It is the sad side-effect of a tainted sport, but Tyson Gay admits that the tag of “the fastest man on earth” comes with attendant caveats about drugs and cheats. It is the price of speed in the modern era and it is why the American wants to break the 100 metres world record away from the curtain-twitchers and innuendos at home.

“I appreciate not having to answer the drug question,” he said, but because this is sprinting he was then forced to do just that.

Gay is surfing the crest of a wave, an image that may be fitting if the poor weather persists in Sheffield for tomorrow’s Norwich Union Grand Prix. He recorded 9.84sec at the United States Championships in Indianapolis and followed that with 19.62 in the 200 metres, a time that is second only to Michael Johnson’s world record.

He has even gone faster than Asafa Powell’s 100 metres world mark of 9.77 and, although that run in New York was deemed to be wind-assisted, he should be a rising star. Instead, he says few people recognise him even in Kentucky, his home state, and that the American public now has an ingrained cynicism about track and field.

“The focus is always on drugs,” he said. “Someone wrote an article insinuating that I must be on drugs to run that fast. There is not the respect. I enjoy running in Europe because they talk about the racing. But you know, the previous two record-holders [Tim Montgomery and Justin Gatlin] have tested positive, so I know where they’re coming from. I’ve had some people telling me that ‘what you did at the US nationals was better than Justin Gatlin and he’s on drugs’.”

Gatlin’s ban was a body blow for the sport, but there is now the prospect of Gay and Asafa Powell forging a restorative rivalry. On Tuesday in Lausanne, Switzerland, Gay ran a bend that had his rivals going round a metaphorical one, the time of 19.78 defying the cold.

“Coming to Sheffield, the hype has been huge,” he said in his gossamer whisper. “Everyone is talking about breaking the record with the fast track. It’d be a great place, but the win is the main thing.”

Gay will run in Crystal Palace next month, but Powell has ruled out a head-to-head before the World Championships in Osaka. The 24-year-old said that he would take a gold medal in Japan in place of a world record in Sheffield, although the weather and injury may rule out a fast time tomorrow, anyway. “Sometimes I like the rain, while other people can get down psychologically,” he said. “My knee is swollen a bit, but it’ll be fine.”

A bizarre subplot to the Gay story is that his rise has come while his coach, Lance Brauman, is in prison in Texas. He was jailed last November for fraudulent payment of athletes from student assistance programmes and keeps in contact with his man via phone calls and letters.

“He called me yesterday,” Gay said, unaware that the association with a convicted criminal does little to heal the sport’s festering wounds. “He watched me on television and he wrote a whole book of workouts. I’ve been to see him twice, too. He called me yesterday and let me know it’s 45 days until he gets out.”

The British public will relish a sight of this year’s phenomenon, but Gay insists that Powell, who returned from injury to win in Rome last night, is the favourite to win in Japan. “He has the record, all I’ve done is run a few fast times,” Gay said. “He is capable of running 9.7.” With Osaka’s fast track, Gay said that he expects the record to have fallen by the end of the championships.

Also part of a stellar cast in Sheffield are Carolina Klüft, who is unbeaten in the heptathlon for six years and will make her outdoor British debut in the 100 metres hurdles, and Liu Xiang, the 110 metre hurdler who is a megastar of Beckham proportions at home in China.

Tim Benjamin, the Briton who finished fifth in the 400 metres at the 2005 World Championships, misses out with a foot strain and Phillips Idowu, the triple jumper, will also be absent after failing to recover from a back injury.

The 100 metres is top of the bill, though, and British fans will hope that Marlon Devonish, who ran a lifetime best of 10.06 in Lausanne on Tuesday, will continue his form. However, Mark Lewis-Francis, his compatriot, will miss the event on the instructions of the UK Athletics doctor because of an injury.

As for Gay, asked how he could change the suspicious minds at home, he said without irony: “Continue to stay positive.”

Fast figures

Born: August 9, 1982 in Lexington, Kentucky

Height: 5ft 11in (1.80m)

Weight: 11st 11lb (75kg)

Lives: Lexington, Kentucky

Education: Marketing degree from University of Arkansas

Events: 100 metres, 200 metres, 4 x 100 metres

Personal bests: 100 metres 9.84sec, 200 metres 19.62

Achievements:

— US champion at 100 metres (2006, 2007), 200 metres (2007)

— 2006 World Cup 100 metres and 4 x 100 metres relay gold medal-winner

— World Athletics final 200 metres winner 2005, 2006

— 2005 US Championships 200 metres runner-up

— 2004 US National Collegiate 100 metres champion

— Gay won the 100 metres with a time of 9.84 – the second fastest ever into a headwind – at the AT&T USA Track & Field Championships in Indianapolis on June 22. Two days later he won the 200 metres in 19.62 – the second fastest ever.