Carbon-plated running shoes are the new and upcoming trend, but how much of it is just hype, and how much of it relies on real science?
The original trendsetter, the Nike Vaporfly 4%, claimed to improve running economy, which is the amount of oxygen that can be delivered and used by exercising muscles at a specific velocity. Countless independent lab tests and multiple marathon victories proved that the shoe did help the runner. Soon after, HOKA ONE ONE and New Balance released two more carbon-fiber shoes.
Carbon fiber is made of thin, strong crystalline filaments of carbon. It is five times stronger than steel and twice as stiff but also very lightweight, which is why many engineers use it for various parts from auto racing to aerospace.
By adding carbon fiber to shoes, it is said to boast improved cushioning. That allows for quicker recovery times, reduces muscle fatigue, increases speed and lowers chronic injuries to the knees, hips and ankles. The carbon midsoles change the way the runner lands in the shoe and, essentially, allows them to spring up while they perform.
While the first carbon-plated shoe was released by Reebok in the 1990s, the forefoot was too stiff and did not garner the right attention. Nike adapted the design and technology to create something a lot more lightweight and responsive.
The science behind it is quite simple.
The carbon plate acts as a lever to effectively roll the foot forward through the force developed by the leg muscle and propel the body forward through the gait cycle—the act of taking a full stride. It also keeps the big toe joint straighter during the toe-off, saving energy. Bending the joint also would waste the running economy.
In the Nike Vaporfly 4%, the engineers introduced a jauntier curve to the plate to reduce the extra load on the ankle and protect the runner from eccentric loading, which is the braking action of the leg muscles each time their foot hits the ground. This inflicts muscle damage that slows them down and leaves them sore.
The carbon plate, which has the right footwear mass, cushioning and bending stiffness, allows for maximum running economy. It is like the fuel economy in a car since it measures how much fuel is needed to travel a certain distance. The runner with a better running economy can use less energy/oxygen than someone with a low running economy, meaning the person with a higher running economy can run a long distance with ease.
In a study by Springer, the new Nike prototype, which features a ZoomX foam made with polyether block amide and an embedded carbon fiber plate, was tested. The shoe stored more mechanical energy at an 87 percent energy return, twice as much as other shoes. Since the shoe has an elastic midsole and a carbon-fiber plate, the runner does not need much muscular force to perform.
To determine running performance, the study used top-level Kenyan marathon runners to see if there was a reduction in energetic cost. Subjects ran with a 1 percent increase in vertical ground reaction forces, 0.6 to 0.8 percent slower step frequencies, and 0.6 percent longer contact times in the carbon-plated shoes. Due to these three factors, the carbon-plated shoes substantially lowered the energetic cost of running by 4 percent on average. The respiratory exchange ratios and the rate of oxygen consumption stayed similarly the same on average.
According to Springer, the reduced running economy means that there will also be around a 3.5 percent improvement in running velocity.
Running shoes always stuck to traditional and simple ways until the carbon-plated running shoes scientifically proved that it enabled athletes to reach new records, pass limits of human performance and win marathons globally. There’s no question about it. The new technological shift in the running industry is here to stay, and many more shoes are on the way.