A decent explanation but you have to admit there should be more detailed studies on the angles of force used and what is actually being affected in terms of joints, tendons, ligaments, etc. All guesses should be eliminated as much as possible in future studies or the filed won't be taken seriously by the orthodox medical community.
There are adjutments that can be done in the hips. However, keep in mind that the hip and shoulder joints are different. They are ball and socket joints. Other therapies such as stretching, myofasical release, and exercise help too.