Maurten spent months working with Sawe and other runners getting their gut capacity trained so they could absorb and burn 100 carbs per hour[0][1]
> The Maurten research team was embedded with Sawe’s team in Kenya for 32 days across six trips between last and this April. They were training his gut to absorb that load by mimicking race-day protocol in training. The hydrogel technology they have developed over the past 10 years now allows athletes to absorb 90–120 grams of carbs per hour without GI distress.
Second is the shoes. Adidas Adizero weigh 96 grams[2] with new foam tech and new carbon plates
Nike and INEOS spent millions over years to get Kipchoge to a sub-2 in artificial conditions, and now the elite end of the field are knocking that barrier out in race conditions. Unreal.
Running tech and training have been revolutionized in the past few years.
[0] https://marathonhandbook.com/sebastian-sawe-arrives-in-londo...
[1] https://www.instagram.com/p/DXmvAUvkWaq/
[2] https://www.runnersworld.com/uk/gear/shoes/a71129333/sabasti...
edit: correct :s/calories/carbs thanks
burning a hundred calories an hour is trivial. Most people will burn 100 calories per mile when walking or running, and more if moving as fast as these athletes, and many, many humans can do this for far, far longer than 2 hours.
It's the absorbtion that's the challenge. Maurten is not somehow alone in the particular stuff they've developed - ultra runners are generally shifting up into the 90-120 gram/hr range (or beyond!), using a variety of different companies' products. The gut training protocols for this are widely discussed in the world of running for almost any distance above a half marathon.
GP left out the units but is clearly talking about grams ("absorb ... 100 carbs per hour"), not calories (no one needs training to absorb 25g/hr). Carbs are 4 kcal/g. 100g of carb (400 kcal) an hour isn't replacement level for even casual athletic efforts, but it does mitigate the loss of glycogen in muscle somewhat.
> Even if you can absorb 120 grams per hour, it might not make you faster. In Podlogar’s study, cyclists burned more exogenous carbs when they consumed 120 rather than 90 grams per hour, but that didn’t reduce their rate of endogenous carb-burning—that is, they were still depleting the glycogen stores in their muscles just as quickly.
https://www.outsideonline.com/health/training-performance/en...
Is that all the science to it?
Gut training is consuming large amounts of carbohydrate (preferably in the same form you intend to use when racing), yes.
It’s also about the methods of achieving that under stress without spewing it all back up. Ironman athletes would stuff their faces on the bike under the assumption that this volume of carb absorption wasn’t possible while running.
Some of the challenge in research will come from competitors not wanting to publish results to maintain an edge. It is mitigated by the visual of the race by (you can see athletes pounding carbs), as well as the nutrition companies wanting to sell more product. This will cause them to publish some information to convince us amateurs to quadruple our purchase volume ;-)
The race to tolerate lots of carbs is usually something you think of in 8 hour Ironmans. The good part is you can do most of it on the bike, which is much easier to eat as you go. As far as I know, many elite runners were doing like 50% water, 50% sports drink and consuming way under 100g.
So ~2800 calories of carbs with some fat being burned.
Running will absolutely help your health, but on its own it's unlikely to get you thin. It's hard to burn enough to make a big difference without it chewing your body up in other ways - especially if you're overweight and out of condition to begin with, and so a bit more susceptible to injury than skinny runner types.
Thinking of it as a calories in/out equation is counterproductive for most people, if it boosts your cardio health, gets you more active and maybe converts a bit of body fat to leg muscle, that on its own is a win.
Certainly no harm in having a swig of Gatorade every couple of km if it helps you go further, anyhow.
If fueling during the activity stops you from overeating afterwards and possibly allows you to exercise a bit longer it is worth it, even though it seems counter productive.
It was confusing when the running industry switched from calories to grams of carbs, but that's all anyone talks about now.
"In the aerobic exercise domain up to ~100% of maximal oxygen uptake (VO2max), CHO is the dominant fuel, as CHO-based oxidative metabolism can be activated quickly, provide all of the fuel at high aerobic power outputs (> 85-90% VO2max) and is a more efficient fuel (kcal/L O2 used) when compared to fat."
https://www.gssiweb.org/sports-science-exchange/article/regu...
Try eating 100g of grass per hour during a marathon and you will see. That's the metabolic edge horses have over humans.
1 food calorie as listed on a food label is enough to heat 1kg of water by 1c
https://www.futilitycloset.com/2008/11/16/the-mensa-diet/
(If the nutritional calories in the drink had been only the same number of thermodynamic calories, the drink would have been energetically negative for the body because of its low temperature.)
That common knowledge, nothing revolutionary here.
There are 2 types of sugar, fructose and glucose, you can max out on glucose around 60g/hour and train you guts to max out also on fucose.
Personally I reached 90g/hour without training, no diarrhea or vomiting.
And you know the best ? White sugar in everyone kitchen is almost perfectly 50% glucose, 50% fructose.
You don't need 'advanced' gel to do that, a bottle of water with 120g of white sugar an hour.
And the shoes, yeah they're light but guess what. Other competitors also have sponsors and excellent shoes, some even run bare feet and yet they don't go faster.
No the real reason why he is able to run so fast is first excellent genetic, that's the common base.
Secondly, excellent training, coaching.
Third, his steroid/peds program is on point and his body is responding well to it.
Typically for endurance runner you want profiles with low natural hematocrit so you can max out on the EPO, but there are also other considerations. For instance, are his tendons responding well to GH and other peptides ?
I've never read about that. So it's not "common knowledge" - except maybe in the running community.
I like your comment for putting some facts into place (how far you can go with common options). But as I never heard of this before, I have no idea how common it actually is and the effects and the science around it, what research does say to this, how and why this is used in other sports - or why not.
Did you carry all of these bottles on a marathon? Did you have to stop to get them out of your bag? How did you find drinking whilst running?
I find gels much more compact and for the amount of time I need to run one - over 4 hours there's a lot of weight I need to carry. I can store a lot of them up front in my running vest and keep going.
Do you have any evidence of this?
Like, if we find out the top two finishers here doped very few would be surprised.
That said - it's still an amazing accomplishment.
If you watch Kelvin Kiptum break the world record at the 2023 Chicago Marathon and Eluid Kipchoge break the world record in the 2022 Berlin Marathon, you see the joy and exasperation of their achievement.
That joy was missing in the winners of the London marathon. It's not evidence, but it's an interesting data point. Another data point: Not only did the first two finishers break two hours, the third place finisher, Jacob Kiplimo, broke the world record.
You a cyclist or have you been doing that from running?
From homemade concoctions… you can use maltodextrin for pure glucose.
At what point is this just a performance enhancing “drug” — what makes something a drug?
Now I just throw honey into water on my runs.
It doesn't upset me even though maurten does feel a little better, its worth saving tons of money over buying maurten
But yeah, this is a thing. There is some gut distress for sure at higher levels of intake. See guy finishing second -- still under 2 hrs! immediately puking, which is fairly common at the high intakes. I've heard of Blumenfeld (the triathlete) taking like 200g/hr or more. Insane. Though he's had some epic GI disasters too, lol.
But I only buy for actual races, rest of the time, I do my own 1:0.8 mix with a bit of thickener, in soft flasks. Much more cost effective.
Super shoes are changing the game here allowing for more volume for months without injuries. When you look at Sawe's training his volume is insane. His easy/endurance days are 20km in the morning and 10km in the evening. This is some 100-110 minutes of running on "easy" days. His total time on feet must be around 14-15 hours per week - approaching cycling volume territory (especially when you consider that cyclists do significant % of their volume cruising/descending without putting almost any power at all which inflates the time).
The reason I am asking - I hike a lot, and for shorter hikes (<35km) I don't even bother with food. Just last Saturday I did 28km hike with 550m elevation gain - last meal I had was 5pm on Friday. No breakfast. No problem. I walk at a brisk (for layman) pace, ~7±2 km/h. Am I missing something by not caring about food there, or for my level of "performance" it does not matter anyway? The original question still stands.
These gels and drinks are trying to replenish glycogen stores. The idea is to keep the runner using glycogen for the entire race, as it provides more energy per unit time than fat metabolism.
In your hikes your energy demands probably aren't exceeding the rate that your fat metabolism can provide.
I'd recommend you to do your own research though.
But to add - yes, if you don't eat you will "bonk" on a long bike ride.
Aside from that, this isn't a well-understood topic. Even extremely lean humans have more than enough fat to fuel crossing North American without technically neeeding to eat anything. Fat is less efficient to mobilize than glycogen, and glycogen is less efficient than free glucose already in the bloodstream, so there's some tiny bit of gain there possibly, but frankly, as fast as these guys are going, they're still far enough below lactate threshold that the energy efficiency gain is unlikely to be any real contributor to a faster finishing time. Beyond that, you can't deplete glycogen just from running a marathon, unless you were already depleted at the start of the race. You definitely can and will in longer races, but not a marathon.
Instead, what I'm pretty sure is happening here is you're just hacking the way fatigue works. Your body has more than enough fuel to do insane amounts of work without eating, but bodily systems for doing work are regulated by predictive models. There is no literal fuel gauge in your brain or muscles. They're guessing how much you have left and those guesses are conservative because selective pressures of all animals in the past pretty strongly leaned into leaving something in reserve just in case. If you suddenly find yourself in a struggle to the death, you need to be able to give it your absolute all, and that will require mostly if not entirely glycogen, which means your body's natural regulatory systems will work very hard to keep you from depleting it, so even if you have plenty left, if it's going quickly, you'll get more tired and sore than it was being depleted less quickly. Your autonomic systems don't know you're going to stop at 26.2 miles and eat a giant feast 20 minutes later and the chance of a tiger randomly popping up on the course is effectively 0. All it sees is you're depleting energy stores far more quickly than you can replenish them over the long term and it tries very hard to keep you from doing that.
In a sense, this is all endurance sport really is, training away and hacking away your body's inhibitory mechanisms to get as close as you possibly can to expressing your true physiological limits, but nobody will ever truly get there.
adidas introduces the Adizero Adios Pro Evo 3 – the lightest and fastest Adizero shoe ever, weighing an average 97* grams.
The race-day shoe represents the culmination of three years of cutting-edge research. It is 30% lighter, delivers 11% greater forefoot energy return, and improves running economy by 1.6% compared to its predecessor - making it a record breaker before it’s even laced up.
The shoe will launch with a highly limited release, with ambitious runners able to sign up for the chance to get their hands on a pair from April 23. This will be followed by a wider release in the fall marathon season. The Adizero adios Pro Evo 3 will cost $500/€500.
The Nike Alphafly 3 is the lightest in the series, weighing approximately 7.0–7.7 oz (198–218g) for a men's size 9, and 6.1 oz (174g) for women's sizes.
The PUMA Deviate NITRO™ Elite 3 is exceptionally lightweight, typically weighing 194g (6.8 oz) for a men's size 8 (UK)From the picture it looks like he is only wearing a watch and there is perhaps a little bulge on his left side.
In trail running especially it's not uncommon to exceed the recommendation of 1g/Kg bodyweight/hour, up to 120g of carbs per hour, for those that can take it.
Its great they don't sit idly around in the body and get transformed into fat but rather they are burned in muscles, but still flooding body again and again with this may have long term negative effects that far outweigh any health gains gained from doing these sports, even at such intensity.
Definitely not a diet one could recommend for regular sporty guys, unless they are uber-competitive freaks who have to win at all costs.
Do you have any evidence for this? The problem with simple carbs (if you don’t already have insulin issues) is that they’re easy to digest and provide minimal satiety so you end up consuming significant calories.
But as far as I’m aware there is no evidence that they’re worse for you than the rapid calorie addition.
That said, pretty much everything about highest-end athletics is net negative for long-term health. It’s incredibly hard on the body to run a marathon in general, let alone at record breaking pace.
There were recent tests (in France I think) in schools where 50% or something could not run 1 km (sorry I don't have the details on mobile). These are children who have infinity energy (source: parent).
A typical adult won't make it to 1km (source: going back to sport and dying on a 2.5 km run)
It's easier to draw attention (and therefore sponsorships) if you leave some room to improve on successive attempts. It's riskier to give everything up front and then risk plateauing or regressing in your subsequent attempts.
In his marathon debut too.
I wouldn't have predicted this out of nowhere, but if you told me a marathon debut went this well and asked me to guess whose it was, I like to think I'd have come up with Kejelcha in my top few picks.
That said, great 5000/10000 athletes don't always have great marathon careers. An example from this race is the world record holder at both those distances, Joshua Cheptegei. He's run several marathons but none spectacular by his standards. He was in this race too but 7 minutes back.
Super shoes. Most shoes have carbon plates in them now, they act as a spring, storing energy and propelling athletes forwards.
Better understanding of fuelling. Most athletes are taking between 100-120g carbs (sugar) per hour. Bicarbonate of soda has also been effective.
Better planning tools. Athletes look at elevation, headwind, tailwind and will plan a strategy around going harder into the hard stuff and knowing when they can back off and rest.
And to be honest, probably a metric tonne of PEDs (performance enhancing drugs) - unfortunately this is very common across all sports at the top level.
Note that Sawe funded extra testing drug testing for himself for the 2 months before winning the Berlin marathon. The testing followed Athletics Integrity Unit protocols (so surprise testing etc):
https://www.letsrun.com/news/2026/04/how-sabastian-sawe-conv...
Pretty hard to use the in-competition avoidance strategy like that in this out of competition case though.
This seems unlikely to be true, although it is repeated in every article I read about carbon plated shoes. The people that study them in a lab environment seem to disagree. See some of the papers here:
https://www.wouterhoogkamer.com/science2
However, I agree wholeheartedly with the overall points in your post!
I’m guessing like most things of this nature, you’re likely to have super-responders, responders and non-responders?
Also interestingly, the shoe in this record uses much less carbon than past shoes, both saving weight and allowing even more super foam where much of the energy return comes from. Though there so much variance in shoe design and materials there are only theories on how much comes from the plate vs foam vs stack height vs weight vs other factors.
I wonder where that leaves the barefoot movement. Hype dust?
If I'm going bouldering I absolutely cram my toes into a tiny rock climbing shoe, because it allows me to stand on ledges I couldn't without the extra support from the shoe.
That being said, if barefoot generally feels good to you and you're not chasing the pinacle of performance it's probably a perfectly fine choice for your recreational runs.
The carbon plate revolution is the main driver for drop in times over the last 5+ years
When I was young everyone acted like running was all about who could endure misery the longest. I think if I had known about these aspects it would’ve seemed more strategic and interesting (especially with smart phones to help). Alas, these days all my effort is in making sure my run doesn’t kill my knees :\
Why is going harder in the hard stuff and easier in the easy stuff more efficient or faster than vice versa? I imagine arguments either way:
Going harder when it's easy gives you higher ROI. Or maybe going easier when it's hard is just too slow. And maybe that is too simplistic: Maybe it depends on how hard; that is, maybe there is a threshold.
Wind drag goes up with v squared, so power required goes up with v cubed.
If you run at 105% speed downhill,that requires almost 16% more power to overcome wind drag. You might be better off running at 100% speed downhill (and "saving" that 16% power), and pushing harder to run as close as you can to 100% speed on the uphill stretches that would otherwise have you running slower than 100%. The power used to increase your potential energy going uphill is "zero sum" because you get it back when you go back downhill -n there no pesky v squared or v cubed non linearity there (assuming the race starts and finishes at the same elevation).
40mm stack height maximum One carbon plate only (some shoes were including a second). Must be on sale to the public for < 4 mths before the race in question
Puma makes a shoe that's non-compliant with the above (two plates, not sure about the stack height), for what it's worth.
Based on the quote below, next thing we will see is a "constructors championship" similar to F1 for winning shoe constructor in the 'major' marathons :-(.
" This dominance continued in 2024, with adidas athletes wearing Adizero models winning six out of 12 World Major Marathons – more than any other brand."
and yes, of course i race in super shoes :-).
There are age group leaders as well. That's perhaps a hundred people, of the tens of thousands running next to me.
Marathons are about running my own pace. The fact that there exists a world record is a piece of trivia.
I do find the record fascinating. If I take the 5k, 10k and half-marathon world records and double them then I can run faster than that. But for the marathon I'm a long way off. There's something uniquely difficult about it because it's not just going for a run, but fuelling and training your gut and pacing. I've only done 2 marathons, but I do find them uniquely difficult so for me its extra special to see how fast a human can do it in.
Of course innovation in shoes will have a bigger marginal impact (because physics).
It's also somewhat ironic for a race supposedly modeling a messenger running the distance in an emergency situation.
Three athletes broke the men's world record. One athlete broke the women's world record, and three were in the all time top 5. An Irish record was also broken, likely other countries too that I'm not familiar with.
Not to take anything away from the achievements. Incredible running.
Not so. She broke a record for a female-only-pacer marathon time. The women's world record was much, much faster.
However, because marathon are often mixed gender and the best male runners are significantly faster than the best female runners, it is possible for a woman to be paced from the gun to the tape by a male runner. For this reason, there are separate records for the women's marathon for women's only events.
[0] This is one of the things that made Kipchoge's original sub 2 result not record-eligible.
She broke the thing that the IAAF have gone back and forth on calling "the world record". It's the relevant record for this event - there was no more chance of her beating the man-paced record than of beating the men's record or the Le Mans lap record.
https://news.adidas.com/sabastian-sawe---london-marathon/a/0...
Very few mere mortals could run that fast for even 100m.
That works out to roughly a 16.7-second 100m. While certainly not crawling, that would be a fairly average pace for a fairly fit middle- to early-high-schooler with a bit of practice.
Yes that’s insane to maintain for a marathon, but it’s not even remotely out of reach for 100m for most relatively-fit people at some point in their lives.
https://www.athletic.net/team/770/track-and-field-outdoor/20...
* of course one mile is hardly comparable to the marathon that pros are able to sustain such speeds over...
Afterwards I did some quick numbers and realised the average marathon runner was not only going a lot quicker than I was, but they were doing it for a further 41km
Also bear in mind running a single mile under 4 mins was considered impossible for a long time.
It’s totally remarkable.
It’s not meant to be malicious they just don’t report on things that don’t get enough engagement. If you look at the long list of sports they cover, there’s nothing running related even mentioned. They do now have an article on it in their Olympics category as of 2 hours ago. But I feel like them not having a breaking news coverage on a Sunday in this sport is to be expected more so than your expectation of them covering it.
Was there perfect conditions.or something?
Insane you could run 1:59:41 and not win!
Sabastian Sawe 1:59:30
Yomif Kejelcha 1:59:41
Jacob Kiplimo 2:00:28
The previous official record was Kelvin Kiptum's time of 2:00:35 in 2023. Eliud Kipchoge did 1:59:40 in 2019, but that wasn't record-eligible as it was held under controlled conditions. Source: The article.
It does sound like the course and the weather made it more likely to happen. And technical advances in shoe composition.
> The leading men went through halfway in 60 minutes and 29 seconds: fast but not exceptionally so. But it turned out that Sawe was merely warming up.
Between 30 and 35 kilometres, Sawe and Kejelcha ran a stunning 13:54 for 5km to see off Kiplimo. Yet, staggeringly, more was to come as the pair covered kilometres 35 to 40 in 13:42. To put this into context, that time is two seconds faster than the 5km parkrun world record, set by the Irish international Nick Griggs.
It was only after a 24th mile, run in 4:12, that Kejelcha wilted. But still Sawe kept going. Astonishingly, he crossed the line having run the second half in just over 59 minutes.
“Before 41 kilometres, I’m enjoying, I’m relaxed,” said Kejelcha, who had won silver over 10,000m at last year’s world championships.
“My body is all great. At exactly 41 kilometres, my body stopped. I tried to push, but my legs were done.
Sawe, though, powered on to set the fastest official marathon time in history. For good measure, it was also 10 seconds faster than Eliud Kipchoge’s unofficial 26.2 mile best, set in Vienna in 2019.
https://www.theguardian.com/sport/2026/apr/26/sabastian-sawe...
5km - 14:14 10km - 28:35 15km - 43:10 20km - 57:21 Half - 60:29 25km - 71:41 30km - 1:26:03 35km - 1:39:57 40km - 1:53:39 Finish - 1:59:30
Yomif Kejelcha also ran sub-two, clocking 1:59:41 on his debut marathon
You have to feel for Kejelcha - breaking 2h marathon and not even winning the race!
Like the number one endurance runner in the world will get a minute off their marathon time because a shoe manufacturer spent $1M making custom shoes for that athlete which don't even have a size they're just "For this one specific person, now" but then some guy on Reddit wants better shoes because he's sure his four hour marathon would have been "more like three" if he had those elite shoes instead of the $100 Nikes he wore...
The big improvement then was a carbon plate. Adidas (and others) followed suit. The subsequent improvements since then have been marginal but the margins are thin at that level. In this case the big advancement has been the weight of the shoe.
EDIT: Also it's worth noting these shoes are $500 retail. Adidas will for sure get a boost in sales from this, but there's definitely competition in the $200~$300 marathon running shoe space that won't solely draw everyone to Adidas)
I think the big story here may be the nutrition science to get these guys to absorb a lot of carbs during the run, more than the shoes.
Essentially the argument given was too much advantage came from the shoes and they didn't want racing to be about shoe technology development.
The advancements in shoes have made a measurable impact, but there are lots of optimizations being worked on.
If you're bloody quick and born in Birmingham (either of them) in 1900 you can probably find out about and get yourself a chance to attempt that world record, but if you're born in Kapsabet (in Kenya) in 1900 good luck, even in Nairobi I wouldn't bet on it.
But yeah at this point, “it’s the shoes, stupid” should defo be the main part of the conversation.
It would be interesting to adjust this speed to account for the insane advancements in shoe technology over the last decade. Could it be as simple as measuring the delta in median marathon performance? Then look backwards to, say, 1996 and see what the technology-adjusted 2:00 mark is.
Sub-2hr marathon, beat the previous world record before Sunday, on your first try, and you don't win! Bad timing...
Prize money for London Marathon 2026 - https://www.thesun.co.uk/sport/38880592/london-marathon-2026...
Looks like first place male gets US$330K. Second place will get US$180K.
Divide by 2 to get the approximate hourly rate. :)
There's been lots of research into shoes though, so you might be able to work something out. For instance Jack Daniels (the running coach, not the beverage!) found that adding 100 grams to a running shoe increased aerobic effort by around 1%.
The popularity of running waxes and wanes - and the performance of the median runner varies with popularity.
Back in the 1980s the average half marathon finishing time was 1 hour 40 minutes - whereas today it's a little above 2 hours because there are a lot more people particpating.
London is a fast course. Let’s see what happens in Chicago and Berlin. If it was primarily tech that did it, we should see the record fall again.
This is a nice video of the last 10 mins of the historic marathon race finish
Endurance sports are quite accessible and don't require that much time, effort, or talent to get way better than the vast majority of people, it's just consistency.
Now hitting a 1:30 HM is something different and will be forever out of reach for many people.
- https://www.mdpi.com/2813-0413/5/1/2
Amazing these guys did it in a real race with no one in front of them (at the end at least)
What effects does marathon running have on the body long term?
Also it must be an crazy feeling to be Kejelcha, the guy who came in 2nd place. It would have been a world record, except for Sawe!
It's also worth remembering that "race" is a social construct and is only somewhat correlated to genetics, whereas almost certainly any effect we're talking about here is dominated by genetics, although fun fact, Sawe's uncle is apparently a moderately famous runner and hooked him up with a trainer, so it's not like "Knowing a guy who knows a guy" didn't help and that's way less to do with genetics.
The "scientific racism" of confusing "The world's fastest sprinters tend to be from this Haplogroup" with "Everybody in that Haplogroup is an Athlete and so can't do intellectual stuff" is completely insane, that's how you get "I bet this old white man from a Reality TV show will be a better executive leader than that black politician we had last time".
I used to love F1 for the tech that would filter down to my car in ten years time, but that is not a thing anymore.
I for one love the advances in technology in something as supposedly simple as a shoe. And maybe I'll get to use it on a hike in a few years.
These shoes are practically disposable. They trade longevity for noticeable gains in performance. Even the tier below don’t last very long. This is not tech that is going to filter down to your hiking boots.
That's not me being sarcastic. I never, ever thought this would happen
Edit: I was thinking in km/h and mixed it up. Sorry.