FitFlop Footwear’s doctor-developed patent-pending Microwobbleboard™ technology is built into a multi-density midsole that makes your legs muscles work harder than they do in standard-style trainers, sneakers or shoes. Created by Senior Lecturing Biomechanist Dr David Cook and Darren James at London's Southbank University, all you have to do is wear them and you get a workout while you walk ™.