Shoe Lab

What is Shoe Lab?

Shoe Lab allows you to estimate the direct effect of footwear on running economy (RE). The Shoe Lab 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 smaller energy.

Is footwear important for RE?

Yes!

Footwear technology has changed over the preceding decade. Traditional footwear technologies (TFTs), - all available shoes prior to 2016 used TFTs - are not considered to have significantly different effects on RE. Runners selected footwear based on broad design features (e.g., a race shoe or a training shoe) and comfort. However, Advanced Footwear Technologies (AFTs) - which have been available since 2017 - are known to significantly improve RE compared to TFTs and have revolutionized competitive distance running. AFTs have been used in world record breaking performances across a range of distances from 5k up to the Marathon.

What is the mechanism that causes footwear to improve RE?

AFTs differ from TFTs in several important ways, the key ones being they have thicker and more resilient midsoles, and they typically contain a curved carbon fiber plate. Both midsole properties and carbon fiber plates are believed to contribute to improved RE.

Midsole properties affect the foam’s capacity to act as a spring. The midsole therefore affects the cost of cushioning and the energy returned during the propulsive phase of ground contact. Both of these effects directly influence COM energetics.

A curved carbon fiber plate increases the longitudinal bending stiffness of footwear which reduces the energy lost at the ankle and foot – especially at the metatarsophalangeal (MTP) joint. However, a stiffer carbon fiber plate is not always optimal. Studies indicate an optimal stiffness exists for each person based on individual body size and biomechanics. Carbon fiber plates therefore indirectly affect COM energetics.

The lower limb biomechanical variables mediating the relationship between footwear properties and RE have not been identified. However, to quantify the mediating effect of biomechanics first requires a theoretical model which can differentiate between the direct effect of footwear and the indirect effect of biomechanics.