Russian athletes stand to lose an Olympic gold medal and two world championship golds after the Court of Arbitration for Sport ruled the selective doping punishments imposed by Russian authorities were too lenient.

The court ruled that the Russian anti-doping agency had wrongly imposed bans which were timed in a way that meant the six athletes' results were not annulled and allowed them to keep major titles.

The decision means that a 2012 Olympic gold medal in the men's 50-kilometer walk is likely to pass from Russia's Sergei Kirdyapkin to Australia's Jared Tallent, subject to IAAF and IOC confirmation. China's Si Tianfeng would move up to silver, with bronze for Ireland's Rob Heffernan.

The six cases were based on the biological passport system, which tracks unusual blood values for signs of doping.