MOSCOW – A beat or two after 9.50pm local time on Sunday the eight fastest men in the world will drop to their knees. Then, after a frenzied polka of flashlights around the Luzhniki Stadium, a pistol will puncture the sky and the silence.And the 100m – the grandest and briefest show at these world championships – will be under way.When it comes to the thin line between incredulity and suspicion, the men’s 100m walks not so much a tightrope as a piece of floss. That impression, forged in the Ben Johnson era of the late 80s, was merely hardened following the positive drug tests of Tyson Gay and Asafa Powell, the second and fourth fastest 100m runners in history.But Donovan Bailey, the Canadian who followed in Johnson’s footsteps by winning 100m gold at the world championships and Olympics – but did so clean – believes the primal allure of the event remains strong."The 100m will always be the blue riband race, no matter what,” he says. "It is the only event at the Olympics that stops the world. Only a World Cup final can match it."Our sport has taken a slight black eye but come Moscow everyone will be watching to see what Usain [Bolt] is going to do and if anyone can challenge him.”Dwain Chambers, one of the sport’s more perceptive voices on drugs since serving his ban for taking the designer steroid THG, admits he is not sure whether the 100m is cleaner now than it was a decade ago. "It’s sad to see that people I look up to have fallen in the same trap that I once did,” he says. "They should look at what I went through. It’s been a tough road for me.”But ask Chambers whether the 100m has lost any of its lustre and he demurs. "I don’t think so because everybody’s still excited to see Usain Bolt,” he says. "People want to see how fast he can run and what he can achieve. Even those chasing him want to see how fast they can go behind him.”Bolt is athletics’ biggest star and its Atlas. But you wonder what would happen if injury – or worse – intervened. If Bolt is carrying the burden of the sport on his shoulders, there was little sign of it when Jamaica’s sprinters trained on Thursday. The smiles were easy, the vibe relaxed. Bolt did not speak to the media but instead trained, put his arms around his fellow athletes and laughed away, even when the team masseuse was kneading Mueller massage lotion deep into his calves and thighs.Meanwhile Warren Weir, the young Jamaican who took bronze in the 200m at the London Olympics in 2012, was promising that his team-mates would "give people good news after the bashing our sport has gotten” by winning well and clean in Moscow. "Yes, you can still believe there are clean athletes out there,” he said. "I myself am one of the clean ones. You can’t bash all for some.”Jamaica’s new head coach, Michael Clarke, was later asked about Victor Conte’s comments that his country was years behind in testing athletes. He disagreed. "I think we are slowly keeping pace with what’s expected,” he said, which sounded a typically Jamaican way of doing things– except, of course, when it comes to sprinting. A follow-up question about how to deal with cheats was blocked by Jamaica’s press officer, Dennis Gordon, who told him not to take any questions about doping.Bailey, who will be commentating from Moscow for BBC Radio 5 Live, is clear about the punishments that should be meted out. "If it was up to me, it would be a lifetime ban,” he says. "It should be like the false start. It doesn’t really matter who you are. Even if you are a global superstar, if you false start once you’re out. It should be the same thing with drugs.”He also holds no truck with those who blame supplements for positive tests. "Athletes should know what they are putting in their bodies,” he says. "That’s the deal you sign with the IAAF and with your federation."I knew every morsel of food I put in my body. I knew what kind of massage oil my masseuse used. It’s crazy the sacrifices you have to live by but I recognised it was my life brand.”Bailey, incidentally, believes Gay and Powell "have been stupid rather than cynical” and is just as emphatic when asked if anyone can beat Bolt on Sunday night. "No,” he says. "He can make 100 mistakes between the blocks and the finish line and still win.”Millions will watch the race, enthralled by every 9.something seconds of it, giddily smiling as Bolt hyper-accelerates away from his rivals again.Despite the scandals, despite the doubts, ‘twas ever thus.