Lightweight foam that would break down SO QUICKLY, I can't even imagine. Nike has become the shoe one wears just for the Swoosh. They look cool but almost from the moment one puts them on they are a disappointment. The foam base has no reinforcement-no good quality rubber on the bottom to keep the foam from breaking down. Nike quality has diminished so rapidly lately that scores of their shoes can be found at discount name-brand stores for 50-60% less. Logo peels easily and they squeaked with every step I took! Nike used to be the only shoe I wore for workouts because of their fit and quality but I'm going to have to stick with ugly, EXCELLENT BROOKS shoes. They're worth every penny. These Nike's were just so disappointing. They appear to be sweat-shop produced shoes.