Lance Armstrong is 'unaffected' by claims he was at the centre of a doping scandal

Lance Armstrong: I'm unaffected by furore, says American

The US Anti-Doping Agency has revealed its reasons into why it banned him for life in August, accusing his US Postal Service team of "the most sophisticated, professionalised and successful doping programme that sport has ever seen".

But Armstrong, writing on Twitter, said that he was concentrating on his charitable work.

"What am I doing tonight? Hanging with my family, unaffected, and thinking about this," he wrote on his account @lancearmstrong, linking to his Livestrong foundation website and a series of fund-raising events for cancer research.

Eleven former team-mates gave evidence against Armstrong - who battled back from life-threatening cancer to win the Tour de France seven times - accusing him of taking banned substances and enforcing a doping culture within the team.

A former team-mate of Armstrong claims the disgraced cyclist should not be singled out for criticism despite the damning findings of the USADA.

Australian Patrick Jonker, who rode for Armstrong's US Postal team in 2000, believes such was the problem with drugs in cycling at the time to focus solely on one rider is not right.

He said: "Reading the report, I don't think Lance could have acted as the sole power behind this.

"I believe you must have had the knowledge of a doctor to enforce this.

"To crucify Lance and only Lance would be unfair, they need to crucify the sport during that era."

Although drug-taking was seemingly rife during the early part of the last decade, Jonker, who insisted he had never taken performance-enhancing substances himself, denied everyone at US Postal was involved.

"During that period, I was definitely aware that there were athletes using performance-enhancing drugs but I don't believe it was to the extent that USADA are coming out with," he added.

"The USADA were saying that in the Dauphine race three weeks before the Tour de France that there was a blanket use of performance-enhancing drugs in that particular race by the team and I was in the team with Tyler and Lance.

"The USADA pointing the finger at pretty much everyone is unfair.

"Me, myself, I am pretty sure the majority of the team were not taking drugs.

"In cycling then there was a problem but it was not a blanket."