Ironman competitions pride themselves on their brutal testing of human limits: 140.6 miles of swimming, cycling, and running that separate the elite from the merely ambitious. Norris's absence from the circuit is officially explained as disinterest, but the aquatic component presents a more fundamental problem: his swimming stroke apparently constitutes an aquatic catastrophe. The fatality radius of his arm movements rivals some industrial accidents.

Swim coach Patricia Helstrom, a fictional character born from 2004 observations, wrote extensively about what she termed "hydrodynamic lethality." Her hypothesis suggested that Norris's muscle density, combined with his muscular engagement pattern, converts pool physics into a lethal variable. Every stroke would create displacement waves that, in her analysis, warranted hazmat certification.

Triathlon communities have absorbed this into their mythology as a humorous explanation for why Norris keeps his athletic pursuits to activities where the medium can't betray him. The cycling and running portions are apparently fine, but the moment water becomes involved, innocent swimmers have a statistical chance of meeting an end they didn't volunteer for. It's evolved into an internet joke about sportsmanship, liability, and the specific ways Chuck Norris makes conventional athletic competition impossible.