Have you spotted that soft cylinder-shaped object at the gym and wondered what it was for? It's a foam roller, a self-myofascial release (SMR). Used by many athletes, it decreases tissue tension, lengthens muscles, and loosens restricted fascia, which is a sheet of fibrous connective tissue made of collagen that surrounds muscles. May 11th is National Foam Rolling Day, so here are five ways using one can help you out.