Landis' testimony at the hearing lasted 75 minutes

The American tested positive after winning last year's Tour de France but told the hearing that cheating was against his principles.

"It wouldn't serve any purpose to cheat and win the Tour because I wouldn't be proud of it," said the 31-year-old.

He added he would be 'forever tainted' by allegations of cheating.

It was the sixth day of the nine-day US Anti-Doping Agency hearing.

"To me, bicycle racing was rewarding for the pure fact that I was proud of myself when I put the work into it and I could see results and get something out of it," said Landis.

The cyclist said he had been shocked after hearing the news that he had tested positive after stage 17 of last year's Tour.

"I didn't have an explanation for it and, when the world finds you have tested positive, it's a disaster," he said.

Landis also admitted that he had been in the same room when his manager Will Geoghegan phoned former Tour de France winner Greg LeMond and threatened to reveal he had been sexually abused as a child.

LeMond told the hearing last week that he received the anonymous phone call the night before he was due to testify.

Landis' lawyer later announced that the cyclist had sacked Geoghegan.

Landis' 75-minute testimony was given to three arbitration experts, who will determine whether he is guilty of doping.

If they do find against him, Landis faces a two-year suspension and the possibility of becoming the first Tour winner to be stripped of his title for doping.

However, the American could take the matter to the Court of Arbitration for Sport.

Although the Malibu hearing is scheduled to end on Wednesday, closing arguments will be presented by both parties at a later date with the time and venue yet to be determined.