BACKGROUND What is the «Osaka Rule» in relation to anti-doping?

Rio de Janeiro (dpa) - The so-called Osaka Rule was decided during the 2007 world athletics championships in Japan, when the International Olympic Committee (IOC) decidede to ban athletes with doping suspensions of more than six months from the following Olympics.

Then-IOC president Jacques Rogge said the measure was "to tell them if you cheat there will be no Olympic Games," predicting that this would be "a powerful deterrent."

But the rule was challenged by the American Olympic committee USOC before the Court of Arbitration for Sport (CAS), in order to have its 400-metres world and Olympic champion LaShawn Merritt compete at the London 2012 Games despite serving a 21-month ban. It argued that the Osaka Rule amounted to double punishment for one offence.

The CAS ruled in USOC‘s favour in October 2011 but left the door open for the IOC and the World Anti-Doping Agency (WADA) to amend their rule in the WADA Code accordingly which would then constitute one punishment.

But it was then decided for legal reasons to drop the Osaka Rule in favour of doubling the length of doping bans from two to four years for serious offences - a timeline that automatically covers the following Olympics.

After this year‘s allegations of state-sponsored doping in Russia, the IOC decided against a blanket ban for Russians in Rio, instead letting individual sports bodies decide their eligibility based on strict criteria, including that no athletes previously sanctioned for doping would be eligible to compete.

This in practice revived the Osaka Rule in the Russian case.

On Thursday, the CAS dealt a blow to this approach, ruling that the Osaka Rule cannot be used to ban two Russian rowers and a swimmer from the Rio Games for previous anti-doping offences.

Thursday‘s ruling forces rowing governing body FISA to reconsider Anastasia Karabelshikova and Ivan Podshivalov‘s cases and in theory opens the door for previously banned Russians to contest being barred from Rio. The same applies for swimmer Yulia Efimova.