Katrina Matthews knew she was having a very good run at Ironman Tulsa on May 25, but in hindsight she thinks she could have gone faster.

The 30-year-old British pro got off the bike in third place, nearly 21 minutes behind Daniela Ryf and five minutes behind Skye Moench, but she hit the ground running out of T2 and immediately started closing those gaps. Ripping through the first 10K at about 6:18/mile pace, she could sense the built-up fatigue from the swim and the bike, but it wasn’t really showing up in her heartrate data.

By the time she reached the halfway point of the marathon in 1:24:20 (6:24/mi pace), she had already made up considerable time. When she caught and passed Moench at about 16.5 miles, she was only about 12 minutes behind Ryf and still running fast. She continued clicking off fast miles until a final hill in the closing miles made her work harder and slow a bit. She completed the 26.34-mile run in 2:49:49 and finished in 8:45:34, just 5:01 behind Ryf.

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“Yeah, I felt great. I was racing at a 165 heart rate for 90% of the race, which is very middle Zone 3 for me. That’s 10 beats below where it could have been,” said Mathews. Though she pushed it as hard as she could on the day, she believes she could still ultimately go faster.

"At the time, I probably couldn’t have gone much faster, but physiologically, on paper, there was capacity for that, so in the future, there’s reason to believe I could run a much faster marathon.”

In just her third Ironman, Matthews entered rarefied company with her sub-2:50 run split. While Kristin Moller’s 2:41:57 effort at IM UK in 2011 is widely considered the fastest women’s Ironman run split on record, only Chrissie Wellington (2:44:35, Challenge Roth in 2011; 2:48:54, Challenge Roth in 2010) and Mirinda Carfrae (2:49:06, IM Austria in 2016) have run faster than Matthews did that day in Tulsa.

With overcast skies, moderate temperatures, and some cool rain, that day in Tulsa proved to be a fast day for a lot of athletes. Patrick Lange left T2 12 seconds behind Daniel Baekkegard in second place, but then proceeded to run away from him and the rest of the field with blazing a 2:36:45 marathon split (5:57/mi pace) to take the win in 7:45:22. And while that gave him a 5:36 margin of victory, runner-up Jan Van Berkel (2:39:05) closed hard on the run to pass Baekkegard (2:44:34) late in the race, followed by fourth-place finisher Denis Chevrot (2:36:03), who was also flying.

Are the 2:40/2:55 marathon plateaus finally a thing of the past for Ironman elites? Maybe. Several factors have contributed to a handful of faster marathon splits in recent years and, with a surge of competitiveness after an awkward year without much racing, it could be a continuing trend.

Modern Times, Faster Times

Better and faster bike technology, enhanced aero positioning, improved science-based training, next-generation fueling drinks and gels, and, since 2018, running shoes enhanced with carbon plates in the midsoles, are some of the significant factors that have changed the game for running 26.2 miles (or 42.2 km) in a triathlon.

Does that mean we’ll see some super-fast run splits on Oct. 9 when the Ironman World Championship returns to Kona? Maybe. But maybe not.

“You can’t really compare a marathon in Tulsa to a marathon in Kona,” said six-time Ironman world champion Mark Allen. “To run that fast in Kona, there will have to be an awful lot of ideals that happen throughout the day.”

Allen set the standard in Kona and for the still-fledgling sport in 1989 when he ran an eye-popping 2:40:04 to outrun Dave Scott (2:41:03) in their famous Iron War duel. Although several athletes came close to breaking 2:40 in the ensuing years—Luc Van Lierde (2:41:48, 1996), Olivier Bernhard (2:41:57, 1999), Pete Jacobs (2:41:06, 2010), and Craig Alexander (2:41:59 2010)—it wasn’t until 2016 when Patrick Lange split a 2:39:45 while placing third overall that Allen’s time and the mythical barrier was finally surpassed. Lange broke 2:40 again the next year in Kona, albeit by a single second, when he scored his first win in Kona with an 8:01:40 effort.

“I was surprised that it didn’t get faster quicker in Kona and that it hasn’t gotten a lot faster,” said Allen, who had three other 2:42 marathon splits in Hawaii. “I always thought that on a good day I could run 2:35 there without it being a massive stretch, but of course I never did. There are so many factors that have to go right.”

It’s worthy to note that Van Lierde was credited with a 2:36:49 split at Ironman Europe (Challenge Roth) way back in 1997, so it’s not as if athletes haven’t been physically capable of running that fast.

Still, since Lange’s epic runs in 2016 and 2017, the 2:40 plateau for men has been broken numerous times at other races, though not in Kona. For women, sub-2:55 splits are becoming much more frequent. It’s still not easy to run fast at the end of an Ironman, but it’s not uncommon, either.

Why The Surge?

“I think a lot of the faster marathon times you’re seeing in Ironman-distance races outside of Hawaii are just a result of the overall level of competition getting higher,” Allen said. “The depth of the guys who are really good and the knowledge and coaching allows more people to optimize their training and fitness.”

The fastest Ironman run splits on record are from Matt Hanson (2:34:39) and Ivan Tutukin (2:35:19) at Ironman Texas in 2018. Although the run course was accurate that day in The Woodlands, Texas, the bike course was reduced to 110 miles for safety reasons, so no overall times were considered official and the run splits still carry an asterisk because of the truncated bike course.

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Aside from the quick splits of Chevrot and Lange at Tulsa earlier this year, Ben Hoffman split a 2:36:09 on an unseasonably cold day at Ironman Florida in 2019.

To him, Lange’s effort in Kona was the equivalent of Roger Bannister’s original sub-4-minute mile.

“I think that one of the biggest limiters as athletes is our minds,” Hoffman said. “But if you see someone else do it you say, ‘Why not me?’ And all of a sudden you see other people doing it or getting really close to it.”

But a fast run split is never just about what happens on the run, Hoffman says. Sure, wearing a pair of Nike Vaporfly Next% shoes—which he did in Florida in 2018 to average 5:58/mile—provides a notable boost of energy and, perhaps more importantly, helps offset built-up fatigue, running that fast demands favorable weather conditions, a near-perfect fueling strategy, and a solid and unwavering mental outlook, he says.

“I think when an athlete does that and breaks a barrier, it opens a door mentally for other people. Maybe you can’t even explain it, but whatever the combination of reasons that allowed them to achieve that performance on the day, it changes the outlook and expectation for everyone else.”

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“I think when an athlete does that and breaks a barrier, it opens a door mentally for other people."

For a brief period in the mid-1990s, Allen considered focusing only on the marathon so he could qualify for the U.S. Olympic Trials. He ran the 1994 Berlin Marathon hoping to run faster than the 2:22 qualifying time and was on pace through the halfway point.

“I was exactly where I wanted to be, feeling super relaxed,” Allen recalled. “And then I started into the second half and upped my pace and my legs just locked up. I made it to mile 18 and pulled the plug because I could barely even run. People asked me why didn’t you try to run marathons? It’s such a different event and it is a huge toll on your body to go that far and that fast.”

And yet, success in triathlon is about an optimal swim/bike/run combination, not just running as fast as possible.

At the most recent Ironman World Championship in 2019, Jan Frodeno turned in sparkling efforts on the swim (47:31) and bike (4:16:02) and then closed with his fastest marathon yet (2:42:43), en route to his third title in a course-record time (7:51:13). Hoffman was the next-fastest runner (2:43:08) that day and took fourth overall (8:02:52) in a time that would have won every race in Hawaii prior to 2017.

Meanwhile, Anne Haug set a women’s course record that day with a good swim (54:09), a good bike (4:50:17) and the fastest women’s run split in the race’s history (2:51:07). (She broke Mirinda Carfrae’s Kona run record of 2:52:09 from 2011.)

To Allen’s point, running fast in Kona is a different animal. The course is always hot, the conditions are always humid, and it’s often windy. Plus, the prestige of the race and the desire to perform well at the World Championship brings added pressure.

The day Hoffman ran a 2:36 in Florida, his bike split wasn’t anything special, even though his power data was OK. In retrospect, he thinks if he had ridden with 20-30 fewer watts, he might have run 2 or 3 minutes faster.

2:30 Or Faster?

“I would say that it’s absolutely possible,” Hoffman said. “I think it comes down to removing the barriers we often place for no good reason. I don’t know how long it would take or what will be required from a science and training standpoint to achieve that, but I absolutely believe that’s possible. It really just depends on the objective and whatever the day brings.”

Matthews, who ran 3:10, 2:57, and 2:49 in her first three Ironman races, plus a 3:06 in her July 4 training race at Ironman UK, believes she can continue to drop her running splits by way of continuing to improve her training, her fueling, her bike splits and trusting her workout and race data, not to mention keeping a positive attitude and believing she can run faster. She also might switch shoes from Nike Vaporfly Next% to the new ASICS Metaspeed Sky model.

Like everyone else, she’s mostly focused on competing well in Kona, not merely a fast run split.

“The best case scenario for me in Kona is that I come off the bike with the lead pack and there’s no threat of anyone running faster in front of me and there is only my own composure to run my own race that will see me win Kona,” Matthews said. “It would be an absolute gold star optimistic plan. It’s a bit optimistic, but who knows? Since I came into the sport five years ago, there has always been a phrase, ‘Bike for show, run for dough.’”