Carbon-fibre plates in run shoes: what they are, how they work and whether they’re worth the hype

In the quest for ever lighter, more rigid and responsive kit, carbon fibre has long been at the forefront of evolving sports technology. For triathletes and cyclists, much of its influence has been witnessed with faster bikes, while more recent years have seen the rise of the carbon-plated running shoe. But are they really worth the hype?  

These days, carbon-fibre blades have spread to footwear on a mass scale. In 2019, Nike’s innovative and contentious Vaporfly polarised audiences who saw it either as a free market novelty at its finest, or about as welcome as the tsetse fly. Regardless, its seismic impact on the running industry, and therefore the final leg of the triathlon, was undeniable. 

But why the furore? Do carbon fibre plates really improve running speed? Is it fair? And does fairness matter anyway? Aside from at elite level, does carbon make much difference to performance? 

This article sets out to provide background and answer some of those questions.

What are carbon-fibre plates?

Carbon-fibre plates are thin, rigid inserts embedded within the midsole of certain running shoes. Made from carbon fibre, a lightweight yet exceptionally strong material, these plates are designed to enhance propulsion and energy return during running. Their stiffness helps stabilise the shoe, reduce energy loss, and improve the efficiency of each stride.

The introduction of carbon-fibre plates marked a significant shift in running shoe technology, combining cutting-edge materials with biomechanical insights to create footwear that could boost performance.

The birth of a game-changer: Nike’s Vaporfly

In 2013, Nike began developing its Vaporfly shoe, taking out a series of patents as it combined responsive Pebax foam (a type of thermoplastic polymer branded as ZoomX by Nike) with a stiff carbon-fibre plate embedded in the sole.

For many onlookers, the Vaporfly seemed like the next – albeit strange-looking – evolution in running shoe design. Some dismissed it as part of the marketing hype surrounding Nike’s initial Breaking2 attempt, the 2017 exhibition on the Italian Grand Prix circuit. During this event, Kenyan runner Eliud Kipchoge donned the Nike Zoom Vaporfly Elite and narrowly missed breaking the 2-hour marathon mark, finishing just 25 seconds shy.

This groundbreaking performance, coupled with the distinct look and feel of the Vaporfly, sparked widespread interest in carbon-fibre plate technology and its potential to revolutionise running.

But aren’t there laws in place to govern shoe tech so it is fair to all?

World Athletics has established specific regulations for the use of carbon-fibre plated running shoes in competitions to ensure fairness and athlete safety. These include: limiting the sole depth to 40mm thick, each shoe can only have one plate and located in one plane (stacking or overlapping of plates prohibited), and the shoe must be available to purchase to the general public at least four months prior to competition use. 

How do carbon-fibre plates make you a faster runner?

Carbon-fibre plates in running shoes have become ubiquitous, and their performance benefits are well-documented. Studies indicate that these shoes can improve running economy by approximately 2.7% to 4.2%, enhancing efficiency and speed (Journal of Exercise Science, 2022).

This is worth pausing to contemplate. Anyone who has run a marathon or appreciates what it entails, can acknowledge that 4% less effort isn’t just nibbling at the edges, it’s a colossal chunk. For a 3hr marathoner, it would lop off minutes over the 26.2miles, something that could otherwise take years of training to accomplish. 

The stiff carbon-fibre plate aids in quicker compression and expansion of the midsole foam, returning more energy to the runner (lab tests put this at over 80% and the highest ever recorded).

This ‘rocker effect’ promotes a smoother and more efficient forward motion. The plate also stabilises the ankle, reducing rotational force and lessening calf workload. This combination helps runners maintain performance longer during a race and recover more quickly afterward. The plate also keeps the toes straight, further reducing energy loss.

Potential drawbacks to carbon-fibre running

While carbon-fibre running shoes offer performance benefits, they come with certain drawbacks. Their higher cost makes them less accessible to many runners (the Varpourfly was sold at an eye-watering $250). 

They’re also expensive and thus price many out, which is exacerbated if the durability of the shoe is poor and there have been reports of the foam losing responsiveness after a few hundred miles. The increased stiffness may also contribute to injuries, particularly in runners lacking proper foot and ankle stability. While those not used to such thick, bouncy soles can suffer from higher instability while running, potentially increasing the risk of injury.

Are carbon-fibre running shoes worth the hype?

Carbon-fibre plated shoes have revolutionised running, especially in race conditions, offering improved efficiency and speed. However, their benefits may be more pronounced for fast and elites athletes than recreational runners. The high cost and potential injury risks necessitate careful consideration. If you’re on the fence about whether to invest in a carbon super shoe, it’s advisable to firstly assess your individual biomechanics and training needs. While carbon-plated running shoes can enhance performance, they are not a substitute for proper training and conditioning.

How to choose the right carbon-fibre running shoe for you

When choosing a pair of carbon-fibre running shoes, there are a few factors to consider. Firstly, whether you will you be running on trails or road, the geometry of your feet (are they narrow, wide, or average), and what distances you want them for.

We recommend that you try on multiple pairs to assess comfort and fit, as individual preferences vary. Don’t be afraid to ask the advice of the experts at specialty running stores, can provide personalised recommendations. As a starting point, take a look at our recommendations below.

Here are some of our favourite tried and tested carbon-plated running shoes :

• Hoka Carbon X3 review
• Saucony Kinvara Pro review
• Salomon S/Lab Phantasm 2 review
• Nike Zoom Fly 5 review
• Hoka Cielo X1 review
• Under Armour Velociti Elite 2 review
• Saucony Endorphin Edge review
• Kiprun KD900X review