How Running Shoes Make You Run Faster

In 2016, the running world was revolutionized by one pair of shoes: the Nike Vaporfly 4%. The first time they were used, the world record in the marathon dropped by 78 seconds-- the largest time improvement in over 50 years. In that year’s Olympics, all of the medalists in the men’s marathon, regardless of brand sponsorship, all wore the same shoe. It’s not just in the marathon: later that year, Joshua Cheptegei used the shoes to break a 10-year-old record in the 10k using the shoes. The next four runners also wore that shoe (Reuters). Today, all popular running brands have their own version of the Vaporfly, and some are better than others, but they all still emulate the original version of this shoe. The question is: what about these shoes makes you run faster?

Element #1 “Super” foam

The first and most prominent element of these shoes is the foam. The term “super” foam refers to a certain type of polymer, polyether block amide or PEBA. This foam is renowned for its supreme energy return once it is compressed. In the original Vaporfly, Nike claims it offers an 85% energy return, which means 85% of the force pressed into the foam while running is bounced back, helping the runner make longer strides with less effort (Nike.com). It is also a much softer and less dense compound which means it compresses more, but is also much lighter than traditional running shoe foams, which makes it easier to pick up your feet and stride. Every shoe manufacturer has a slightly different formulation of PEBA, but they are all similar. PEBA is also a more expensive compound than traditional foams such as ethylene-vinyl acetate (EVA) and thermoplastic polyurethane (TPU).

Element #2 - Carbon Fiber Plate

Probably the most impactful element of these shoes is the carbon fiber plate contained in them. This plate is a solid piece of carbon fiber that is placed in between two layers of foam in order to give the shoe rigidity. It acts similar to a spring that is bent when your foot bends during the stride, then attempts to return to its original flat shape, giving you a boost during your stride. 

Element #3 - Rocker Geometry 

A rocker geometry usually refers to the shape of the foam in the shoe. Running shoes usually have a curved base in order to allow runners to more easily move through their stride. If they were flat, they would feel clunky and would not be easy to run in. The biggest difference between these racing shoes and regular running shoes is the aggressiveness of the rocker shape. The more aggressive it is, the more you feel like you are falling forward, which helps you turnover your legs quickly. These shoes do not feel good for walking, as the rocker is too aggressive and makes you want to run instead. 

References

Cut in half: New Balance FuelCell SuperComp Elite v4 Review (2024). (2024). RunRepeat - Athletic Shoe Reviews; RunRepeat.com. https://runrepeat.com/new-balance-fuel-cell-super-comp-elite-v-4

Hoka Cielo X1. (2024). Https://Www.hoka.com/En/Us/Race-Shoes/Cielo-X1/1147910.Html?Dwvar_1147910_color=BCQ.

Hoka Clifton. (2024). Hoka.com. https://www.hoka.com/en/us/mens-everyday-running-shoes/clifton-9/1127895.html

Hoogkamer, W., Kipp, S., Frank, J. H., Farina, E. M., Luo, G., & Kram, R. (2017). A Comparison of the Energetic Cost of Running in Marathon Racing Shoes. Sports Medicine, 48(4), 1009–1019. https://doi.org/10.1007/s40279-017-0811-2

Nike Flyknit. (n.d.). Nike.com. https://www.nike.com/zoomx

Staff, R. (2020, January 24). Factbox: Nike’s Vaporfly running shoes and tumbling records. Reuters. https://www.reuters.com/article/technology/factbox-nikes-vaporfly-running-shoes-and-tumbling-records-idUSKBN1ZN0NH/

Wamala, Y. (2023, May 30). Demystifying Running Shoe Foams: The Runner’s Guide to PEBA, TPU and EVA | Supwell. Www.supwell.io. https://www.supwell.io/supbeat/demystifying-running-shoe-foams-the-runners-guide-to-peba-tpu-and-eva