Lance Armstrong is banned from competitions sanctioned by Olympic governing bodies—part of his punishment for deciding last month not to fight charges that he engaged in doping as a professional cyclist. But Armstrong remains more than America's most famous endurance athlete. He is its only famous endurance athlete.

Lance Armstrong has decided not to contest charges by the United States Anti-Doping Agency and has been stripped of his seven Tour de France titles. WSJ's Reed Albergotti sits down with Wendy Bounds to discuss whether the most decorated rider in the history of cycling will now lose his legacy as well.

So when he seeks to compete in a triathlon—a sport whose popularity ranks far below that of, say, bass fishing—his magnetism makes an unthinkable question suddenly thinkable: Does the number of extra enrollments he brings to an event outweigh the loss of certification by USA Triathlon?

Faced with that very question this month was the Half Full Triathlon in Maryland. For two years running, it had boasted USAT certification, a distinction that lowers insurance rates while offering professionals a chance to boost their international rankings.

But when presented with a recent race request from Armstrong, Half Full for this year decided to sacrifice its USAT certification. And it paid off. After announcing last Thursday that Armstrong would participate in the Oct. 7 race, enrollment jumped 20%, said race executive Brian Satola.

That extra race revenue advances the Half Full mission of raising funds for cancer, as does Armstrong's cancer-battling track record, said Satola, adding that he would permanently trade USAT certification for Armstrong's participation. "Man, if we could get a multiyear commitment from Lance, I'd love it," he said, calling Armstrong "the world's best-known cancer survivor."  MORE