'Athletics in an era of exciting possibilities but it also faces more questions than ever'

To get an idea of the challenging place athletics finds itself in right now, the media centre at Chicago's Hilton hotel immediately after the city's marathon on Sunday was an instructive place to be.

On a platform sat Brigid Kosgei, just minutes after running into the history books by becoming the fastest female over 26.2 miles the world has ever seen.

The Kenyan's astonishing performance completed a momentous weekend for distance running, coming just 24 hours after compatriot Eliud Kipchoge's historic sub two-hour effort over the same distance in Vienna.

On paper at least, both feats breathe new life into the sport, generating front-page coverage, lighting up social media, capturing the imagination and inspiring genuine awe among the general public, at a time when athletics is crying out for positive stories and new stars after the retirement of Usain Bolt.

Kipchoge's achievement was not without controversy of course, with many seeing it partly as a marketing stunt for the benefit of Nike, whose prototype shoes the Kenyan legend wore, and a publicity coup for petrochemicals giant Ineos.

Its logo was prominent throughout, the company's lavish funding ensuring nothing was left to chance, from the rotating pacemakers and laser-beaming support vehicle to the perfectly flat running surface.

Such artificial advantages meant Kipchoge's milestone did not count as an official world record. Kosgei's, meanwhile, most certainly did. Paula Radcliffe, the British woman whose 16-year-old record she obliterated, was at the finish line to congratulate her.

But on Sunday in Chicago, Kosgei could not escape questions from journalists about precisely which running shoes she had been wearing, and if they were the same as Kipchoge's. Her performance, coming so soon after his, intensifying the mounting controversy over whether the latest technology results in too great a marginal gain, and makes comparisons with previous eras of running unfair.

And she had to reassure those present that such a performance could be trusted, given the recent spate of doping scandals involving high-profile Kenyan runners.

After all, Kosgei has the same agent - Federico Rosa - as a number of banned Kenyan athletes, and while there is no suggestion of any wrongdoing by either of them, the association led to some awkward questions, the softly spoken world record holder insisting she was clean.

There was no sign of Mo Farah. Just two days earlier in the same room, he had angrily blamed journalists for the scrutiny he was under following the downfall of his former coach Alberto Salazar, banned two weeks ago for various doping violations, even seeming to suggest a racially motivated agenda by the media.

Neither Farah - nor any other of Salazar's athletes - were implicated in the scandal. But many will now wonder whether the fallout affected his performance on the streets of Chicago, the slowest marathon of his career.

If so, perhaps he would not be alone. After all, two other athletes with links to Salazar - Americans Galen Rupp and Jordan Hasay - also struggled here, both failing to finish. Both are also now looking for a new place to train after Salazar's Nike Oregon Project (NOP) was dramatically shut down on the eve of the race as the sportswear giant - a sponsor of the Chicago marathon - tried to get a grip of a crisis that has done serious damage to its reputation.

Sadly, Nike CEO Mark Parker - implicated in the US Anti-Doping (Usada) case against Salazar for being aware of a testosterone experiment he conducted on the company's premises - was not made available to the media here in Chicago, though he has said he did not believe the test was breaking any rules.

This has been an extraordinary few weeks for athletics. Salazar's ban was announced in the middle of one of the most controversial World Championships, in Doha. The event will be remembered as much for the sight of empty seats and the oppressive heat as it will for the gold medals that Dina Asher-Smith and Katarina Johnson-Thompson secured so thrillingly for Great Britain.

Equally, it is impossible to think of Christian Coleman's 100m gold in isolation from the ban he narrowly avoided on a technicality in the build-up after three missed doping tests. Nor can one celebrate the incredible 1500m-10,000m double of Sifan Hassan without acknowledging her association with her former coach Salazar and the NOP which she joined in 2016.

The fall-out from Salazar's ban is far from over. Not when the disgraced coach intends to appeal and denies any wrongdoing. And not when the IOC wants the samples of all athletes who trained at the NOP to be retested.

UK Athletics (UKA) performance director Neil Black - here in Chicago to help Farah - may be leaving his post after facing criticism but other officials at the governing body will also be asked to explain their links with Salazar, who acted as a consultant to Britain's endurance runners for several years.

Was the UKA review that cleared Farah to continue working with his former coach in 2015 after the allegations of unethical practices were first aired in a BBC Panorama investigation robust enough? And will UK Sport, or maybe UK Anti-Doping, now feel the need for a further inquest into the decisions taken by one of the country's best-funded governing bodies?

But perhaps above all, the most important legacy of the Salazar case could be to force athletics to re-examine its relationship with Nike.

Whether in Doha, Vienna or Chicago, it is hard to avoid its presence.

From shoe technology and sponsorship, through to its links with the media and senior officials, and the support it gave Salazar in his legal battle with Usada, the scale of the influence the company wields in this sport is apparent.

The Salazar scandal has brought this all into considerably sharper focus.

And having been forced to defend the decision to take its flagship event to Doha, the IAAF must now start preparing for the 2021 World Championships in Eugene. The Oregon city is closely associated with Nike, whose birthplace is only a few miles away.

Expect fresh scrutiny of the IAAF's decision in 2015 to bypass the usual formal bidding process, and award hosting rights to the city, something that has since been the subject of investigations by both French prosecutors and the FBI.

Athletics finds itself in an era of exciting possibilities and brave new frontiers, but it also faces more questions than ever too.