Nigeria's Tobi Amusan is facing a barrage of questions after she destroyed the 100 meters hurdles world record at the World Championships in Eugene, Oregon.
Amusan recorded a stunning time of 12.12 seconds in her semi-final run, beating the previous women's world record set by Kendra Harrison by 0.08 seconds and shattered her old personal best by almost 0.3 seconds.
Amusan then broke this time in the final, running a 12.06 - though this didn't count towards the record books as it was adjudged as being wind-assisted.
It was Nigeria's first-ever gold medal at the World Championships.
So unexpected was her time that sprint legend Michael Johnson, who was performing commentary duties at the event, wondered aloud if the timing system at the event had malfunctioned, especially given that 12 of the 24 runners across three semi-finals set new personal bests on their runs.
“I don’t believe 100h times are correct. 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,” Johnson wrote on Twitter.
“Heat 2 we were first shown winning time of 12.53. Few seconds later it shows 12.43. Rounding down by .01 is normal. .10 is not.”
A deeper inquiry, though, has led to claims that the shoes worn by Amusan might be the answer to questions posed by Johnson and others.
It emerged afterwards that she was wearing Adidas Adizero Avanti shoes - rather than traditional track spikes - athletic equipment which was designed for long-distance runners.
It was a decision made, she said, because these shoes have softer soles and helped to avoid relapses of plantar fasciitis which she was diagnosed with earlier this year - a type of injury which affects the soles of one's feet.
Adidas promoted the apparel as “like hitting fast-forward” and that they “provide a snappy, propulsive ride with high traction and reduce fatigue, so you finish 5km and 10km races with a kick”.
There is no allegation of illegality in Amusan's use of the shoes, given that they fall within the accepted standards used in such events.
“My abilities are not centered around spikes,” said Amusan, noting the controversy.
“I had patella fasciitis at the beginning of the season so that set me back for a while,” Amusan added.
“I spoke to Adidas and requested if I could get spikes with a softer sole. They recommended a lot of stuff and I feel comfortable in [the shoes], so I was using them basically the entire time.
“Speed-wise, I feel like I needed to work on my speed. I did 100m at the start of the season so that had a huge factor to come to play in the hurdles and I knew once I get the technical part out, I’d be fine.
The spikes do seem to have an impact in hurdles events. Sydney McLaughlin, wearing similar shoes produced by a different footwear brand, broke the 400m hurdles world record earlier in the same week.