Swimmer Yulia Efimova became the third Russian swimmer to challenge her Rio Olympics ban as the International Olympic Committee rejected blame for the Russia doping crisis.
A Russian wrestler, Viktor Lebidev, has also made an appeal against bans ordered over Russia's state-organised use of banned substances.
Efimova, who won a 200m breaststroke bronze medal at the 2012 London Olympics, follows Vladimir Morozov and Nikita Lobintsev in taking her case to the Court of Arbitration for Sport.
CAS confirmed the new appeals by Efimova and Lebidev.
The cases of Morozov and Lobintsev, also medal-winners in London and the Beijing Games in 2008, were heard by a CAS tribunal on Sunday with a new hearing set for Monday, CAS secretary general Matthieu Reeb told AFP.
Efimova's hearing will start Monday, he added.
Lebidev has launched his case against the IOC, wrestling's governing body and the Russian Olympic Committee.
Seven Russian swimmers were banned from Rio by FINA after the IOC ordered sporting federations to exclude any Russian competitors implicated in an investigation into Russia's doping scandals by Canadian lawyer Richard McLaren.
McLaren's report for the World Anti-Doping Agency (WADA) said there was a state-organised doping scheme in Russia, with the secret service helping the sports ministry to manipulate samples at the 2014 Sochi Winter Olympics and other major events in Russia.
At least 117 of the 387 sportsmen and women that Russia had wanted to send to Rio have been excluded. In parallel there have recriminations over who is to blame for the shadow cast over the Rio Games.
IOC president Thomas Bach rejected suggestions at a press conference that the chaos represented a "huge failure" for the IOC.
"No. And this is for very obvious reasons," he replied.
"The IOC is not responsible for the timing of the McLaren report.
"The IOC is not responsible for the fact that different information which was offered to WADA already a couple of years ago was not followed up.
- 'Games a la Brazil' -
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Russian anti-doping agency whistleblower Vitaly Stepanov says he first began passing information to WADA in 2010. Doping in Russian athletics was exposed in a German television documentary in 2014.
WADA has said it did not have the power to act on the information and insisted that its priority was to protect Stepanov and his wife Yulia Stepanova, who are now in hiding in the United States.
Adding to his thinly veiled attack on WADA, Bach said the IOC was not responsible for the accreditation or supervision of anti-doping laboratories in Russia.
"So therefore the IOC cannot be made responsible neither for the timing nor for the reasons of these incidents we have to face now and which we are addressing and have to address just a couple of days before the Olympic Games," Bach said.
Bach also insisted the doping scandal would not taint the Rio Games.
"I don't think this event will be damaging. I trust people will realise the difficult situation we are in. We did our best to address the situation in a way to protect clean athletes."
Three IOC executive members have been named to make a final decision on which Russian athletes will compete in Rio once the individual federations have made their lists.
The panel is made up of Ugur Erdener, president of World Archery and head of the IOC medical and scientific commission, Claudia Bockel of the IOC athletes commission, and Spanish IOC member Juan Antonio Samaranch.
The IOC said the Russian team will be finalised before Friday's opening ceremony at the Rio Olympic stadium.
The Rio Games has also faced criticism over the state of the athletes' village and the readiness of some venues. On Sunday thousands of people -- including 4,000 in Rio -- took part in demonstrations against suspended president Dilma Rousseff.
But Bach insisted that the organisation of the Games is "coming together".
"There will be, as always be some last-minute challenges," said Bach.
But he added that the Brazilian authorities had acted quickly in recent months and "we are more confident than ever that we will have a great Olympic Games a la Brazil".
The Games, with an estimated 10,500 athletes, start Friday and finish August 21.
