"I know who won those seven Tours," Armstrong said in the statement. "The toughest event in the world where the strongest man wins. Nobody can ever change that. Especially (USADA CEO) Travis Tygart."
Vowing to "turn the page," Armstrong said he would "commit myself to the work I began before ever winning a single Tour de France title: serving people and families affected by cancer, especially those in underserved communities."
USADA said the doping evidence against Armstrong came from the statements of more than a dozen witnesses, including former teammates and associates. While Armstrong's defense was consistent - he had never tested positive for performance-enhancing drugs - USADA said that was irrelevant. Armstrong and his co-conspirators on the U.S. Postal Service team, it said, devised ways to cheat in ways that wouldn't be detected.
The anti-doping agency found Armstrong used EPO, blood transfusions, testosterone, cortisone and HGH during his career, and that "scientific data" showed he manipulated his blood with EPO or blood transfusions during his comeback to cycling in the 2009 Tour.
It also said witnesses would testify had alleged that Armstrong "encouraged them to use and administered doping products or methods, including EPO, blood transfusions, testosterone and cortisone during the period from 1999 through 2005."