No matter how well designed, there are no running shoes that allow runners to keep up with cyclists. The bicycle was a key invention that doubled human-powered speed. But what if a new kind of shoe could allow people to run faster by mimicking cycling mechanics?

This is the question my students in Vanderbilt’s Center for Rehabilitation Engineering & Assistive Technology and I explored as we developed a new theory of spring-driven robotic exoskeletons. We came up with a concept for a new type of lower-limb exoskeleton that could allow the world’s fastest human to reach a speed of 18 meters per second or about 40 miles per hour.

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