Equivalent Footwear Mass Explorer

What is Equivalent Footwear Mass Explorer?

Equivalent Footwear Mass Explorer is an exploratory app that allows you to estimate the direct effect of footwear on running economy (RE). The Equivalent Footwear Mass Explorer app can be found here.

What is RE?

RE is a key determinant of distance running performance and is defined as the energy cost to move the centre of mass (COM) at a given race pace. A more economical runner uses less energy.

Is footwear important for RE?

Yes. Footwear can meaningfully influence running economy (RE), and its importance has increased substantially over the past decade. With traditional footwear, differences in RE between models were generally relatively modest, and runners often selected shoes according to broad design categories, such as racing or training shoes, as well as factors such as comfort and fit.

The introduction of Advanced Footwear Technologies (AFTs) from around 2017 changed this landscape. AFTs typically combine lightweight, highly resilient midsoles with increased stack height and stiffening elements such as carbon-fibre plates. These shoes have been shown to improve RE compared with traditional footwear, although the magnitude of the benefit varies considerably between shoes and between individual runners. AFTs have subsequently become widespread in competitive distance running and have been worn in world-record performances across distances from 5 km to the marathon.

What is the mechanism that causes footwear to improve RE?

Advanced Footwear Technologies (AFTs) typically combine lightweight, thicker and more resilient midsoles with stiffening elements such as curved carbon-fibre plates. These features can improve running economy (RE) through both direct mechanical and biomechanically mediated effects.

Midsole properties influence cushioning, energy storage and energy return, while lower-density foams can provide these benefits without substantially increasing shoe mass. Carbon-fibre plates increase longitudinal bending stiffness and alter foot and ankle mechanics, although the optimal stiffness appears to vary between runners.

It is therefore useful to view footwear effects on RE as a combination of the shoe’s direct mechanical properties and the way an individual runner biomechanically responds to them.

More information about these ideas can be found here and here