Cyclist Floyd Landis, who lost his Tour de France title after a positive drug test, has admitted systematic doping and accused fellow American Lance Armstrong of doing the same.
The Wall Street Journal reported that Landis acknowledged his own drug use and accused fellow cyclists of doping in emails he sent to cycling officials and sponsors.
Sports news site ESPN.com said Landis confirmed to them that he had sent the emails admitting the use of performance-enhancing drugs.
"I want to clear my conscience," he said. "I don't want to be part of the problem anymore."
Landis, who was stripped of his 2006 title after testing positive for elevated levels of testosterone, claimed he and other US cyclists conducted blood transfusions, and used steroids and a synthetic blood booster called erythropoietin (EPO), the reports said.
In emails addressed to officials from USA Cycling, the International Cycling Union and elsewhere, Landis alleged that Armstrong's longtime coach Johan Bruyneel introduced Landis to practices including steroid patch use and blood doping.
Landis also claimed Armstrong, a seven-time Tour de France winner, explained the doping process to him.
"He and I had lengthy discussions about it on our training rides during which time he also explained to me the evolution of EPO testing and how transfusions were now necessary due to the inconvenience of the new test," Landis wrote in one of three emails seen by the Journal.
Armstrong and Bruyneel did not respond to the newspaper's request for comment.
Speaking to ESPN, Landis admitted "misjudgments," but said he felt no guilt at having taken performance-enhancing drugs.
"With the benefit of hindsight and a somewhat different perspective, I made some misjudgments," he said.
"I don't feel guilty at all about having doped," he added. "I did what I did because that's what we (cyclists) did and it was a choice I had to make after 10 years or 12 years of hard work to get there.
"My choices were, do it and see if I can win, or don't do it and I tell people I just don't want to do that, and I decided to do it."
He told ESPN that he has offered to share his journals and diaries with US anti-doping authorities and has given officials information about how cyclists are able to beat drug tests.
Landis was banned from racing for two years after failing his drug test, making his return in January 2009.
He lost an appeal before the Court of Arbitration for Sport (CAS) which threw out his case in June 2008 and ordered him to pay $US100,000 in judicial costs to the American anti-doping agency.
Landis' attempts to clear his name are believed to have cost him some $US2 million.
Factbox on American cyclist Floyd Landis, who on Thursday admitted to using performance-enhancing drugs during his career.
* Born Oct. 14, 1975, in Farmersville, Lancaster County, Pennsylvania, into a community of Mennonites, a branch of the Christian Anabaptist church.
* Landis bought a mountain bike at 15 and won the first mountain bike race he entered.
* In 1995, he moved to California and became a full-time rider. Switched to road racing and joined seven-times Tour champion Lance Armstrong's US Postal team.
* Split with Armstrong in 2005. Joined the Swiss team Phonak and won inaugural Tour of California in 2006 as well as Paris-Nice classic and Tour of Georgia.
2006 TOUR DE FRANCE
* Battled back from nightmare in the 16th stage in the Alps to win stage 17 and set up Tour triumph.
* His Phonak team announced on July 26, 2006, Landis had tested positive for the male sex hormone testosterone. He was sacked by the team, which was later disbanded.
* International Cycling Union (UCI) announced on Aug. 5, 2006 the B sample analysis also gave a positive test. Landis protested his innocence and vowed to fight the case.
* On Sept. 20 2007, Landis was found guilty of doping by a US Anti-Doping Agency (USADA) arbitration panel and banned for two years. He appealed to the Court of Arbitration for Sport (CAS).
* On June 30 2008, CAS upheld USADA's verdict.
* In September 2008, Landis took the case before a US Federal court but it was dismissed.
* In January 2009, Landis returned with the domestic American team OUCH. He rode the Tour of Southland in New Zealand in November, finishing 17th overall with local team CyclingNZshop.com-Bio Sport.
* In January 2010, he joined the OUCH-Bahati Foundation Cycling Team.
* In February 2010, a French judge issued a warrant against Landis for suspected hacking into an anti-doping laboratory computer.
* Landis confesses to doping on May 20 2010 in a series of emails and accuses other riders of also cheating.
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