In these trying times, Allyson Felix is a godsend. She is a participant in the US Anti-Doping Agency's "Project Believe" programme, meaning she is regularly tested to ensure that her body is free of performance enhancing drugs.
The American is among the favourites for the 200 metres. She won the title at the Olympics in London last year. In fact the London games were a treat for the 27-year-old Californian.
She also collected gold in the 4x100 metres relay and the 4x400 metres relay, thereby becoming the most successful female track athlete at an Olympic Games since 1988.
Felix warmed up for Moscow with a comfortable 22.41 seconds at the anniversary games in London in July.
Back in May she claimed the 200 metres race at the inaugural IAAF world challenge in Beijing.
But her main threat will come from Murielle Ahouré from Côte D'Ivoire.
She won their Diamond League encounter over 200 metres in Rome in June in 22.36 seconds. And the Ivorian went to the Diamond League meeting in Monaco in July and claimed the 200 metres in a scorching 22.24 seconds. Ahouré hasn't lost any of her three races over 200 metres this season.
It's an impressive set of results for the 25-year-old from Abidjan. Last year she was a distant sixth as Felix grabbed the Olympic glory in London. In Moscow, the African, who trains at the University of Miami, she could well be in front of Felix.