The sub-8 Ironman is clearly too easy. Here’s how and when supercoach Matt Dixon predicts someone will go sub-7:30.

The sub-8 Ironman is clearly too easy. Here’s how and when supercoach Matt Dixon predicts someone will go sub-7:30.

Last month at Ironman Arizona Canada’s Lionel Sanders broke the record for the fastest Ironman-branded race ever, crossing the line in 7:44:29. Fellow Canadian Brent McMahon also shattered the 8-hour mark, finishing second in 7:50:15 (the fourth time he’s gone sub-8). Then last weekend, both New Zealand’s Terenzo Bozzone and the United States’ Andy Potts broke 8 hours at Ironman Western Australia. All of this came on the heels of a season where Germany’s Jan Frodeno broke the record for fastest iron-distance race, going 7:35:39 in July at Challenge Roth. According to Tri247.com’s detailed recordkeeping, that makes a total of 62 times that 38 athletes have gone sub-8 in an iron-distance race. And while the so-called 8-hour barrier has never been broken in Kona, it’s clearly not much of a barrier in general.

The sub-2 marathon, however, hasn’t happened yet, making it a thing of lore. Scores of articles are written every year debating if and when a human being will ever do it since the closest anyone’s ever run is nearly 3 minutes off. Entire books are devoted to the subject—it even has its own dedicated international research initiative with its own Twitter account. It’s an obsession with questioning our own physical and mental limitations we just can’t quit. So like true endurance wonks, we wanted to know what triathlon’s sub-2 hour marathon is—and when and who will break it. We turned to Matt Dixon, coach to multiple Ironman champions and owner of coaching company Purplepatch Fitness, for the answer. Here’s what he had to say:

The barrier in question is likely a 7:30 Ironman. If we dissect the swim, bike and run portion of the men’s racing, the clear area where men are ‘underperforming’ is the run. This is where athletes can make the biggest time gains.

The swim can only provide 1 to 2 minutes of performance gains, unless a short or current assisted swim is part of the course. Athletes already have high bike performances, but the run has a window of many minutes that are open for improvement. Why? Because of the way bike dynamics typically play out in races.

In men’s professional racing, the bike portion is seldom a steady-state time trial event. It typically includes massive oscillation in intensity, from ‘attacks’ from various competitors, as well as the yo-yo effect of riding in the legal pace line. This ends up having a massively corrosive effect on the ability to run very fast off the bike. If we add to this the typical heat and humidity that faces many athletes on the run position of the race, as well as the emotional barriers and framework of what fast Ironman running is, we see the biggest potential in the run.

To achieve a sub-7:30, you’d need about a 45 minute swim, a 4 to 4:05 bike, quick transitions, then a run under 2:30-2:35. It’s likely possible, but it would need to be set up on the right course. Something like Roth, of which the true distance is hotly debated, and with support.

Who’s going to do it and when?

Currently, Frodeno—who, in addition to being the world record holder, is the defending two-time Ironman world champion—is the obvious choice, but there are others with potential. It is too early to say ‘Oh the Brownlees/Gomez will kill it,’ but the short course racers will have an impact and ability to raise the bar of the sport generally. It only takes one, then within 2-3 years the level will rise much closer.