As a clinical aside from Hookes Law issues and stretching springs in series....Hip extension is a pre-requisite for IT stretching for ITBFriction Syndrome. This will alter the role of the lateral stabilisers of the pelvis and (maybe) allow the TFL / Glut Medius to modify their function. If their function can be modified then the changes (if any) gained by stretching may be maintained. Cheers Garry. %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%