Kangoo Jumps Rebound Shoes..How Do They Work? The Patented Spring System (Referred To As IPS Or Impact Protection System) Compresses With Each Step To Absorb The Impact Of Athletic Activity That Can Cause Discomfort To Joints When Performed In Traditional Exercise Trainers On A Hard Floor. See How Only The Middle Of The Boot Is Attached To The Spring Therefore As You Bounce, The Spring System Beneath Compresses Taking The Impact Instead Of Your Joints. Because Of This You Can Bounce Harder With