Cardiac conditions that required surgery have forced into retirement two winners of the Ironman Triathlon World Championship.

WSJ: The Exercise Equivalent of a Cheeseburger?

Scheidies, who has completed the Ironman Triathlon, which includes a 2.4 mile swim, 112-mile bike ride and 26.2 mile marathon, registered for Detroit's Motor City Triathlon on June 17.

CNN: SHARE THIS

Mark Allen, the former All-American swimmer at UC San Diego who went on to win the Ironman Triathlon world title six times, says he finds that kind of fortitude amazing.

WSJ: Menu

"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.

CNN: SHARE THIS

The device also has got all the features of Timex's Ironman Triathlon sports watch.

FORBES: Ten O'Clock Tech: Webbing By Wrist

"I never got past being that little girl who thought she couldn't run, " she said, describing how she would watch Ironman competitions with amazement at the monster triathlon.

CNN: Virtual meetups spark real fitness

He is forgoing Ironman races to focus on short course racing again in hopes of qualifying for the 2012 Summer Olympics in London (an Olympic distance triathlon is about one-quarter the distance of an Ironman).

FORBES: The World's Greatest Athlete

Just days after New York City's first Ironman triathlon was held, it's unclear whether the event will take place again next year.

WSJ: City Could Lose the Ironman Race