The Black Roll is great, because it helps me to be solved remaining blockages and to make soft again and the muscle fibers in specific application. This must, however, deal with a lot of time and let intuition, best in a relaxed atmosphere, and it is certainly worth a bit of experimenting, ie not just lie flat on his back on the role, but also times roll more to the left or right side. If it is then painful, you have time to grit your teeth and / or proceed with a little less pressure. But the success is for me then directly after rolling noticeably.
Also in the calves, where I tend to cramps, contributes to easing the role and thus improved blood flow. - After each self-treatment I did when I was a little stiff earlier, always a great body feeling and less discomfort / pain.
I think the role brilliantly, and I even treat (massage in combination with certain physical exercises), I will include the role in certain cases also in my treatment.