The wall didn't die. We just learned how to fuel past it.

Sebastian Sawe ran 1:59:30 in London this April, the first time anyone has gone under two hours in a record-eligible marathon. Over those two hours he took on around 230 grams of carbohydrate: roughly 25 grams at the start, then 25 more every five kilometres, with a bigger hit near halfway. He did not fade at the end. His last seven kilometres were quicker than the rest.

A run like that brings back an old claim, that the wall is finished, that foam and sugar have quietly retired it. I don't buy it, and the reason matters more than the headline. The wall hasn't been abolished. It has been made avoidable, by a handful of things we now know how to train, and at the top of the sport they train them better than anyone ever has. For a runner who hasn't done that work, the wall is exactly as real as it was twenty years ago. The better news is that the work is learnable, and most of it is the cheapest kind of gain there is.

What actually causes the wall?

It helps to be precise here, because the folklore version is vague. Your muscles run most efficiently on carbohydrate, stored as glycogen, and your stores are finite. Geoff Burns, a physiologist with the US Olympic and Paralympic Committee, calls it a thermodynamic problem: you start a marathon with somewhere around 2,000 to 2,500 calories of stored carbohydrate, and you burn roughly 100 calories a mile. The sum tells you where it runs out. When you get critically low, your body leans harder on fat, which is slower to turn into usable energy, and the pace bleeds away. That is the wall, and it is real physiology, not a failure of grit.

Why don't the best runners hit it anymore?

If the physiology hasn't moved, the inputs around it have. Three of them matter.

The first, and the biggest, is in-race fuelling. Sawe's 230 grams would have been unthinkable a decade ago, when we assumed that much sugar at speed would only make you sick. Hydrogels and glucose-fructose blends, which use separate intestinal transporters so the gut can take on more at once, changed what the stomach will tolerate. And the gain is measurable: runners taking 120 grams of carbohydrate an hour have been recorded using about 2.6 percent less oxygen at the same pace than runners on 60 grams. Same speed, lower cost.

The shoes are the second, worth somewhere around 2 to 3 percent in metabolic demand. Real, and worth having, but smaller than the volume of argument around them suggests.

The third one compounds. Better fuelling and recovery let the best runners train harder. John Korir went over 150 miles a week several times building for Boston this year, where his brother Wesley topped out closer to 130 a decade earlier. The bodies aren't different. The recovery between hard sessions is, and a lot of that is fuelling.

What does this mean for your marathon?

This is where the headlines mislead a three- or four-hour marathoner, so I'll be straight about it. The elite ceiling moving does nothing to your physiology. The curves that actually build a sub-three marathon, your aerobic base, your threshold, your economy, are exactly where they were before anyone broke two hours. The shoes will give you a couple of percent. They will not hand you fitness you haven't built, and they will not fuel a race you haven't practised fuelling.

We put it this way at the Clinic: sleep and consistency beat any shoe, and the shiny stuff, the carbon plates, the wearables, the lab tests, is the small percentage you chase once the base work is genuinely in. Fuelling is the exception. It isn't a marginal gain, it's close to a fundamental, and it's the lever most runners have never seriously pulled. You can't buy a bigger engine. You can train your gut.

How do you train past it?

So here's how I'd have you do it.

Fuel every long run like it's the race. This single habit is what separates the runners who fade from the runners who hold on. Whatever you plan to take on race day, rehearse it, and build it across the block. Start around 60 grams of carbohydrate an hour and work up as your gut adapts. The gut trains in exactly the way your legs do, a bit more each week, practised until it's boring.

Carb-load properly into the race, which means around 8 to 12 grams of carbohydrate per kilogram of body weight across the two days beforehand, not one big pasta dinner the night before. It's one of the few things that reliably changes how the closing miles feel.

Leave the fasted and low-carb runs alone. I'd steer clear. For the marathon you want a gut used to taking on carbohydrate and a body used to running well-fuelled, and training depleted teaches it the opposite of that.

And pace with restraint early, because pacing is a fuelling decision before it's anything else. Going out too hard doesn't only tire your legs, it burns through glycogen faster and drags the wall forward into the race. An even effort protects the fuel you'll want at 35 kilometres.

The last part is the one runners fight hardest. You don't need to rehearse the full distance to be ready for it. The closing 10 kilometres come from your accumulated volume, from running tired in training, from arriving fresh, from fuelling, and from knowing the work is done. Running 42 kilometres in training mostly digs a hole you then spend a fortnight climbing out of.

Sawe didn't beat the wall by finding a way around the physiology. He beat it by training the things that keep glycogen available longer than his rivals could, then pacing so he never ran out. That same path is open to you at your own level, for the price of the fuelling work most runners skip. Your next long run is where it starts.