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Usain Bolt said that advances in spike technology that could help wipe out his world records are laughable and that the new shoes also give an unfair advantage over any athletes not wearing them.
After athletes ripped through the record books in distance running with carbon-plated, thick-soled shoes, the technology has now moved into sprint spikes, where - although there is less time in a race for the advantage to make an impact - it is still enough to make a difference.
"When I was told about it I couldn't believe that this is what we have gone to, you know what I mean, that we are really adjusting the spikes to a level where it's now giving athletes an advantage to run even faster," Bolt told Reuters in an interview from Kingston.
The 100m and 200m world record holder competed in Puma spikes throughout his career.
"It's weird and unfair for a lot of athletes because I know that in the past they (shoe companies) 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," the eight-time Olympic champion said.
American Trayvon Bromell is favourite to take Bolt's 100m title in Tokyo.
He is the fastest in the world over the distance this year with 9.77 seconds, but the 2015 world 100m bronze medallist is less convinced about the impact of the shoes.
"I don't think there's a lot of data to show that they're having such a big improvement," Bromell, who runs for New Balance, told reporters last week.
"I know we (New Balance) are constantly building onto what we have to make the perfect spike, but for me personally as a runner I still feel like it's not enough data to really show."