Two race walkers have become the first Russian athletes to appeal their right to compete in the Rio 2016 Olympic Games to the Court of Arbitration for Sport (CAS).
A similar appeal has been launched by the All-Russia Athletic Federation (ARAF).
This follows the International Association of Athletics Federations' (IAAF) decision last week to continue its suspension of the national governing body.
Only Russian athletes who can prove they have operated in an effective testing system will be able to compete internationally at events including the Olympics, a requirement which, in practice, is limited to those based outside the country.
Race walkers Denis Nizhegorodov and Svetlana Vasilyeva each argue that a ban on the entire team is overly unfair.
"Competing at the Olympics is the main goal and main honour," said Nizhegorodov in comments posted on the website of agent Andrei Mitkov.
"Now they want to take away my chance to compete at the Olympics, even though I haven't done anything to cost me a place in Rio," added Vasilyeva.
"From bitter experience I understand that you can't wait and hope for a good result - you have to act."
Nizhegorodov won a 50 kilometres silver medal at Beijing 2008 before taking bronze four years later in London, while Vasilyeva is a rising star who won the European under 23 Championship title in 2013.
But both trained under Viktor Chegin, the notorious race walking coach of more than 20 athletes disqualified for doping offences who was banned for life from all sport-related activities in February.
Nizhegorodov was also among 14 Russians to test positive following re-analysis of Beijing 2008 doping samples, although his B-test returned negative.
A World Anti-Doping Agency report last week specially highlighted race walking when pointing-out how problems remain with Russian drug testing procedures.
Fifteen competitors at February's Russian National Walking Championship in Sochi either did not start, withdrew or were disqualified after being alerted to the presence of drug testers.
The IAAF claim that, because of the absence of effective testing, Russian-based athletes cannot be considered clean even if they have never failed a test.
Both athletes claim they will reject any opportunity to compete independently under the Olympic flag, currently seen as the only way Russian athletics team members could compete if the IAAF oes accept them.
"I'm a citizen of Russia, a great sports power. I don't agree with competing under the Olympic flag," Nizhegorodov said.
More appeals can be expected, with two-time Olympic champion Yelena Isinbayeva having also vowed to appeal to a Human Rights court.
But CAS President and International Olympic Committee (IOC) vice-president described the Russian testing system as "rotten to the core" last week, suggesting that CAS will not view the appeals sympathetically.
More discussions on Russian participation are expected to take place here tomorrow at an Olympic Stakeholders Summit.