But Menke says, once people are bitten by the triathlon bug, it becomes a way of life.

CNN: Everyday athletes embracing triathlon

"Lance Armstrong is currently still eligible to compete in all USA Triathlon-sanctioned races, with the exception of Ironman events as stated earlier by the World Triathlon Corporation, " said the body's communications director Chuck Menke.

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"We've experienced so much growth as an organization, with our annual membership over the last five years going from 50, 000 to 135, 000 annual members, " said Chuck Menke, director of marketing and communications at USA Triathlon.

CNN: Everyday athletes embracing triathlon

Menke says it's a combination of the Olympics -- triathlon made its debut in the 2000 Sydney games -- a growing group of middle-aged competitors looking to reclaim their athleticism, and a desire for fitness-conscious camaraderie.

CNN: Everyday athletes embracing triathlon

Sara Menke, the founder and chief executive of Premier, a boutique staffing firm in San Francisco, says having a job while looking for a job makes you that much more attractive to a potential employer.

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"I think it's become popular for people who have established themselves in their career, have a family, and who are fairly settled in their lives, professional and personal, and they're looking for a new challenge, " Menke said.

CNN: Everyday athletes embracing triathlon