FIRMO: A Sole That Is Stiff Sideways and Free to Flex Forward

Field notes

The proposed system divides the midsole job between a forefoot strut array and a midfoot bridge. The struts are arranged across the shoe’s width and fan along the toe-joint line, with gaps intended to open during forward flexion. A four-layer build leaves foam, outsole compound, and exterior design to the licensee. The page says the parts are glued into an existing midsole cavity and can be supplied without new licensee tooling, while detailed dossier access is request-based.