Should I Always Train in Carbon Shoes?

Since the emergence of carbon shoes in 2016, the running world has changed dramatically. Where personal records used to stand for years, they were suddenly being broken at a rapid pace. The sport has changed, but does that apply to everyone? Are carbon shoes only for top athletes, or can recreational runners also benefit? And more importantly, what are the pros and cons?

The revolution started at Nike

The big turnaround began in 2016 when Nike launched the Vaporfly 4%. This shoe was equipped with a carbon plate in the midsole and a new, ultra-light foam (ZoomX), which together provided a striking "spring effect." Nike claimed that runners wearing these shoes would run 4% more efficiently on average. This was not just marketing talk: scientific studies confirmed the gains, and top athletes set records en masse.

In 2019, Eliud Kipchoge drew global attention to the shoes by running the marathon in under 2 hours (in a specially organized, unofficial race). He wore a prototype of what would later become the Nike Alphafly. Although not recognized as a world record, it was a clear signal: these shoes make a difference.

What do carbon shoes actually do?

The technology behind carbon shoes revolves around three elements:

• A stiff carbon plate, which accelerates the roll of the foot and stimulates forward movement.
• Responsive, springy foam that returns energy with every step.
• A rocker-shaped sole that makes the stride smoother and contributes to a natural "rolling" push-off.

Together, this results in less energy loss and a higher running speed with less effort.

Performance improvement: Who does it work for?

It's clear that carbon shoes work. But who exactly? Most studies show that faster runners and elite athletes benefit the most. Research shows:

• Elite athletes improve their running times by an average of 2 to 4%, depending on the model and distance.
• Fast recreational runners (e.g., marathon runners <3:30 or 10 km runners <50 min) achieve an average gain of around 1.6%.
• Slower runners (<6:00/km) have a much more variable effect: 31% of them do not benefit from carbon shoes, and some even run slower with them.

A one-sided picture?

Important to note: most of the studies in which the above figures were measured used the Nike Vaporfly. This shoe is designed for fast runners. For slower or differently moving runners, the effect may therefore be different, especially with other models or brands. A recent study (Van Hooren et al., 2025) added some nuance to this. In this study, several shoes with AFT technology (such as the Asics Metaspeed Sky+ and Kiprun KD900X) were tested on recreational runners running at 10 km/h. The results? An average improvement of 2 to 4% in running economy, comparable to elite athletes.

The caveat: the effect varied greatly from person to person. Not everyone became faster. Some runners saw little or no improvement, or even performed worse in certain shoes.

More importantly, no clear link was found between body type, muscle structure, comfort, or running style and the effect of a specific shoe. The conclusion: the choice of carbon shoe must be tailored to the individual. There is no universal model that works for everyone.

Are there any disadvantages to carbon shoes?

Although carbon shoes offer impressive advantages, they are not without their drawbacks:

1. Price

A pair of carbon shoes costs between 200 and 300 euros on average. That is considerably more than a regular running shoe.

2. Limited lifespan

Most models lose their resilience after 200 to 300 kilometers. This makes them particularly suitable for competitions or a few important training sessions and not as everyday running shoes.

3. Risk of injury

The biomechanical change of a carbon shoe compared to a normal running shoe increases the risk of injury in several ways.

The carbon plate increases the flexural stiffness of the shoe. This partially shifts the energy storage and recovery from the tendons and muscles to the material of the shoe. In the short term, this saves energy by relieving the muscles and tendons, but in the long term it entails risks. These risks arise as follows: studies show that with stiffer shoes, the calf muscle fibers shorten less and work more slowly during the stance phase, causing this muscle group to be underloaded.

This puts a different kind of strain on the Achilles tendon, which is attached to the calf muscle. In addition, there is less need for the small foot muscles to exert themselves, because the stiff shoe takes over the foot stiffness. Muscle activity around the ankle also decreases; the stiffness around the ankle shifts from the ankle to the shoe. In contrast to the foot and ankle muscles and the calves, the hip extensors, hamstrings, knees, and shins have to work harder to absorb the impact of the reactive shoe.

In summary: carbon shoes take on part of the running movement, relieving the foot, ankle, and calf muscles. At the same time, the Achilles tendon is subjected to different stresses and the shins, knees, and hip muscles have to work harder to absorb the impact. This changed load pattern therefore causes underloading on the one hand and overloading on the other, creating an imbalance and increasing the risk of injury.

How often should you train in carbon shoes?

It is important to allow the body to gradually get used to the mechanical changes caused by carbon shoes. Start with one short training session per week in carbon shoes and gradually increase this to a maximum of two sessions per week. Speed runs, interval training, and race simulations are best suited for the use of carbon shoes. For warm-ups and cool-downs, it is best to use your trusted training shoes and avoid carbon shoes during easy or recovery runs.

Rotation in training shoes is essential to vary the load and prevent overloading and underloading. By using different shoes, muscles, tendons, and joints are loaded in a more balanced way.

In addition, integrate targeted strength training for the foot and ankle, with specific attention to ankle stiffness exercises. Continue to strengthen and stress the calf muscles and Achilles tendons structurally, so that the body is better able to withstand the higher forces and different roll-off that carbon shoes entail.

Conclusion

Carbon shoes have changed the world of running. They offer noticeable benefits for top athletes and fast recreational runners, and even slower runners can benefit from a well-fitting model. Recent research shows that performance improvement is not only reserved for elites, but that the effect is highly dependent on the individual runner and the choice of shoe.

Please note: the combination of a stiff plate and springy foam can change the load on the body. When tired or after prolonged use, this can lead to overloading of muscles, tendons, or joints. Alternating with traditional shoes and a gentle build-up are essential.

Want to get faster? Then a good training plan, sufficient recovery, and being able to train injury-free for a long time are the most important conditions. Carbon shoes can help with this, provided they fit you well and you use them at the right time.