When I perform the is trick, I have to be sure that my set up is precise. I have to make sure that the pole crosses my back where it is most flexible. Next I try to wrap my torso as far around the pole as possible before I grab my free leg. Once I have the leg, I focus on pulling my knee behind me (working the hip flexor), then extending the leg. If I don’t get my leg behind me, it won’t straighten.