The "new breed", Kris Gemmell calls them: they are triathletes, typified by the Brownlee brothers of Britain, who have taken the sport to a new level with their running speed.
It's still a sport of three disciplines - swim-bike-run - but athletes such as Jonathan and Alistair Brownlee are taking the 10km final leg to a new level. The question now is: just how fast can they go?
Olympic gold medallist and former world champion Alistair, not at yesterday's ITU final of the world championship in Auckland after a recent appendix operation, won in London with a 10km time of 29 minutes seven seconds. And that with his body already fatigued by a 1500m swim and 40km cycle leg.
To put his running time into perspective, Mo Farah won the Olympic 10,000m track gold medal in 27m 30s.
Yesterday's split times in downtown Auckland obviously weren't going to be as impressive, given the hilly course and torrential rain, but the run was still extremely fast as Gemmell quickly found out. His 58s lead off the bike was swallowed up at the end of the first 2.5km lap.