Seventeen years passed between Carl Lewis running the 100m in 9.86 seconds in 1991 and Usain Bolt going .14sec faster in May 2008, but the Jamaican sprinter's jaw–dropping performance on Sunday night has now reduced the record by a similar amount in just 15 months.
Bolt's performances at last year's Beijing Olympics had statisticians reaching for their calculators after his time of 9.69sec blew to pieces a model that had predicted with reasonable accuracy the progress of ever faster times in the 100m for nearly 100 years. Under that model, no one was due to run as fast as Bolt until 2030.
Following his latest world record breaking performance – 9.58 in Berlin's World Championships this week, achieved despite a car accident and after claiming to be just 85% fit – they might as well throw the model away altogether.
It was the biggest reduction in the record since electronic timing was introduced in 1968, when Jim Hines ran 9.95 at 1968 Mexico City Olympics and it took 28 years for Donovan Bailey to shave another .11 seconds from the record.
Further back, there had been a 20 year gap between Jesse Owens running the 100m in 10.2 in 1936, and William Williams shaving off a tenth of a second. In the same stadium as Owens' 1936 victory, Bolt clocked an average 44.72 km/hour between 60m and 80m.
Academics hailed his rare combination of stature, speed and power as a "one off" that may never be repeated. Just 12 months since Bolt, in his words, "blew the world's mind" in Beijing, he has again redefined the debate about how fast human beings will be able to run.
Dr Richard Ferguson, a senior lecturer in exercise physiology at Loughborough University, said Bolt's 6' 5" frame was the key to his success, allowing him to cover the 100m in between 40 and 41 strides when his competitors take 45 to 48.
"He's a good five to six inches taller than his competitors," he said. "His muscles will be slightly longer. If you have longer legs then you have longer muscles, which can generate more speed and more velocity." Taller athletes have historically been considered less suited to short sprints because they have fewer of the "fast twitch" muscle fibres that provide explosive speed, and find it harder to achieve a fast start out of the blocks. But Bolt has upset conventional coaching wisdom.
Ferguson said it was hard to separate physiological reasons from advances in nutrition, technology and training when attempting to explain why sprinters had got so much faster, so much more quickly, in recent years.
"It could be that he has a few more of those fast twitch muscles, but it's unlikely that he would have so many more than Tyson Gay, for example," he said. "He's tall but he's powerful too. He's something of a one off. I don't think we'll see anyone like him for a very long time."
Research showing athletes were getting taller and heavier faster than the rest of the population also suggested Bolt's height was a key factor.
In a paper published in the Journal of Experimental Biology last month, Adrian Bejan, professor of mechanical engineering at Duke University in the US, showed that elite sprinters had grown by 6.4 inches over the last century, while the population as a whole had grown 2 inches. Bolt is 11 inches taller than Eddie Tolan, the record holder in 1929.
Bolt has the hopes of an entire sport resting on his shoulders. Yet if he's feeling the pressure, he's hiding it well. The International Olympic Committee president, Jacques Rogge, said last week that TV ratings for the Beijing games showed younger people returning to the sport.
But athletics' world governing body, the IAAF, the organiser of this week's championships, recognises there is a big job to do to re-engage a global audience. Bolt will be a key asset when it launches the Diamond League series of domestic meetings next year, an athletics "Champions League" designed to give more coherence to the sport outside major championships.
As for how much faster Bolt can go, experts have given up trying to answer. His coach, Glen Mills, predicted after the Olympics that he could run 9.54 and was almost proved right. On Sunday night, Bolt commented: "I said anything could happen and it did. I'm happy with myself. Now I plan to do even better." 9.4 was the next goal, he said. Attention will now turn to whether Bolt can repeat his Beijing achievement and triumph in the 200m as well, the heats for which begin on Tuesday . "It's going to be fun," he said.
