DAEGU, South Korea (AP) - Usain Bolt will be going for a triple of golden triples when he settles into the starting blocks Saturday on the opening day of the athletics world championships.

Another sprint sweep of the 100 and 200 meters and the 4x100 relay will further cement his status as a sporting legend at only 25 — even if any superlative feat in Daegu will only be seen as a warmup for next year's London Olympics.

After three world records at the 2008 Beijing Games and two at the 2009 worlds in Berlin — the relay team merely ran the second fastest time in history — don't count on Bolt to break more marks in South Korea. Since a back injury last year, he is still looking for his sharpest form.

But more gold is all what counts now.

"World records can be broken but medals are forever," Bolt said.

His toughest challenge this year is not expected from U.S. sprinters after Tyson Gay injured himself, but from Jamaican teammate Asafa Powell, who has the top 100 time of the year at 9.78 seconds. But in their only confrontation this year in, Bolt edged him in Rome.
"He has been running fast for many years and deserves a lot of respect," Bolt said of his relay teammate.

Where victory lies at the finish line for Bolt, it comes much earlier for Oscar Pistorius.

The double-amputee sprinter from South Africa, who runs on carbon-fiber blades that replace his lower legs, will first race in the 400 heats on Sunday.