During long training rides, Levi Leipheimer would trade secrets with his friends and foes about what did and didn't work when it came to EPO, blood transfusions and other ways of eking out the last ounces of speed and stamina they needed to stay at the top of their grueling sport.

One thing virtually all the riders agreed on: They wished they didn't have to break the rules, but felt they had no choice, Leipheimer said at a symposium last weekend.

Leipheimer, one of the key witnesses in the doping case against his former teammate, Lance Armstrong, was the headliner at a U.S. Anti-Doping Agency science symposium held last weekend in Atlanta.

The event was closed to the media.

USADA CEO Travis Tygart told the Associated Press about details of Leipheimer's talk, which he said included the cyclist's discussion about "the informal and formal consequences of doping and how that affects decision making."

"What struck me is he said, in his mind, this is an historical moment for the sport," Tygart said. "He said it wasn't just about a few athletes getting sanctions, it's about trying to change the culture and learn from the culture that was there at the time."

The USADA report, released last week, uses testimony from Leipheimer and 10 other Armstrong teammates to paint in vivid detail the dope-or-else attitude that ruled on Armstrong's teams as he won seven straight Tour de France titles from 1999-2005.

USADA ordered all those titles stripped and sent its report, with more than 1,000 pages of evidence, to the International Cycling Union, which is deciding whether it wants to appeal the case to the Court of Arbitration for Sport.

Leipheimer spoke to an audience of more than 100 people — including scientists and officials from anti-doping agencies around the world.

Daniel Eichner, the former science director at USADA who now heads the Sports Medicine Research and Testing Laboratory in Salt Lake City, said receiving first-hand information from a key player in a major doping scheme was valuable.

"Traditionally, we have hardcore science meetings where we talk about the best mass spectrometer and how to detect these substances," Eichner said. "To get him to come in and truthfully talk about his program, it was powerful. This one was more about deterrence, how our job is not to catch but to deter."

Eichner said Leipheimer's stories about the discussions riders had during their four- and five-hour training rides hit home the hardest.

"The message was that none of the riders wanted to do it, but they thought they had to," Eichner said. "Once they became pros, they were really given no choice."

Armstrong has consistently pointed to the hundreds of drug tests that he passed as proof of his innocence during his run of Tour titles. USADA combined scientific data with the testimony of 26 witnesses — including 11 Armstrong teammates — to produce a record of what Tygart called "the most sophisticated, professionalized and successful doping program that sport has ever seen."

Tygart said Leipheimer, who is serving a reduced, six-month suspension for his doping violations, came voluntarily to the Atlanta symposium.