In 2011, researchers in Switzerland came up with a formula to predict a person’s Ironman race time. By plugging in variables such as an athlete’s Olympic triathlon finishing time and marathon PR, one could come up with a rough approximation of their finishing time in an Iron-distance race. In 2015, those same researchers conducted a meta-analysis of 76 studies on Ironman racing, trying to identify common features of the best iron-distance racers. It’s all part of a quest to find a definitive answer to the question, “What makes a good Ironman triathlete?”

It’s likely Tokyo individual triathlon gold medalists Flora Duffy and Kristian Blummenfelt are asking themselves that same question right now. Fresh off their wins in Tokyo, the Olympic champions have been invited to participate in October’s Ironman World Championship in Kona. Blummenfelt has already confirmed that he’s in – prior to the Olympics, he planned to race his first first-ever Ironman triathlon in Frankfurt on August 14 (three weeks after racing in Tokyo) with a goal of qualifying for Kona. Now, he can skip that race and instead head straight to the Big Island. Duffy has yet to commit to the event, though she is no stranger to ambitious goals: In 2016, Duffy became the only person to win three triathlon world titles in the same year, claiming the WTS, ITU Cross Triathlon, and XTERRA titles in close succession.

But neither have raced an iron-distance race of any kind before, much less against the top long-course athletes in the world on one of the most grueling courses in the sport. Could their success at the Olympics roll over to their debut Ironman (in Kona, of all places)? Only two people have won an Olympic medal and an Ironman world title, though in separate years: Jan Frodeno and Michellie Jones. The most recent medalist to take a stab at Kona was two-time gold medalist Alistair Brownlee, who flamed out spectacularly in what he called “the worst two hours of my life.” To date, no one has won the Olympics and Kona in the same year.

“I’ll start by saying that it would be very, very difficult for an athlete to pull off the Olympic/Kona double. The training, nutrition, and experience level that it takes to win each are quite different,” said Ryan Bolton, who represented the United States in tri at the 2000 Olympic Games and who is currently coaching multiple Ironman champions—including Ben Hoffmann.

Siri Lindley agrees it’s difficult, but is more optimistic about the odds. The 2000 Olympic alternate has coached both Olympic medalists and Ironman World Champions, and says there are multiple examples of how short-course speed parlays nicely into Ironman triathlon.

“Look at Jan Frodeno: gold medalist, ITU star, comes into Ironman and is obviously extraordinary,” Lindley said. “Look at Olympic silver medalist Lisa Norden. There are so many examples of short-course ITU athletes, Olympic athletes that come to Ironman and do amazingly well.”

So how can Blummenfelt and Duffy become a Frodeno or Norden – or better yet, beat them in Kona this year? Lots of factors come into play.

Factor 1: Timing

Though Bolton doesn’t doubt the fitness and ability of either Blummenfelt or Duffy, he does question the abbreviated timeline for preparation.

“To be successful in Kona, they will have to shift their training immediately to properly prepare them for a successful Kona bid.”

Lindley agrees the abbreviated timeline is cause for concern. The adrenaline they have from their Tokyo wins can fuel panic training, which would be a detriment. “[Duffy and Blummenfelt] may think they need to make up for lost time in long, long rides and long, long runs,” Lindley said. “But I think the more critical factor is figuring out a nutrition and hydration plan, not overtraining, trying to catch up, thinking they need to do a ton of long, long, long sessions.”

Factor 2: Base Training

Neither Blummenfelt nor Duffy are strangers to hard work. Blummenfelt, in particular, is known for high-volume training. In a typical year, he trains about 1,370 hours, swimming the distance from Norway to Greenland (2,400km), running from New York to Vancouver (5,000km), and cycling from Oslo to Sydney (16,000km), much of it at threshold intensity.

“Blummenfelt is a very strong athlete that puts in higher volume training,” Bolton said. “While I doubt he’s been putting in Ironman-specific training in the buildup to the Olympics, the type of training that he historically does could easily transition to Ironman training. He has the foundation that would be necessary to build on, giving him an advantage over other Olympic-distance athletes who do lower volume/higher intensity work.”

Duffy may not rack up as much volume in her training, and that could be an advantage, said Lindley. “These athletes haven’t destroyed their bodies with the long-distance stuff year after year. I’ll never forget Rinny [three-time Ironman World Champion Mirinda Carfrae] in her first year at Kona.”

“When we showed up in 2009, she’d never run a marathon in her life. She had never run over 16 miles in her long training runs, yet she came in and had the fastest women’s run split of the day, and ended up getting the course record a couple years later.”

“She had the advantage of bringing that short-course speed and strength, plus the grit, determination, and passion that came with it.”

Factor 3: The Newbie Issue

“It’s very rare for a person to win Kona their first time there. It’s only happened a handful of times,” Bolton said. “Without a previous Ironman under the belt, Duffy or Blummenfelt really don’t know how the body will respond to the distance, the heat, the conditions, and the competition. If they don’t race smart on the bike, they’ll really pay on the run. Understanding that course, the conditions, and how the race plays out differently from other Ironman races is very, very important.”

This is particularly true in 2021, when the field will be made up of mostly veterans with extensive knowledge of the course and how to race it. In addition to three-time Kona champ Frodeno (who just set a world record for fastest Iron-distance time), Blummenfelt will be racing against 2018 Kona champ Patrick Lange and 2019 runner-up Tim O’Donnell, along with favorites like Braden Currie, Ben Hoffman, and Andreas Dreitz.

If she chooses to race, Duffy will face a similarly stacked field in Kona, with four-time Ironman World Champion Daniela Ryf, 2019 champion Anne Haug, and Kona podium finishers like Lucy Charles-Barclay and Sarah Crowley.

Factor 4: Age and Experience

Even though both athletes lack experience in Kona, that doesn’t mean they’re coming into the race completely green. The ability to perform under pressure – especially in the midst of a spectacle like the Olympics or Kona – is something Duffy, in particular, has demonstrated time and again.

“The Olympics is the grandest stage,” Lindley said. “Being able to deal with that kind of pressure, which they obviously handled beautifully in Tokyo, will serve them well at another grand stage, which Is the Ironman World Championship.”

“Flora has been in the sport for a long time and is more in the age range of successful Ironman athletes,” Bolton said.

"Flora is also very calculated, and I'm confident that she’ll analyze all of the scenarios prior to doing the race to make sure she has all of her I's dotted and T's crossed.”

Though he has yet to rack up a lengthy list of wins like Duffy, Blummenfelt has also shown that he is clutch in intense situations. In addition to his win in Tokyo, Blummenfelt has dug deep to win tough races at the ITU World Final and as part of a Norwegian podium sweep at the Bermuda ITU World Triathlon Series.

Factor 5: Guts + Grit

What Duffy and Blummenfelt lack in experience, they make up for in grit. “It may be [Blummenfelt’s] first Ironman race, but I think that with the kind of training he’s had to put in and the kind of work he’s had to do – in all aspects, not just physically but emotionally and mentally, spiritually – he can pull off an amazing race,” Lindley said. “I would say the same goes for Flora. She is fierce. She has that grit, that determination, that passion and ability.”

“Kona takes guts, and both athletes have plenty of those,” said Bolton, who points out this could also be a liability: “Racing within yourself and focusing more on internal than external cues is also important in this race. Blummenfelt is used to racing aggressively and reactively. If you do that in Kona, you’ll likely be in a world of hurt by mile 10 of the run.”

The Bottom Line

Though the Olympics and Kona both fall under the umbrella of triathlon, they’re entirely different races with entirely different strategies. Dominance at short-course triathlon can be a good foundation for long-course success, but performing well at Ironman – especially at the World Championship level – usually requires some degree of experience.

Neither Blummenfelt or Duffy have this experience on their side, but that doesn’t mean they’re doomed to fail should they toe the start line at Kona. “The course, conditions, and dynamics of this race are very important to understand and prepare for,” Bolton said. “For either to be successful they will have to train correctly, stay healthy, and most importantly, take an academic approach to what it takes to win in Kona.”

Hypothetical Finishing Times for Blummenfelt and Duffy

How might Blummenfelt or Duffy actually do at Kona? Using their Olympic finishing times and a reasonable prediction for marathon time (to date, there is no marathon finishing time for either athlete) in the Switzerland formula for Ironman prediction time, an approximate guess could be as follows:

MEN: Ironman race time (minutes) = 152.1 minutes + 1.964 × personal best time in Olympic-distance triathlon (minutes) + 1.332 × personal best time in a marathon (minutes)

Predicted Blummenfelt time in Kona: 8:46:48

WOMEN: Ironman race time (minutes) = 186.3 minutes + 1.595 × personal best time in Olympic-distance triathlon (minutes) + 1.318 × personal best time in a marathon (minutes)

Predicted Duffy time in Kona: 9:06:18

It’s important to note these estimates are just that – estimates. There’s no way to know for certain how things will play out until a race actually takes place (if it even does).