The fight between Lance Armstrong and the U.S. Anti-Doping Agency is over:
"There comes a point in every man's life when he has to say, 'Enough is enough,'" Armstrong, 40, wrote in a statement emailed to The Times and other news agencies.
"For me, that time is now. I have been dealing with claims that I cheated and had an unfair advantage in winning my seven Tours since 1999."
Armstrong's attorneys asked a USADA attorney to turn the matter over to UCI, the international cycling union, but USADA maintains it retains jurisdiction to strip the titles.
Armstrong never tested positive for performance-enhancing use during his decade-plus of Tour races.
Now, as he abandons his impassioned fight against anti-doping authorities, the perception of an American hero who rallied from cancer to become champion of perhaps sport's most demanding endurance test has been recast.