High-tech shoes and track spark fast times

TOKYO • As athletics records continue to fall at the Olympics, adulation and incredulity at such extreme examples of human endeavour are being followed by more sober reflection as fans try to quantify the impact of carbon shoe technology and the Tokyo track.

Endurance athletes on the road have spent the last few years insisting that it is their training and dedication, not their carbon-plated, thick-soled shoes, that are the key factors in a series of amazing records. Now, it is the turn of track athletes over the shorter distances.

Yet there is even some sort of civil war emerging between the lead protagonists, who argue about whose new "performance-enhancing" shoes are the fairer.

The two 400m hurdles races in Tokyo this week have given the most dramatic indication that "something odd is going on".

Kevin Young's 46.78 seconds record for the event stood for 29 years until Karsten Warholm chipped a piece off it last month. On Tuesday, the Norwegian clocked an astonishing 45.94sec, while American runner-up Rai Benjamin was also half a second inside the old record.

Warholm wore a pair of custom-made Puma spikes, with a carbon plate but a notably thinner insole than the Nike model worn by Benjamin and many others, which is at the limit of World Athletics' regulations.

He, nevertheless, criticised his rival for having "those things in his shoes, which I hate".

"I don't see why you should put anything beneath a sprinting shoe," Warholm said. "In middle distance, I can understand it because of the cushioning. But if you put a trampoline in, I think it's b******t, and I think it takes credibility away from our sport."

On those who say innovation should be embraced and those who claim the changes make historical comparisons, and the appreciation of records, pointless, he added: "We have the carbon plate but we have tried to make it as thin as possible.

"Of course technology will always be there. But I also want to keep it down to a level where we can compare results because that is important."

Benjamin dismissed Warholm's claims but one thing the two men were united on was the "crazy" track helped.

The designer of the Olympic Stadium track in Tokyo revealed the magic ingredient squeezed under a thinner than normal 1.4cm surface was rubber granules that help create small pockets of air.

"They not only provide shock absorption but give some energy return, at the same time a trampoline effect. We have improved this combination and this is why we are seeing the track has improved performance," Andrea Vallauri said.

"Every time there is an Olympic Games, we try to improve the formulation of the material and Tokyo has been no different.

"It is completely within the rules but it is also what we were asked to provide. It should also give them a push. It is difficult to say exactly but maybe a 1-2 per cent advantage."

REUTERS