Augusta, Ga. ? Lance Armstrong is retiring after this year’s Tour de France, ending a cycling career in which he inspired millions by overcoming testicular cancer to win his sport’s signature event a record six straight times.

Armstrong said he remains “fully committed” to winning his seventh straight Tour de France this year and is driven “by that dream to go out on top. That’s a big deal to me.”

“It will be the last one, win or lose,” the 33-year-old Texan said at a news conference Monday.

The Tour de France ends on July 24. Armstrong said he began thinking about retirement after his victory last year. Spending a month away from his children recently helped to seal the decision.

“That was much more difficult that it had been before,” he said. “They are at a stage now where they change daily, if not hourly. … It’s time for me to not miss key moments in their lives.”

He said that while watching a recent cycling race on TV with his girlfriend, musician Sheryl Crow, he was so stirred by the competition, “I couldn’t sit down the entire race.”

Crow then challenged him on his retirement decision.

“She said ‘Look at you. You can’t even sit down. How are you going to retire?”‘ Armstrong said. “It’s a great question. I have to tell you I am 100 percent committed and the decision is final.”

Monday’s announcement came on the eve of Armstrong’s defense of his Tour of Georgia championship. The six-day, 648-mile event he uses as a training tool for the Tour de France begins today in Augusta.

Armstrong said the Georgia race could be his last professional competition in America, though he left open the possibility of racing in May at another practice event before the Tour de France.

Cyclist Lance Armstrong contemplates a question from a reporter Monday during a news conference in Augusta, Ga., where he announced he will retire from the sport after this year's Tour de France.