No one's going to sign up for a triathalon or long road race without training (except for Barney on "How I Met Your Mother," but that's OK because he's Doogie Howser and, you know, not real). But as triathletes watch their sport increase in popularity, there's also an increase in notoriety, injuries and, as the South Shore realized on Sunday, death.

A 38-year-old man died Sunday as he competed in Cohassett's inaugural triathalon. The man was swimming the first leg of the three-part race when he collapsed and then died. The fatality marked the third triathalon death this year, putting Massachusetts on an unenviable shortlist shared by Florida and Missouri. All three deaths occurred on the swimming leg of the race, the AP reports, and already marks an increase from last year's two triathalon fatalities.

Any guess as to what led to the 2006 fatalities? That's right - the swimming leg.

Triathalon photo by flicrk user MC Master Chef