Athletics: Olympic and world 100m champion Justin Gatlin has requested an arbitration hearing to prove he is innocent of deliberately committing an anti-doping violation.
The 25-year-old tested positive for testosterone last April but denies taking the substance after a test at the Kansas Relays.
Gatlin admitted that, as an athlete, he was personally responsible for any banned drug discovered in his system and accepted he had committed a doping offence.
The United States Anti-Doping Agency (USADA) last August said it intended imposing an eight-year suspension.
He had until today to lodge an appeal against the proposed USADA punishment and his legal representatives said the necessary papers have been filed.
The long-running case could take another three months before the arbitration meeting is held.
Gatlin was initially looking at a life suspension having provided a positive test in 2001 but was subsequently reinstated by the International Association of Athletics Federations.
The world governing body accepted he was using medication to treat Attention Deficit Order but said the test result would remain on his file. PA