Monte Carlo awoke this morning to the persistent rumble and crackle of thunder interspersed with stagey sheet lightning. It rained, hard. And the muggy air of the previous evening was cleared.

It would be nice to think the impending IAAF Diamond League meeting here will have a similarly restorative effect upon world athletics, which has swirled with rumour, suspicion and speculation since Sunday's slew of doping positives involving, among others, two of the sport's pre-eminent sprinters in Asafa Powell and Tyson Gay.

Gay, who has freely admitted a transgression although it is as yet unclear what errant substance is involved, was to have raced here. He can't now. Meanwhile, Powell's manager, Paul Doyle, has defended his man by implicating the trainer who has been working with the sprinter since May, Chris Xuereb, accusing him of providing supplements which have led to the positive test. Xuereb also began working at the same time with Powell's fellow Jamaican Sherone Simpson, the Beijing 2008 Olympic 100 metres silver medallist, who also faces suspension following an adverse test.

Asafa Powell, whose positive doping test was revealed on Sunday, insists he has never taken any illegal substance knowingly and now his manager has blamed supplements supplied by a new trainer

Both athletes deny knowingly taking any illegal substance. Meanwhile, Xuereb, as you might expect, denies giving them any illegal substance, adding: "I am extremely disappointed that these athletes have chosen to blame me for their own violations."

Xuereb says his main role with Powell and Simpson was "to provide soft tissue massage therapy as well as nutritional help".

All very confusing. All very worrying. All very familiar.

Justin Gatlin, the Athens 2004 Olympic 100m champion who was subsequently banned for testosterone and is now back on the circuit – and fourth fastest in the 2013 world lists for the distance, maintained that his positive test had come as a result of a masseuse with a grudge deliberately using a cream on him that contained banned substances.

That claim was disputed. Naturally. And it had no effect in terms of mitigating his punishment. 

Given the number of incidents there have clearly been misjudgements rather than deliberate cheating in terms of sports people testing positive – not just in athletics, but across the board – you would hope that those operating at elite level would have everything safe and sorted. But this is clearly not the case.

I flew in to Nice airport yesterday with three happy Jamaican athletes due to compete tomorrow  at Monaco's Stade Louis II – even though that count went down to two happy athletes when one discovered their luggage had not turned up – and we were delayed in getting to our transport while one of them sought out the massage table they had brought with them. The idea that one or any of these young people could be made very unhappy, for a long time, because of a mistake that might be made by a trainer was depressing indeed.

But once more we come to the hard fact that, while mistakes are made, such errors also have the possibility of being cited as an excuse for real misdemeanours. There is no real way of knowing.

Years ago, when I was writing a book with Britain's Olympic 400m silver medallist Roger Black, I asked him about doping in the sport. "The only person who can really know if I am clean is me," he said.

So now we are in the same old cycle – is this a bit Freudian round the edges? – in athletics, a cycle of accusation and denial. At such times, the sport requires to revivify itself to the wider world with good news, with clean performers. It is a time for standard bearers.

The cataclysmic weather here this morning put paid to a meeting-promotion exercise which would have seen Mo Farah, Britain's Olympic 5,000 and 10,000m champion, touring the streets in an open-topped bus.

Mo Farah, Britain's double Olympic champion, will hope to provide athletics with some good news after the bad when he races the 1,500m in the IAAF Diamond League meeting in Monaco

Instead, with the thunder still rolling around, Farah gave an early press conference in which he responded cautiously to the idea that athletes such as he had an additional weight on them to provide good news for the sport after bad, and to renew the sport's appeal to the wider viewing public.

"I've just come from a training camp in St Moritz, so I don't know all the details about what has being going on this week," he said. "But for myself I work hard, and I have got to give up one hour of every day to be open for testing no matter where I am in the world. It's important that we see good things happening in athletics. And sometimes the bad things get covered more than the good things. But we have just got to do what we can ourselves. That's all we can do."

Farah will be doing a 1,500m in Monaco to sharpen himself up for the IAAF World Championships in Moscow, which are only 23 days away. Fingers crossed, he will provide reasons for further celebration in the sport as he seeks to earn the 10,000 title which so narrowly got away from him at the 2011 World Championships in Daegu.

As for the 100m – well, no Gay, no Powell. And – following this week's announcement that Yohan Blake has failed to recover from the hamstring injury which has troubled him all season – no defending champion.

Gatlin will be there, and looks an increasingly strong contender. Usain Bolt, the man whom Farah readily describes as an icon in the sport, will be there, however. It is time for the standard bearers to step up once again.

Mike Rowbottom, one of Britain's most talented sportswriters, covered the London 2012 Olympics and Paralympics as chief feature writer for insidethegames, having covered the previous five summer Games, and four winter Games, for The Independent. He has worked for the Daily Mail, The Times, The Observer, The Sunday Correspondent and The Guardian. To follow him on Twitter click here.