THE designer of the running track at Tokyo's Olympic Stadium has admitted the surface is giving athletes a "one or two per cent" advantage.
The Tokyo Olympic Games has seen a number of world and Olympic track records smashed over the past couple of days.
The most recent example being Norway's Karsten Warholm smashing his own 400m hurdles world record.
Warholm annihilated his own record by more than 0.7 seconds on Tuesday, clocking in a time of 45.94 seconds.
Funnily enough Team USA's Rai Benjamin - who came second - also broke Warholm's previous world record with a time of 46.17.
Puerto Rico's Jasmine Camacho-Quinn and Jamaica's Elaine Thompson-Herah smashed Olympic records in the 100m hurdles and 100m respectively.
Although watching athletes smash world and Olympic records is fun, it has, however, raised some questions about the track.
And one of its designers, Mondo's Andrea Vallauri, explained why some athletes such as Kyron McMaster - who came fourth in the 400m hurdles - described running on the track as like "running on air".
Vallauri said: "What you are seeing is evolution. Clearly every time there is an Olympic Games we try to improve the formulation of the material, and Tokyo has been no different.
"We have tried to improve by adding an extra compound. The track is very thin - 14mm. But we have added these rubber granules.
In lab testing we can see the improvement. It is difficult to say exactly but maybe a one or two per cent advantage.Andrea Vallauri
"How best to describe it: in the lower layer of the track is this hexagonal design that creates these 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.
"In Rio (in 2016) the track was called WS. This new one is called WSTY, for Tokyo. It’s the latest evolution of the track.
"It is completely within the rules but it is also what we were asked to provide; two components.
"To protect the health of the athletes, to avoid trauma, but it should also give them a push, let me say it like that.
"In lab testing we can see the improvement. It is difficult to say exactly but maybe a one or two per cent advantage.
"It is all prefabricated so every lane is the same, and the run-ups for the long and triple jumps also. The production is the same as a Formula One tyre."
The track isn't the only thing raising questions at the Tokyo Olympic Games.
The production is the same as a Formula One tyre.Andrea Vallauri
Nike's 'super shoes' are causing a stir with 400m hurdle winner Warholm slamming Benjamin - despite beating the American - for wearing the Nike Air Zoom Maxfly shoe, which has an air pod that provides even greater spring in each of the athlete's steps.
Warholm said: "If you put a trampoline there I think it’s b*******.
"I think it takes credibility away from our sport. I don’t see why you should put anything beneath a sprinting shoe."
Usain Bolt also joined in on the debate and blasted the unfair advantage the 'super shoe' is giving athletes.
He told Reuters: "When I was told about it I couldn’t believe that this is what we have gone to.
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"That we are really adjusting the spikes to a level where it’s now giving athletes an advantage to run even faster.
"It’s weird and unfair for a lot of athletes because I know that in the past [manufacturers] actually tried and the governing body said, ‘No, you can’t change the spikes’.
"So to know that now they are actually doing it, it's laughable."
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