The past five years has witnessed a boom in carbon-plated running shoes. Following Nike’s revolutionary Vaporfly 4%, most of the major running shoe brands began developing and releasing their own carbon-plated models - shoes with a rigid carbon-fibre plate embedded in the midsole.
These shoes are all about improving your efficiency as a runner and as a result, enhancing your performance, but there’s more to them than speed. Carbon-plated running shoes offer several genuine benefits and have the potential to help all sorts of runners achieve their goals. They're not just for fast and elite runners.
So before you dismiss them as “Not for me,” read on…
The tech behind carbon plate running shoes
We want to spend the least amount of energy possible while running at our target pace to maintain it for the targeted distance. It’s mainly through our training that we’re trying to become more efficient runners, however, running shoes can help us too.
Carbon plates have a range of benefits when used in running shoes. The effect on performance is dependent on the shape of the plate, its position, and what material it’s coupled with.
How do carbon-plated running shoes work?
Before we go on, it’s important to make one key statement: a carbon plate does not act as a spring. This is a common misconception and it's damaging. It suggests that carbon plate shoes are aiding runners in a way that isn’t in the spirit of the sport. Instead, carbon plates work in harmony with the rest of the midsole to help optimise running economy. They either improve performance or reduce the stress placed on the muscles.
How carbon-plated shoes work is a combination of factors, mainly reducing ankle flexion and increasing energy return from the midsole.
Carbon plates reduce ankle flexion by improving forward momentum
The main effect of a carbon-plated shoe is to reduce ankle flexion and therefore improve ankle mechanics. While running, we're constantly battling forces that are trying to slow us down. One of our greatest challenges is to simply move forward. This is where the carbon plate can help.
We must use the word "lever" loosely, but that’s a good way to think about how the carbon plate works. The amount of "work" that the ankle joint has to do at a given workload is reduced by the carbon plate as it helps the natural rolling process. This is the reason pretty much every carbon-plated shoe has a curved midsole geometry or "rocker."
By curving the midsole and adding a stiff structure, forward momentum is increased, reducing the stress through the ankle. This geometry also helps lift the heel of the shoe faster. This lets the hips pass over the centre of gravity, again improving forward momentum.
Carbon plates enhance energy return by improving the stability of the platform
A carbon plate also adds structure and stability to a midsole foam. Social media throws up the term "superfoam" quite a lot, but only a few models use a true superfoam.
This is normally made from a Polyether block amide or PEBA (trademarked as PEBAX) and it breaks the mould, so to speak. Not only are these foams incredibly soft, they offer the highest levels of energy return; the best of both worlds. However, these foams don’t offer much structure and aren’t necessarily very stable to run on.
A carbon plate creates a degree of rigidity and therefore improves the stability of the platform. The carbon plate also enhances energy return from the midsole material as a result of the additional stiffness.
Additional benefits of carbon plates
There’s also a hypothesis that certain foams, when coupled with a carbon plate, will reduce muscle vibration. Vibration (movement or oscillation) accounts for about 20-per cent of all input load. Carbon-plated shoes could make someone run faster as a result of increasing energy return, but also by reducing the rate of fatigue. The latter is the more exciting notion and one which has the greatest application when it comes to future developments in running footwear.
Sore muscles after hard sessions often hold runners back. The end of races are normally painful affairs as legs start to tighten up and it gets progressively sorer to run at the same speed. More work needs to be done to ascertain exactly what mechanisms are at play, but there is strong anecdotal evidence to support the claim that runners won’t feel as sore or fatigued at the end of runs, or even after runs, due to the way carbon-plated shoes reduce ankle flexion and the amount of work done at a given intensity.
Other variables in consideration to carbon plates performance
The benefits that a runner will get from a carbon-plated shoe, and how it will work for them, will also depend on their running style and biomechanics. Studies that have assessed the effects of carbon-plated shoes on running economy have found significant variances in how they change performance between runners. This might be down to variances in biomechanics like:
- Where someone lands in relation to their centre of gravity
- Stride length
- Stride frequency
- Ground contact time
- Foot landing position
There are a lot of variables at play when it comes to running and everyone is different. This makes it difficult to quantify the benefits as a blanket statement for every runner, e.g. "These will save everyone four-per cent energy at a given speed." Some runners may find that carbon-plated shoes make them faster and harder running becomes more sustainable. Others may find that carbon-plated shoes reduce fatigue levels after sessions and they can recover better.
Due to the variance in benefits runners get from carbon-plated shoes and the potential applications, we’re now seeing a broad range of options that have different features. In reality, brands are only just scratching the surface of what’s possible.
Some models have the carbon-plate positioned right under the foot for maximum stiffness, whereas others embed it in the middle of the foam to deliver a softer feel. Designers shape plates in certain ways to create specific outcomes and in some cases, they only add plates to a specific part of the midsole.
It’s worth noting that the stiffer material doesn’t always have to be made of carbon. Nylon and TPU plates can mimic the stiffness of carbon plates and offer a different sensation with similar outcomes.
What’s the best carbon-plated running shoe?
Extensive testing and research goes into the design of carbon-plated shoes, so they tend to command a higher price tag. The best advice is to pick the one that best suits your needs. Run4It's range of carbon-plated shoes varies in terms of cushioning, and whether they’re suited to training sessions or specifically for racing.
The process of choosing a carbon-plated shoe is the same as any standard road running shoe. The feel and fit of the shoe will be the primary factors to decide which one is the best for you. Nobody can point to one best carbon-plated shoe.
You’ll need to factor in the distance you want to use them for and how they’re going to sit in your shoe rotation. This means we won’t advise the same models if you’re looking for an additional pair to use for races and faster-paced sessions only, as opposed to if you’re looking for an all-rounder for daily use.
If you’re exclusively looking for a racing option to add to your current running shoe rotation, we’d suggest considering:
If you’re looking for a plated shoe to cope with races and training, these models will be more suitable:
- adidas Adizero Boston (Using energy rods which match the alignment of the metatarsal heads, which a runner will be less aware of than a carbon-fibre plate)
- Asics Magic Speed
- Nike Zoom Fly
- Saucony Endorphin Speed (Has a nylon plate instead of a carbon plate)
All the carbon-plated options are neutral so a gait analysis won’t be as necessary as when choosing your daily road running shoe.
However, we strongly advise that you visit your local running shop so that they look at your gait anyway, and advise the best model to suit your running style and goal.
Check out our shoe reviews for further information on specific models in the range.