How 'lightning' Bolt Cost Himself 0.14 Seconds

Had the world record sprinter Usain Bolt not begun his chest-beating celebrations 20 meters before the finish of the Olympic 100 meters final in August he would have smashed his world record by a further 0.14 seconds, according to physicists who have analyzed the race.

The supremely confident Jamaican runner did shave 0.03 seconds off the previous world record of 9.72 seconds - which he had set in May this year. But the researchers have calculated that had he kept running he would have clocked up a time of 9.55 seconds.

The 22-year-old sprinter also won Olympic gold in the 200 meters final with a record time of 19.30 seconds. "I just blew my mind and blew the world's mind," he told reporters at the games.

Hans Eriksen, of the institute of theoretical astrophysics at the University of Oslo in Norway, and colleagues analyzed television footage of the race, focusing on "Lightning Bolt" and the second-placed athlete, Richard Thompson.

Both sprinters slowed down in the final two seconds of the race, but Bolt's high jinks cut his speed more.

If he had slowed down by the same amount as Thompson he would have notched up a time of 9.61 seconds. But since Bolt comprehensively out-performed Thompson over the first eight seconds the scientists considered that that calculation might be too conservative. They estimate that if Bolt had decelerated less sharply he would have finished in a time of 9.55 seconds.

"We don't mean to say that this is the final and ultimate result," Eriksen told New Scientist magazine. "Instead, it's a fun application of simple physics, and we've done the best we can."

It is difficult to get accurate measurements from ordinary TV footage, which records at 30 frames a second or less, said Matthew Bundle, of the University of Wyoming, Laramie, who studies human locomotion. But he said the times estimated by the researchers were reasonable.