Michael Johnson has cast doubt over the accuracy of the timing of Tobi Amusan's world record in the 100m hurdles at the World Athletics Championships ©Getty Images

America's sprint legend Michael Johnson has found himself at the centre of a "racism" storm after he cast doubt over the accuracy of the timing system at the World Athletics Championships in Eugene.

The four-time Olympic gold medallist, working for BBC Television at the World Championships, questioned the performance of Nigeria's Tobi Amusan after she looked visibly stunned when she saw her winning time of 12.12sec in the 100 metres hurdles semi-final yesterday.

Her run at Hayward Field obliterated the existing world record - set by American Kendra Harrison in 2016 - by 0.08sec and was three-tenths of a second quicker than she had ever run before.

World Athletics awarded her a $100,000 (£83,000/€98,000) bonus for breaking the record.

Amusan went on to win the final with an even faster time of 12.06, but it did not count as an official world record due to a tailwind of 2.5 metres per second (mps) blowing during the event, above the legal limit of 2.0mps.

Nigeria's Tobi Amusan, second right, set the world record in a 100m hurdles race where many runners ran quicker than ever before ©Getty Images
Nigeria's Tobi Amusan, second right, set the world record in a 100m hurdles race where many runners ran quicker than ever before ©Getty Images

Johnson later amplified on his doubts on social media.

"I don’t believe 100h times are correct," the American wrote on Twitter.

"World record broken by .08! 12 PBs set.

"5 National records set.

"And Cindy Sember quote after her PB/NR 'I throughly I was running slow!'

"All athletes looked shocked."

Some social media users criticised Johnson, labelling the American athlete "bitter".

One tweeted: "Just because it’s not an American WR doesn't mean the times were incorrect."

Another fumed: "Michael Johnson are you naturally this dumb or do you have to put in effort?

"Why don’t you channel your energy to recovering from your stroke you Black racist!

"Toby Amusan is a world record holder and there’s nothing you can do about that."

Other experts claimed that the reason behind Amusan’s incredible performance was her choice of Adizero Avanti Tyo Tinman Elite shoes, manufactured by Adidas and designed for distance running rather than sprinting.

The spiked cleats have a soft sole containing a high-tech layer of carbon rods and foam, which led some to wonder if the super shoes - which Amusan said she wore after suffering tendonitis in the arch of her foot - had given her an unfair advantage.

But that does not explain the unexpectedly fast times clocked by the other runners.

Johnson later addressed the backlash, tweeting: “In questioning the times of 28 athletes (not 1 athlete) by wondering if the timing system malfunctioned, I was attacked, accused of racism, and of questioning the talent of an athlete I respect and predicted to win.

“Unacceptable.

“I move on.”