Athletics' world governing body is being rocked by more doping allegations.
The Sunday Times claims the IAAF has suppressed a study which showed as many as a third of the world's top athletes admitted violating anti-doping rules.
The study by a German university claimed hundreds of competitors had told its researchers in 2011 that they'd cheated.
But the governing body says it is still working with the university and the World Anti-Doping Agency about publication.
