There’s a point, usually somewhere between mile 19 and mile 22, when I notice my shoulders have crept up around my ears. I have no idea how long they’ve been there. I drop them, open the hands that have closed into fists without my noticing, and for a few hundred yards I’m back to looking like the runner who stood at the start line. Then my pelvis starts sliding back and my torso tips forward a few degrees. My stride shortens and lands heavier, as if with every mile someone had slipped another stone into my pocket. From the outside it’s obvious. In the photos from the final stretch I look like a man running while sitting on a chair that isn’t there.
Anyone who has run long recognizes the shape of that chair in other people before they see it in themselves: the head lolling, the chin lifting to hunt for air, the arms that stop driving and only keep balance, the hip collapsing on the side of the planted foot. It’s the moment when running loses its architecture and turns into transport, a body hauled to the finish the way you haul a suitcase.
For years I treated that shape as a private matter. It was built from long runs skipped in February and a first six miles run at a pace that wasn’t mine. It was the bill for the day, and I paid it.
Last spring, in London, someone tried to send that bill to a piece of clothing.
Eleven Seconds in London
Two men under two hours in the same marathon. Until that day the number had existed only in Vienna, in October 2019, inside a race tailored to Eliud Kipchoge, with pacers rotating in and out and a line of light projected onto the asphalt to mark the pace, and for exactly that reason never ratified as a record. In London it happened in a regular race, with real opponents and no stagecraft. Sabastian Sawe won in 1:59:30, a new world record. Yomif Kejelcha finished in 1:59:41.
In the photos from that morning Kejelcha looks dressed like plenty of elite marathoners, a singlet and tight shorts down to mid-thigh. You have to look closer to see that singlet and shorts are a single piece, a black bodysuit running from shoulders to knees without a break. It’s the Techfit Endurance Suit, and adidas had prepared one for Sawe too. At the last moment he passed on it and started in tight shorts and an ordinary singlet, worn untucked.
The suit became news only in May, when The New York Times wrote about it and the brand put a number on the table: more than a 1% gain in running economy. That figure is adidas’s own claim, and so far no one has verified it independently.
Those eleven seconds stay out of this conversation. Two bodies with different histories and a single race: a comparison like that tells you nothing about the suit, in either direction.
Another detail has stuck with me. A man on the verge of a world record found himself looking at a garment designed to help him and chose an ordinary singlet instead. I don’t know his reasons, and I won’t try to guess them.
Clothing That Works on the Body
To understand what this suit does, according to the people who designed it, you have to go back to the invisible chair. The bodysuit is crossed by bands of thermoplastic polyurethane, placed to stabilize the pelvis and hips. The brand explains that the muscles holding the pelvis and trunk steady work together with the ones that stabilize the hip, and that reaching both takes something running across the whole body: hence one piece rather than two separate garments. The claimed advantage would come mostly from there, from holding off the collapse of posture as fatigue climbs, more than from cutting air resistance.
For as long as I’ve been running, clothes have had a defensive job. They shield me from January wind and keep a seam from sawing into my armpit at mile 12. At best they slip through the air a little better than a cotton T-shirt. Even the track bodysuit, which sprinters and middle-distance runners have worn for years, works on the surface: it smooths the runner’s profile and leaves the body underneath as it is. The London suit, if you take its designers at their word, reaches into the body underneath.
That’s where clothing stops covering and starts supporting, and it enters the ledger of fatigue right alongside the muscles.
How much that support is worth, for now, lives only in the brand’s own data. LetsRun put the simplest question to adidas: what that 1% was measured against, a singlet and shorts or the bodysuits already seen on the track. It’s the right question, and it has the merit of taking the idea seriously. Because the idea, number aside, is new: for the first time a marathon garment is being presented as a remedy for the shape fatigue presses onto the body. In the mountains the same intuition has already taken the form of hiking exoskeletons, openly designed to lighten the climb — though in a very different setting. In elite marathoning it arrives more quietly, stitched into a black fabric that in photos passes for a singlet.
Swimming Has Been Here Before
The New York Times piece sets the adidas suit beside the LZR Racer, the swimsuit Speedo used to upend swimming in the late 2000s. The comparison holds up better than it first appears. That suit, too, did more than glide through the water: it supported the swimmer’s midsection to keep the body flatter in the pool. Posture, once again, handed over to something outside the skin.
Anyone who watched races in those years remembers swimmers wrapped to the ankles, glossy as seals on the starting blocks. After the LZR came suits made entirely of polyurethane, and the results sheets began filling with times nobody could credit anymore, whether to the stroke or to the suit. In the summer of 2009 the World Championships were swum in Rome, at the Foro Italico, and it was during those championships that the international federation decided to close the chapter. From January 1, 2010, full polyurethane suits were banned: textile only, waist to knee for men, shoulders to knee for women.
There’s something almost anatomical about that solution. To restore order, the federation drew lines on the body marking how far fabric could reach, and the waist and the knee became sporting borders. Michael Phelps, who had won in Beijing wearing the LZR, said in Rome during those days that people could finally go back to talking about swimming instead of swimsuits.
The rule came two seasons later. The times, by then, had already been swum.
The Rule That Comes After
In running we watched the same sequence play out a few years ago, with shoes. Kipchoge ran Vienna in a prototype, and only at the end of January 2020 did World Athletics set a limit of 40 mm on sole thickness and allow no more than one rigid plate. Since then the argument over where the advantage lives has shifted more than once, and today some look for it more in the foam than in the plate.
I have a hard time reading bad faith into that delay. Whoever governs a sport writes rules about what already exists and measures with the tools at hand. Thickness can be checked with calipers, a plate can be counted. Posture held together over twenty-five miles slips past every caliper.
To know how much of an upright torso belongs to the fabric, you’d have to take the runner apart.
Then again, Formula 1 has taught us that designers are doing their job when they push where the rulebook hasn’t reached yet. Without that push the federations wouldn’t even know which questions to ask, and much of what we now take for granted on an amateur’s feet was born that way, ahead of the rules and in plain sight. For a garment like the one Kejelcha wore, a rule written for it doesn’t exist yet. When it comes, if it comes, it will be chasing bodies that have already run.
What’s Left of the Athlete
At this point it’s tempting to invoke a pure body, the athlete of old, with nothing on him to help. I’ve never met that athlete. I run on foam that gives back part of the energy, with a watch on my wrist flashing my pace every mile. The line between body and equipment has been moving for as long as sport has existed, and every generation redraws it a few inches further along.
The London suit, though, moves it to a delicate place. Shoes and foams work on the footstrike, on contact with the road. This one, going by what its makers say, works on form, and for anyone running a marathon the form of the final miles is a signature before it’s a flaw. You can read in it how you trained and where you cut corners. If a garment is what holds it together, it becomes hard to say who owns that pelvis still riding high at mile 25.
Something, in any case, stays outside any fabric. The polyurethane bands, if they work the way adidas says, may help the pelvis stay where it belongs. But the pelvis has to get there first, and it gets there carried by months of training and by a mind that decided at mile 19 to keep going. That part needs no regulation, because so far no fabric can do it for you.
Of the London record, for now, I’m keeping Sawe’s singlet, billowing over his chest and falling back with every stride.
The fastest marathon ever run still has creases in it.