Sport has been rocked by several high-profile doping scandals in recent months with Lance Armstrong stripped of his seven Tour de France titles after admitting using banned substances.

CNN: Tennis serves up new measures in the fight against doping

Rivals from Singapore's National University claimed to have achieved nearly 20% by doping nanotubes with lithium, though only at high temperatures.

ECONOMIST: Space-age soot

Operation Puerto was an investigation -- started by the Spanish police in May 2006 -- into the doping ring led by Doctor Eufemiano Fuentes, which involved high-profile cyclists such as Ivan Basso and Tyler Hamilton.

CNN: October 24, 2012 -- Updated 1231 GMT (2031 HKT)

It is wrong to jump up and down about Denise when a lot of high-profile athletes, of all nationalities, are coached by people who have been banned for doping offences.

BBC: Cram: Leave Denise alone

But his appearance in Beijing now rests on a ruling by a judge in London's High Court on Wednesday as Chambers bids to overturn a British Olympic Association bye law, which bans athletes with a doping conviction from competing at the Games.

CNN: Drugs cheat Chambers wins Olympic trial