A device for mobilizing a joint includes a flat, planar substrate having a first face and an opposing second face. A first longitudinal side extends between the first face and the second face. A second longitudinal side extends between the first face and the second face, distal from the first longitudinal side. A mobilization portion extends above the first face and includes a first convex rib extending parallel to the first longitudinal side, a second convex rib extending along the second longitudinal side and parallel to the first convex rib, and a valley extending between the first convex rib and the second convex rib along a longitudinal centerline of the flat, planar substrate. A cavity extends above the first face. The cavity is defined by an opening between the first face and the mobilization portion and is sized to receive a bladder.
