By John Mehaffey
LONDON (Reuters) - A mythical athlete from the Caribbean clocks 8.99 seconds over 100 meters in the year 2909. Some centuries earlier, in 2245, a Kenyan runs the marathon in one hour, 57 minutes, 58 seconds.
These fictitious case studies, according to John Brenkus in his book "The Perfection Point" which calculates ultimate limits for a host of sporting achievements, contain the fastest times humanly possible for the shortest and longest events on the Olympic athletics program.
Speculation about the possibilities at either end of the spectrum has been stirred by the astonishing performances of Usain Bolt over 100 meters in 2008/09 and a remarkable marathon performance by Patrick Makau last year.
In 2008, Jamaican Bolt set a world record of 9.72 seconds in his first competitive season over the 100. At the Beijing Olympics he clocked 9.69 in the final. A year later he ran 9.58 at the Berlin world championships.
Kenya's Makau slashed 21 seconds off Haile Gebrselassie's world marathon record with a time of two hours, three minutes, 38 seconds in Berlin last September. Such is the strength of Kenyan distance running that even this landmark was not enough to win selection for the London Olympics.
Startling as Bolt's performances were, Brenkus, the host and executive producer of the Sports Science show on the ESPN sports channel, believes they are in line with the expected progression of the men's 100 meters record.
"The real thing that Bolt shattered is just how tall a sprinter can be," he said in a telephone interview with Reuters. "Not even long ago people were just not simply that tall."
Bolt stands 1.96 meters tall. "In a lot of ways the height is a disadvantage out of the blocks, but once he is up to speed his height becomes an advantage," Brenkus added. "His stride length and stride frequency is phenomenal.
"To me it is going to be really interesting to see how it evolves; are there going to be a lot more sprinters who are tall who are slower out of the blocks and going to be faster than average speed throughout or is it going to revert to being smaller?"
Brenkus's ultimate 100 time is based on Bolt's Beijing run.
The perfect race would start with a reaction time to the gun of 100 milliseconds, compared to Bolt's 165 in Beijing. The athlete would be aided by the maximum allowable following wind of four meters a second (there was no wind at all in Beijing).
The race would take place at the highest allowable altitude of 1,000 meters (Beijing was virtually sea level) where the air is thinner. Finally, 0.1 of a second is deducted to allow for Bolt's showboating over the last section.
These factors would produce a time of 9.36 seconds, which, coupled with a maximum possible physiological improvement in the present human species of 3.7 percent, would result in a time of 9.01.
Mankind's determination to break arbitrary barriers, says Brenkus, would produce the extra two-hundredths of a second needed to set the ultimate time of 8.99.
Brenkus said Bolt's Berlin race where there was a slight following wind, a marginally faster start and no celebrating in the final 20 meters was in line with the projections.
"The Berlin race doesn't surprise me all that much. What will surprise me is if the record goes to 9.3 in the next three years. It's going to be hundredths of a second from here," he said.
Brenkus was reluctant to predict just how much faster Bolt could go. "There are so many factors that are involved," he said. "We just don't know - injuries, hamstrings, how do you calculate that?"
Makau's run in Berlin revived talk of a two-hour marathon. The degree of difficulty is underlined by the current world half-marathon record of 59 minutes 23 seconds, which means an athlete would have to run 42.195 kms at practically the same speed.
"We're pretty close to the top, we're pretty close to maxing out," said Brenkus. "Obviously it will be less, but there isn't a half-hour of time left which we can shave."
The decisions to step up to the marathon by firstly Paul Tergat and then Gebrselassie, who contested a tremendous 10,000 battle at the 2000 Sydney Olympics, produced world records for both men.
Gebrselassie then became the first person to run under 2:04.
Brenkus believes it might need somebody with the basic speed of a 1,500 meters/mile runner to make the next breakthrough.
"My feeling, and I feel pretty strongly about it, is that we are nearly topping out (in the marathon) as a species and when you start factoring that in you have to speculate is it going to be the miler or the marathoner just decreasing his time?
"I think it's more likely going to be the miler. If you have to do it once and lay it down and leave it all out there it's possible to get that two-hour marathon.
"The marathon is approaching that magical round number of two hours. I don't think it's the limit but we are certainly going to center our minds around it. But if 1:55 was the magical number everybody was shooting for would we be below two hours now?
"It's really hard to calculate how much is the mental barrier. We create our own barriers, and we pick them just because they are convenient and easy."
(Editing by Clare Fallon)