What effect do the new shoes have on the running time? Several studies have also shown that the stride length with the Vaporfly increases slightly(partly due to the spring action and the height), which also has a positive effect. This exactly matches the 4% lower energy consumption that Nike claims!īy the way, the height of 40 mm also provides an advantage because the length of the lower leg increases slightly, as it were, which also has a positive effect on the running efficiency. If we divide the difference of 4 J/step for a world class athlete with a stride length of 1.5 m by 666 steps/km and a body weight of 60 kg, we come to a reduction of the ECOR of 0.04 kJ/kg/km. Hoogkamer measured in the laboratory that the Vaporfly’s spring operation was able to return 7.46 Joule of energy per step compared to 3.38 J for the Nike Zoom Streak and 3.56 J for the Adidas BOOST2.

they use multiple layers of viscoelasticpolymers (PEBA) with a thickness of 40 mm.

they use a carbon plate that functions like a spring.

The function of Carbon shoes such as the Nike Vaporfly has been described by Wouter Hoogkamer et al. It was also known from the literature that shoes that use an air-bag and thermoplastic polyurethane foam (such as the Adidas BOOST) can reduce the ECOR by order by 1% because the foam is viscoelastic and returns part of the landing energy. Most race shoes are therefore already very light nowadays, in the order of 200 grams. It has traditionally been known that light shoes have an advantage: in The Secret of Running we have calculated that 100 grams of weight loss provides an advantage of 0.25-1.00 %. How do your shoes affect your specific energy consumption? This part is virtually negligible at low speeds, but with world class athletes it can be 7% or more. Please note that you must correct – even in windless weather – for the power needed to overcome the air resistance. With the introduction of Stryd, it has become possible to easily measure your individual energy consumption by dividing your specific power (Watt/kg) from a training or race by your speed (in m/s): the result of the division is your ECOR in kJ/kg/km. – vertical oscillation (effect not uncontroversial) – stride length and cadence (large strides high frequency) – foot landing (short ground contact, not on heel)

physique (long legs, narrow calves, narrow and flexible hips are better).

The running efficiency covers many aspects, the influence of which are not explicitly known. For example, it is well known that some marathon runners, especially the Kenyans and Ethiopians, have a high running efficiency. The specific energy consumption is NOT the same for everyone and under all circumstances. Is the energy consumption the same for everyone?

This value has now become the universal standard and is also used by Stryd and other authors. We concluded in The Secret of Running that it is very realistic to use the calculation value of 0,981 kJ/kg/km. When we consider that various authors have used different methods and the circumstances have also been different, it is remarkable that all values are close to the average. In chapter 12 of our book The Secret of Running, we have included the following table on the specific energy consumption when running on a hard surface (ECOR in kJ/kg/km). How high is the energy consumption in running? At the end of the article, we will answer the question from the title. A lower ECOR means that you use less energy and can run faster with the same power. In this article, we will provide an overview of the energy consumption in running (the so-called ECOR, the Energy Cost of Running) and the factors that influence this, including the recent development of carbon-plate shoes, such as the Nike Vaporfly. But because the energy consumption with the Vaporfly is up to 4% lower, at that power of 322 Watts he will run about 3-4% faster than 41:30!Įddie’s question did encourage us to review the current knowledge and literature about the influence of running shoes on the race times. So he has to run his fast 10K the power of 322 Watts. We have already informed Eddie that the Critical Power reflects the power of his human engine and therefore does NOT get higher if you wear faster shoes. My question is: what is the impact of Vaporfly on your power? Do you run with the same power faster on the Vaporfly or can you run on a higher power? If it is the last, can you add 4% to your Critical Power?” If I follow Stryd Race Calculator then I can run this 10 km with a Power of 322 and I’ll finish in 41:30. I also have the Vaporfly and I want to use it for the first time for a fast 10 km. The Vaporfly is about 4% more efficient than a regular shoe. Read some articles about the Stryd and the Nike Vaporfly. We recently received the following interesting question from one of our fans, namely Eddie :

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