Right now, running shoes get better every year. What if they could get better every day?

The primary deliverable of this project is a Variable-Stiffness Treadmill (VST) for biomechanics researchers studying human walking patterns, able to dynamically simulate preset non-linear stiffness curves, maximizing a runner’s energy-conversion efficiency and facilitating the development of next-generation running shoes.

It is recognized that an “optimal” stiffness value is subject to user-to-user variation. While currently available VSTs, i.e., the AdjuSST, are capable of covering certain ranges of stiffness, these VSTs cannot simulate non-linear stiffness profiles, which could be instrumental in reaching this optimal stiffness profile. This problem is solved by our VST.

The VST's variable stiffness technology is accomplished through changing the effective length of two steel cantilever beams, which act as a spring when the user is running on the treadmill. By changing the effective length of these beams as the user steps down, the treadmill can change stiffness in the middle of a step, resulting in a non-linear stiffness profile.