The Bill Hartman Podcast for The 16% - Season 11 - Number 2 Podcast
You have to have anterior expansion available to create internal rotation. So if you were compressed anteriorly, you would not have any internal rotation available to you in regard to extremity motion. Let's use the shoulder as an example. If your sternum was compressed downward, you would not have internal rotation available to you. Here's how it works, and I think this is going to answer your question. So let's say you have a legitimate up pump handle, meaning normal expansion anteriorly. As you perform internal rotation, what is actually happening is you are creating the compression by the rotation, and the pump handle is actually going down as you perform the range of motion. Think about twisting a towel—when you twist a towel, it starts expanded and the more you twist it, the tighter the towel gets. Imagine picking up your arm and that being the twisted towel. You're twisting the arm into internal rotation. You have to start with the expanded representation because as you twist, that expansion disappears. That's where the range of motion stops—when you hit the point of compression.
anterior expansioninternal rotationpump handleshoulder mechanicscompression