Russian athletes Maria Abakumova and Tatiana Lebedeva have been stripped of their silver medals from the 2008 Olympic Games following a ruling by the Court of Arbitration for Sport (CAS).

Abakumova, runner-up in javelin, and Lebedeva, who finished second in long jump and triple jump, had their results in Beijing disqualified by the IOC following reanalysis of samples they supplied in China.

The former world champions tested positive for the prohibited substance turinabol.

Abakumova and Lebedeva sought to have the decisions overturned, but their appeals were dismissed.

A CAS statement read: "The CAS panel found that the appellants were unable to prove that the testing methods adopted by the laboratories, which led to the positive findings against each of them, were not scientifically valid in accordance with the standard required to be applied."

Track cyclist Ekaterina Gnidenko also had her appeal rejected after she was disqualified from the women's sprint event at the 2012 Olympics, having tested positive for the same substance.