Home Running A Knowledge-Pushed Primer on the IAU 24-Hour World Championships – iRunFar

A Knowledge-Pushed Primer on the IAU 24-Hour World Championships – iRunFar

A Knowledge-Pushed Primer on the IAU 24-Hour World Championships – iRunFar


The 2023 IAU 24-Hour World Championships are taking place in Taipei on December 1 and a pair of. You would possibly say it’s the Olympics of 24-hour working: It attracts most of the finest runners on this self-discipline who race for his or her nationwide group, and it’s been 4 years because the final such championships (1).

The format and technique are easy in 24-hour races. You go so far as you may in 24 hours whereas working on a looped course. However, to borrow from a literary traditional from my childhood, “it’s too dangerous ‘easy’ and ‘simple’ don’t imply the identical factor (2).”

On this article, we’re 24-hour races. Consider this text as a primer on the race format, present information as of November 2023, and pacing methods so we’re all able to cheer on these high runners and our favourite nationwide groups.

Camille Herron - 2019 IAU 24-hour world champion - feature

Camille Herron on her strategy to setting a world report on the 2019 IAU 24-Hour World Championships. Photograph: U.S. Nationwide 24 Hour Operating Group

[Editor’s Note: We kindly remind readers that the Running the Numbers column is a just-for-fun analysis. While we always endeavor to analyze accurately, we limit the scope of each article in order to make the work doable for author Mallory Richard, and the results digestible for readers like you.]

The Fundamentals on the 2023 IAU 24-Hour World Championships

The 2023 occasion will begin at 10 a.m. native time on December 1. The course has one thing of a lollipop form, which every lap measuring 2 kilometers (1.24 miles.)

Based on the checklist of entrants the Worldwide Affiliation of Ultrarunners (IAU) printed on November 8, 2023, the world championships will embody 262 runners from 41 nations. Nations with at the least three runners competing in a single gender class are eligible for the group occasion. The scores of every nation’s three finest performers might be used to find out the group’s rating. A concurrent particular person competitors will acknowledge one of the best particular person racers.

The races are sure to be thrilling. On the 2019 occasion in Albi, France, Camille Herron set a brand new world report and Aleksandr Sorokin’s profitable consequence was additionally a Lithuanian nationwide finest. In lots of respects, circumstances in Taipei might be conducive to robust performances. Every lap in Taipei covers 2k in comparison with the 1.5k loop on the earlier world championships, so runners could face much less congestion.

Taipei provides a usually heat and humid local weather, which is much less conducive to quick working. That stated, a passing climate system appears to offer below-average temperatures, an overcast sky, and a few rain this weekend, what may make for fairly glorious working.

Earlier this week, we printed an article concerning the historical past and evolution of the 24-hour world report, in the event you’re in search of much more data on this race format.

Methods for 24-Hour Operating

Like so many aggressive ultramarathons, attrition represents a serious wildcard on the IAU 24-Hour World Championships. Camille Herron described hours 14 to 18 because the interval when runners are more than likely to come across points. At that time, they’ve logged many miles on the identical flat, unforgiving terrain through which they repeatedly use the identical muscle teams and – if issues are going effectively – minimal fluctuations to their tempo.

The hairpin flip on the finish of the lollipop-shaped course will additional exacerbate the pressure to their ankles, knees, and hips. Overuse accidents are a really actual menace. Continuous working takes a toll on their gastrointestinal methods. Round hour 14, the solar goes down, and so does the temperature. Athletes will really feel the affect of sleep deprivation.

Mixed, these components imply that 24-hour races are extremely fascinating to comply with, regardless of their on-paper simplicity. Like in different aggressive ultramarathons, each runner at this occasion might want to continuously consider their race plan and execution and make changes in actual time, based mostly on their efficiency targets, private health, and their evaluation of the competitors. Some runners will begin out too aggressively, some runners will deliberately begin at a barely quicker tempo than they anticipate to complete, and a few runners will mete out their vitality to stay robust within the ultimate 10 hours — and to presumably even muster the power for surges.

Aleksandr Sorokin - 2022 IAU 24 Hour European Championships winner

Aleksandr Sorokin, after profitable the 2022 IAU 24-Hour European Championships, in a brand new world report. Picture: Marius Antanaitis display seize from race video

Knowledge on 24-Hour Pacing and Attrition

Camille Herron supplied iRunFar with a replica of the splits from the 2019 IAU 24-Hour World Championships. The IAU shared its splits from the 2022 24-Hour European Championships. We used these datasets to create the stability of this text.

Each datasets assist Herron’s remark that an unvarying (or barely various) stride on flat terrain in a aggressive atmosphere results in some blowups. 1 / 4 of the athletes from the European championships dataset — 25% of the ladies and 25% of the boys — had stopped working earlier than the 23-hour mark.

Running the Numbers - Attrition Rate 24-Hour Runners

Desk exhibiting attrition charges within the 2022 24-Hour European Championships

We see the toll in runners’ splits as effectively. Runners usually begin out at constant paces, with modest modifications from one lap to the following within the earliest hours of the race. Because the race progresses, even high performers can encounter points that require them to decelerate and troubleshoot. Within the 2019 IAU 24-Hour World Championships, the primary “lap” was a partial lap of roughly 0.1 kilometers, so I mixed the primary and second laps. Consequently, the next charts for the 2019 world championships could look as if many athletes began sluggish earlier than settling right into a quicker tempo on subsequent laps, however they definitely didn’t.

Lap Paces for Teams of Runners

For the charts under, I calculated the typical tempo for every lap for every of the next teams for every gender:

  • The ten contributors who ran the farthest.
  • The ten contributors who lined the least distance amongst those that ran the total 24 hours.
  • The ten contributors whose ultimate distance outcomes have been within the very center between the 2 teams above (referred to as mid-pack within the chart under.)

I solely confirmed every group’s common tempo as much as the farthest lap when the group nonetheless had 10 runners in that cohort.

2019 IAU 24-Hour World Championships Paces by Group

2019 IAU 24-Hour World Championships Paces by Group

Chart illustrating the pacing of various teams of runners all through the 2019 IAU 24-Hour World Championships.

2022 24-Hour European Championships Paces by Group

2022 24-Hour European Championships Paces by Group

Chart illustrating the pacing of various teams of runners all through the 2022 24-Hour European Championships.

You may see that in every race and for every group, the typical tempo per lap tended to extend because the race progressed, however the high women and men slowed the least. That is value noting for American followers, as a result of Nick Coury ran a detrimental cut up when he set a brand new American report in 2021, doing it so masterfully that you simply’d be forgiven for pondering that’s widespread in these races.

The chart above means that, when thought of as teams, the top-10 males and the top-10 girls had essentially the most even and constant pacing of the six teams proven. This speaks volumes about their health and race execution. It doesn’t, nevertheless, imply the highest runners had excellent races. Because the charts under point out, the highest runners engaged in loads of troubleshooting.

Nick Coury - 2013 World 24 Hour Team

Nick Coury (entrance left) with the remainder of the U.S. 24-hour group on the 2013 IAU 24-Hour World Championships. Photograph courtesy of Nick Coury.

The charts under present the tempo per lap for every of the top-five runners within the girls’s and males’s particular person races. I solely included the top-five runners in these charts (versus 10) to maintain the charts legible.

Each time you see a dramatic spike in one of many traces, that represents a lap that was considerably slower than the laps earlier than and after. This implies the runner in query both walked a lap, or stopped working to take care of themselves ultimately.

As somebody with restricted private expertise and nil success with fixed-time races, I used to be shocked to understand one of the best runners weren’t resistant to mid-race points. The charts under gave me a deeper appreciation of what they’re undertaking — they could be stopping to alter layers, get medical therapy, puke, or regroup on the bathroom similar to the remainder of us. However after they begin working once more, they discover a strategy to get again to the quick working they have been managing earlier than. It’s not excellent execution; it’s masterful problem-solving.

The diploma to which this happens is revealed in a robust instance from Camille Herron — in response to her, she spent greater than 56 minutes of the 24-hour race window on the 2019 world championships within the assist station or bathrooms. Her race included medical/physiotherapy care, puking, and taking the time to devour the fitting fuels to settle her abdomen. Whereas any a type of points would have justified quitting for loads of runners, Herron was nonetheless on target within the ultimate minute of the occasion, like most of the different high finishers. The hassle bought her a world report.

Lap Paces for the High 5 Girls on the 2019 IAU 24-Hour World Championships

Running the Numbers - 2019 24-Hour World Championships Top 5 Women - pacing

Chart illustrating the pacing for every lap of the top-five girls on the 2019 IAU 24-Hour World Championships.

Lap Paces for the High 5 Males on the 2019 IAU 24-Hour World Championships

2019 24-Hour World Championships Top 5 Men - pacing

Chart illustrating the pacing for every lap of the top-five males on the 2019 IAU 24-Hour World Championships.

Appreciating the Outcomes

Now that we’ve mentioned simply how difficult this race format is and what number of issues can go fallacious, let’s discuss what these athletes accomplish amidst these challenges. It’s not at all times simple to understand the importance of the outcomes on the IAU 24-Hour World Championships, as a result of an distinctive runner’s common tempo might be one which many ultrarunners can maintain for at the least a number of miles. Just like a yard extremely, one of the best runners are working with paces and energy ranges our minds can grasp, however proceed to rack up beautiful mileage totals.

The histograms under present the distribution of outcomes inside the males’s and girls’s particular person races. As you may see, the 2019 world championships was one in every of only a few 24-hour races the place the overwhelming majority of runners lined at the least 100 miles (160k) within the time out there. With the game of ultrarunning gaining extra recognition over the previous 4 years, will probably be thrilling to see how the outcomes on the 2023 race examine.

Distribution of Males’s Outcomes on the 2019 IAU 24-Hour World Championships

2019 24-Hour World Championships Men's Results Distribution Chart

The chart above reveals that almost all of contributors within the males’s race totaled over 100 miles in 24 hours. The supply for this knowledge is the outcomes from the “UltraRunning” journal web site, supplemented by the IAU’s outcomes checklist (as a result of the UltraRunning outcomes omitted the 2 finishers who totaled fewer than 26 miles.)

Distribution of Girls’s Outcomes on the 2019 IAU 24-Hour World Championships

2019 24-Hour World Championships Women's Results Distribution Chart

The chart above reveals that almost all of contributors within the girls’s race totaled over 100 miles in 24 hours. The supply for this knowledge is the outcomes from the “UltraRunning” journal web site, supplemented by the IAU’s outcomes checklist (as a result of the UltraRunning outcomes omitted the finisher who totaled fewer than 26 miles.)

The Desert Solstice Monitor Invitational is an annual 24-hour monitor race held in Arizona. As an invitation-only occasion, entry is reserved for elite athletes who meet the race’s qualifying requirements. As a result of ultramarathons are unpredictable, most of the athletes who achieve entry don’t meet or exceed the race efficiency that allowed them to qualify for the occasion. It’s a reminder that, as for the world championships, a foul day is a really distinct risk for any elite athlete beginning a 24-hour race.

Nonetheless, Desert Solstice can be a helpful benchmark for the world championships as a result of its qualifying requirements assist us recognize the variety of elite performances we see in a single race (the 2019 IAU 24-Hour World Championships) and provides us a way of what to anticipate for 2023.

% of men and women in the 2019 24-H WC who achieved Desert Solstice qualification standard

Desk exhibiting the share of women and men within the 2019 IAU 24-Hour World Championships who achieved the Desert Solstice Monitor Invitational qualification customary.

Of word, the qualification requirements for the world championships range vastly from nation to nation. In Canada, for instance, an athlete should have lined a minimal of 180k in a 24-hour race to qualify for the ladies’s group, however athletes from different nations have gained entry with private bests of lower than 100 miles.

The idea of working for twenty-four hours straight is acquainted to many people mid-pack runners as a result of we’ve got taken 24 or extra hours to complete a 100 miler. To fathom the enormity of the problem for opponents within the IAU 24-Hour World Championships, it may be useful to contemplate their 100-mile splits, after which take into consideration how they maintain working for hours after that.

For instance, Aleksandr Sorokin accomplished his one hundred and fifth lap on the 2019 world championships with 11:46:57 elapsed. That meant he had lined 160.3k, or simply over 100 miles. He then almost repeated that feat, ending his 209th lap with 23:56:29 elapsed and profitable the boys’s particular person race.

Equally, Camille Herron calculated her 100-mile cut up as 13:17:25, which was even quicker than Marisa Lizak’s profitable time at Desert Solstice that very same yr, which “UltraRunning” journal acknowledged because the quickest 100-mile run of any girl on North American soil in 2019.

Closing Ideas

As at all times, that is one thing of an armchair evaluation, as a result of it attracts on incomplete splits from a pair races. And but, there’s rather a lot to dig into right here, particularly for ultrarunning followers who’re much less aware of fixed-time races.

We’ve tried to quantify the competitiveness of the upcoming race and the challenges of acquiring a aggressive consequence on this self-discipline. If you end up ready to comply with the occasion in real-time on race day, you’ll be capable to recognize the explanation why, as Camille Herron identified, the occasion will get actually attention-grabbing round hour 14.

Name for Feedback

  • How do you assume the extent of competitors within the 2023 IAU 24-Hour World Championships particular person race will examine to 2019?
  • Which athletes will you be following this yr?
  • Whether or not from your individual private expertise or evaluation, do you have got any insights on efficient pacing methods in fixed-time ultras?


  1. I really feel compelled to level on the market’s some nuance on this assertion. After I say the race will appeal to one of the best athletes within the self-discipline, I don’t need this to be misinterpret as the entire finest athletes within the self-discipline. As has been lined elsewhere, participation within the IAU 24-Hour World Championships is mostly self-funded by the athletes. They could obtain monetary assist from their nationwide governing physique, however the quantity of that funding varies by nation. Moreover, just like the Path World Championships, some high athletes are unable to attend due to different races of their schedule. For instance, Amanda Nelson presently holds the Canadian girls’s report for twenty-four hours, however is recovering from working 57 yards on the 2023 Massive Canine’s Yard Extremely in late October. Briefly, followers of the game could have a lot of elite athletes to cheer for on the IAU 24-Hour World Championships in Taipei, and their performances there’ll encourage their friends in addition to us common people.
  2. The literary traditional is Steve Perry’s 1996 novel, “Shadows of the Empire.” The novel expanded the storytelling of the Star Wars galaxy by recounting the adventures of Luke Skywalker, Leia Organa, Lando Calrissian, Chewbacca, R2D2, and C3PO between the conclusion of “The Empire Strikes Again” and the opening scene of “Return of the Jedi.” The novel was a part of a multimedia launch that additionally included a online game and motion figures. “Shadows of the Empire” has been designated a part of the “Star Wars Legends,” because the Star Wars movies numbered Episodes I-VI are the one merchandise launched previous to April 25, 2014, which are thought of a part of the official Star Wars canon. Regardless, I consider “Shadows of the Empire” has the facility to resonate with path runners and ultrarunners in lots of refined and profound methods, not least of which is Perry’s skill to mix humor and poetry. Who hasn’t had a race the place it felt like “the nerf waste hit the ventilator shaft,” or struggled on a technical ridgeline and thought to themselves, “It could be an extended afternoon. Or a brief one…”



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