Here is an example of a foam roller abdominal crunch. There are several ways to execute a foam roller abdominal crunch. You can place the foam roller along your spine and crunch or as in the video clip, you can lay the foam roller across your upper back and perform a foam roller abdominal crunch that way.  This is a very simplistic and basic exercise on the roller. There are an unlimited amount of stretches and exercises on the foam roller.