Lance Armstrong was officially stripped of his seven Tour de France titles Friday by the U.S. Anti-doping Agency, capping a decade of speculation that he had cheated to earn the victories. The organization also banned him for life from further competition.

In an act widely viewed as an admission of guilt, Armstrong announced Thursday night he would not enter arbitration to fight charges of doping in a case brought against him the USADA.

"There comes a point in every man's life when he has to say, 'Enough is enough.' For me, that time is now," Armstrong said in a statement Thursday night.

USADA swiftly announced they would move to strip Armstrong of his seven Tour de France titles and ban him for life from further competition, though Armstrong disputed the right of USADA to strip him of his Tour de France wins.

"USADA cannot assert control of a professional international sport and attempt to strip my seven Tour de France titles,” he said. “I know who won those seven Tours, my teammates know who won those seven Tours, and everyone I competed against knows who won those seven Tours.”

But sports lawyer Graeme Mew told CTVs Canada AM Friday morning that the anti-doping agency likely had the authority to do it.

“The international cycling union, which ultimately controls the sport of cycling, is a signatory to the world anti-doping code and the code is quite clear in what the consequences are in the case of an anti-doping rule violation,” Mew said. “By not contesting the charges the United States Anti-Doping Agency has effectively deemed that those charges have been made out.

“It’s hard to see – now that he has given up the fight – how he is going to avoid the consequences.”

Another sports expert told CTV that Armstrong’s move was the only way for him to avoid perjury and possible jail time that could have resulted if the case had gone forward.

“The U.S. Anti-Doping Agency was going to go forward with an investigation where Lance would have had to go on the record and say he hadn’t taken drugs and then he could have faced perjury charges,” Sports Business News publisher Howard Bloom said in appearance on Canada AM.

Bloom noted that all other members of Armstrong’s U.S. Postal Service team had admitted to taking drugs themselves and have said they saw Armstrong doping as well. He also noted the case of American track and field athlete Marion Jones, who spent time in jail after lying to a jury about taking performance-enhancing drugs.

“Lance is admitting guilt while avoiding perjury charges,” Bloom said. “I would expect that the Tour de France will follow through on what the United States Anti-Doping Association wants to do. I would also expect that the International Olympic Committee will strip Lance of his 2009 bronze medal that he won in the road cycling event in Sydney.”

Following the announcement Thursday night, public opinion appeared to be split on Armstrong in online forums, with some declaring the cancer-beating athlete a hero who has been unfairly smeared and others saying he is getting what he deserves.

Cycling world reacts

Former rivals also weighed in as the news spread Friday.

“I can’t help but feel a little bit like I’ve been duped,” Canadian Olympic cyclist Curt Harnett told CTV News Channel.  

Reached by phone at his home in Sezze, Italy, former Armstrong rival Filippo Simeoni told The Associated Press Armstrong’s career belongs to a period of rampant doping in cycling.

"That entire decade was one big bluff,” he said. “It leaves me a bit perplexed, because someone like him, with all the fame and popularity and millions of dollars he has should fight to the end if he's innocent.”

The International Cycling Union said it was still awaiting USADA's explanation before deciding whether it would take any action against Armstrong. The organizers of the Tour de France said it would wait to see what both USADA and the UCI do before commenting.

With files from the Associated Press