LOS ANGELES: Nike, a company that identifies itself with sporting excellence, had no choice but to cut ties with Lance Armstrong in the face of a damning doping report, one sports business expert said on Wednesday.

David Carter, a sports business professor at the University of Southern California and executive director of USC’s Sports Business Institute, said that Nike could no longer afford to stand by Armstrong as it had other disgraced icons.

“I think because his indiscretion cut to the very heart of competition in sport, if he lacks that kind of integrity there’s no way a company like Nike can tolerate that,” Carter said.

Nike stuck with golf superstar Tiger Woods even as other sponsors dumped him in 2009 in the midst of a sex scandal that wrecked his marriage.

Nike also supported NBA superstar Kobe Bryant when he faced a sexual assault charge in 2003, which was eventually dropped.

NFL quarterback Michael Vick, vilified for his role in a dog-fighting ring, was dropped by Nike but resigned after serving a prison sentence and resuming his gridiron career.

“The other guys’ problems were off the field of play,” Carter said.

Nike had continued to support Armstrong in August, when the US Anti-Doping Agency (Usada) announced it was banning the Texan for life and stripping him of his seven Tour de France titles for doping infractions.

But last week, Usada issued a massive report detailing the basis for its sanctions, including sworn statements from 26 witnesses, 11 of them former Armstrong teammates who put him at the center of a sophisticated doping program while with the US Postal Service team.

“Due to the seemingly insurmountable evidence that Lance Armstrong participated in doping and misled Nike for more than a decade, it is with great sadness that we have terminated our contract with him,” Nike said in a statement, adding that the company would continue to support Livestrong, the charity the cancer survivor created to help those coping with the disease.

Armstrong stepped down as chairman of the foundation on Wednesday, a move that Carter said was necessary if the charity was to continue its mission.

“Obviously, Livestrong will always be associated with Lance Armstrong, but he can’t be the face of it,” Carter said. “He understands that.”

Daniel Borochoff, president of the non-profit watchdog CharityWatch, agreed that Livestrong’s future would depend on the organization distancing itself from the scandal.

“What the organization needs to do is separate Lance Armstrong and all the charges of doping against him from the organization, and this helps to do it,” he said. “The quicker they move away from him the better off they’ll be.”

Borochoff’s Chicago-based organization ranks Livestrong among its list of top-rated charities, based on criteria such as what percentage of the budget goes to programs.

“A lot of charities started by sports stars don’t amount to much . . . they can be poorly run—this is a good one. This is a good organization,” Borochoff said.

However, the fact that it is so closely identified with Armstrong could put off potential donors, even though Usada’s sanctions in August actually brought a spike in contributions.

“When a scandal happens, reality starts to seep in later with some of these constant reports and 1,000 pages of documents and so forth— people start to realize there is a problem here even if it was somebody’s hero,” Borochoff said.

Carter noted that a surprising number of disgraced athletes manage to rehabilitate themselves in the eyes of fans and sponsors.

Armstrong might be different, not only because he was already retired from top-flight cycling when he was banned but also because he has never admitted any wrongdoing.

“The only way they come back is when they take personal responsibility and accountability for what they’ve done,” Carter said.

“He has not taken responsibility.”