Running a marathon to the limit of my possibilities without a modern running shoe (with a carbon plate and ultra-responsive foam) is an idea that has been circling in my head for some time. To know how far my body would go with the technological conditions of 10 or 15 years ago. Trying to quantify the chronometric advantage that the shoes with which the vast majority of athletes, or at least those aiming for certain time records, compete today provide.
If you think I’m going to talk here about that marathon you’re mistaken. For the moment I’ve only tested a 10K.
On September 20 this past year I competed in the Barcelona Mercè Run and did so wearing the Hoka Mach 7, a model without a carbon plate and without the latest generation foam, but it has everything you need to push yourself to the limit on asphalt. Lightness, response and immense comfort. In fact, it’s the shoe I wear most in tempo or threshold workouts, those where you’re looking to push yourself but not blow up.
My last time without carbon was eight years ago
The last time I competed without a carbon plate was the 2018 Behobia San Sebastián. I did it wearing Adidas Adizero Boston on my feet and I remember talking with my teammate Javi Moro after finishing the race that maybe it was the last time we’d compete without “the new thing.” That race was sponsored by Adidas but both of us already had the first Nike Vaporfly 4%, which I used for the first time in a competition at a 10K in Aranjuez, where I first managed to dip below 32 minutes. Coincidence? I don’t think so.
Since then, dozens of 10K races, half marathons and full marathons, all with state-of-the-art sneakers on my feet. Until the Mercè Run 2026.
What does it feel like?
The big difference, in my view, is on the descents. The first kilometers you barely notice it, but fatigue starts to show up later. You feel fast, but the clock reflects a time that isn’t the one you normally associate with how you feel.
I clocked 32:30 and I think I could have been around 32:00 or lower. It’s true that the race start time, very early in the morning, and waking up 50 minutes before the start without breakfast didn’t help either.
But there’s something that caught my attention: the shoe doesn’t let you hide mistakes as much when you’re fatigued. In a descent, for example, with a carbon-plate shoe and very reactive foam I feel I can lean a bit more, keep the pace, and have the shoe do part of the work.
The difference is that you don’t have that sense of something under your foot helping you keep going when your legs start to rack up the kilometers.
With the Mach 7 I had to be more mindful of how I landed and of maintaining speed on my own. It doesn’t mean they’re slow shoes, far from it. In fact, I think they’re a fantastic option for running fast. The difference is that you don’t have that sense of something under your foot helping you keep moving as your legs accumulate kilometers.
And that, in a 10K, can be managed. In a marathon, where there are still 15 or 18 kilometers left when fatigue appears, it could be a different story.
Would I do it again? Will I end up running a marathon?
Yes, I would do it again, though the decision for a marathon will be tough. In a 10K or a half, I feel that it matters less, but in a marathon you’ve had to train a lot. It implies a very conscientious training regimen that would sacrifice the time goal.
If after months of preparing a marathon I reach the starting line in conditions to run at the limit of my possibilities, do I really want to give up a technological aid that I’ve been using for the last eight years? Probably not.
I’m trying to understand better which part of performance comes from the legs and which from the gear you wear on your feet.
But I also think it’s worth trying. Not so much to prove that you can run fast without a carbon plate, but to understand better which part of performance comes from the legs and which from the gear you wear on your feet.
For now, the experiment sits at a 10K and 32:30. The true test, if it ever arrives, will be the marathon. And there it will be interesting to compare the sensations, the pace, and above all how the body responds when the kilometers begin to reveal where a modern shoe makes a difference.
