 is his priority. He'll start training in earnest for the 200 soon and will run a 200 in competition for the first time this year at the Golden Spike, June 12 in Ostrava, Czech Republic.

"I'm doing good in the 100, but I prefer the 200 because I've dedicated my whole life to it," Bolt said.

As for his second-favourite race, well, it'd be hard for him not to love that one too.

The athletics world is still buzzing about Bolt's record time of 9.72 seconds on Saturday night in New York in what he said was only his fifth official race at that distance.

He's been working hard on his starting technique - more important in the 100 than in any other event -and his start on Saturday night was perfect. He was ahead of American Tyson Gay from the start and beat Gay easily, finishing .02 seconds faster than the record previously held by countryman Asafa Powell.

No doping

This came about a month after Bolt recorded a 9.76. Such a stunning climb in such a short time is bound to raise questions in athletics - a sport constantly hammered by doping allegations and stories of unclean competition.

Bolt fielded the expected doping questions yesterday, saying he's clean and that his rapid rise shouldn't come as such a surprise.

"I've been running good since I was 15," the 21-year-old said. "This is no surprise to me, no surprise to a lot of people because I've been doing it since I was young."

He said a second-place finish last year in the 200 at worlds caused him to rededicate himself, spend more time in the gym, less time partying.

"I've matured more," Bolt said. "Getting so near to gold and not winning it, it changed my attitude a little more. I'm more serious now. I really want it. I've done more training, more technical stuff than I did."