The document provides instructions for several stretches to improve back flexibility. It begins by describing an exercise of bringing one knee toward the chest while lying down and holding for 10 seconds before switching legs. Next, it explains how to do an arching back stretch on the floor by lifting the chest and stomach off the ground while inhaling for 15 seconds. Finally, it details a seated stretch where one leg is bent toward the body to stretch the back of the leg and lower back, holding for 10-20 seconds before switching sides.