How Technology Is Used To Engineer Faster Running Shoes

Before the 2024 Olympic marathon, Canadian runner Malindi Elmore visited Saucony’s Human Performance and Innovation Lab near Boston to test four pairs of running shoes. Engineers attached 80 reflective markers to her body and shoes, fitted her with a mask and air tube to measure oxygen consumption and had her run at 11mph on an instrumented treadmill, according to Sports Business Journal. The equipment recorded her movements, the forces involved in each step and how much oxygen she used in each pair.

Modern racing shoes are designed to improve running economy and energy return. Engineers use motion capture, force measurements and physiological testing to investigate how different designs affect runners. By comparing movement patterns, mechanical measurements and energy use, they can assess which design features might improve performance.

Watching Every Step With Motion Capture

Reflective markers allow cameras to track a runner’s movements in three dimensions. Software processes the data so engineers can analyse joint angles and how the body moves throughout each step. Saucony’s setup used eight Vicon cameras to track the markers, with the motion data synchronised with measurements from the treadmill.

Researchers at the University of Colorado Boulder used similar technology in a 2018 study published in Sports Medicine. Ten competitive male runners wore reflective markers while researchers used 3D motion capture to examine their joint mechanics in three different racing shoes. They found that runners wearing the Nike Vaporfly 4% prototype used less muscular effort around the ankle, while the shoe’s stiffness reduced the work required from muscles that stabilise the toe joints. The researchers didn’t find differences in knee or hip joint mechanics between the shoes.

Force Plates And The Ground Pushing Back

Every time a foot lands, it pushes against the ground and the ground pushes back. This is known as the ground reaction force. Force plates measure these forces in different directions, while instrumented treadmills can record them continuously as a runner moves.

Synchronising force measurements with motion-capture footage helps researchers examine the forces involved in each step alongside the runner’s movements. Pressure sensors and instrumented insoles provide further detail about how pressure is distributed across the foot, including the heel and forefoot. Engineers can use this data to investigate how a shoe’s cushioning and structure respond during landing and push-off.

A force plate records the forces beneath a runner’s foot, but it can’t tell engineers whether the shoe feels comfortable. That’s something Elmore can report herself.

Testing The Human Engine With A Mask

Mechanical measurements show how a shoe interacts with the ground, but they don’t reveal how much energy a runner uses to maintain a particular pace. For that, researchers measure the body’s response to exercise.

A runner wears a mask connected to a metabolic cart, which measures oxygen consumption and carbon dioxide production. Researchers can monitor heart rate alongside these readings, while some studies also measure blood lactate to assess the body’s response to exercise.

Running economy describes the energy required to maintain a given running speed. Researchers commonly assess it by measuring oxygen consumption under controlled conditions, with lower oxygen consumption at the same pace indicating better running economy.

In the 2017 Colorado study, 18 high-calibre male runners performed treadmill trials in three racing shoes: Nike’s Vaporfly prototype, the Nike Zoom Streak 6 and the Adidas Adizero Adios Boost 2. The Vaporfly prototype reduced the energetic cost of running by an average of around 4% compared with the other shoes. That finding inspired the Vaporfly 4% name.

The mechanical and physiological tests measure different things. Force measurements and motion capture show how the runner moves and the forces involved, while oxygen measurements reveal how much energy the runner uses. Saucony combined biomechanics, physiological measurements, mechanical testing and Elmore’s feedback to help select her Olympic marathon shoes.

Turning Lab Data Into Faster Shoes

Engineers use these findings to refine a shoe’s geometry, midsole foam, stiffness and overall construction. They can also test the shoe itself by applying force to its sole and measuring how much mechanical energy it returns.

In the Colorado researchers’ 2018 follow-up study, the Vaporfly’s foam cushioning returned 87% of the mechanical energy stored during testing. The researchers also found that the carbon-fibre plate returned relatively little energy by itself, estimating that the foam accounted for roughly 50 times more of the energy savings.

Carbon-fibre plates still play a role in the shoe’s design. They increase bending stiffness, changing how the foot works as it pushes against the ground. The researchers found that the Vaporfly’s performance came from a combination of the foam, plate and their effects on running mechanics, rather than one component working alone.

Weight is another factor. Research has found that shoe mass affects the energetic cost of running, although the effect depends on the shoe and testing conditions. Removing weight at the expense of useful cushioning or other performance features can undermine the design.

Engineers test successive prototypes to compare their performance and adjust the construction. A shoe that performs well in a laboratory but leaves a runner uncomfortable halfway through a marathon needs more work.

Why Engineers Keep Testing New Prototypes

Motion capture, force measurements and physiological testing give shoe designers different sets of data to work with. Engineers can compare how a runner moves in each prototype, measure the forces involved and check whether the runner uses less energy at the same speed. Those results help guide the next round of design changes.

Developing faster running shoes takes repeated testing, with engineers adjusting the foam, shape, stiffness and weight to see how each change affects performance. The goal isn’t simply to build a shoe that bounces back more energy, but one that helps runners maintain their pace while using less of it. Behind every new racing shoe is a lot of data, a fair amount of trial and error and plenty of miles on the treadmill.