Also, remember you can also move up and down the shaft with the bar. The closer you get to the base the more you will be doing expressive stretching and as you move up the shaft it becomes more ligamental. Also, varying the size of the bar would also increase intensity. A marker, as seen in the picture could be replaced with something thicker and this would add to lateral stretch. If curvature is an issue one could easily stretch against the curve for lengthly sessions.