Strengthening Bones By Squeezing Their Fluids

In preparation for my next entry, here is a NY Times article that discusses something I've always suspected about the way bones behave during exercise and movement:
http://well.blogs.nytimes.com/2009/11/11/phys-ed-the-best-exercises-for-healthy-bones/

In my book (pp. 179 - 183), I discuss how using your bones creates forces of stretching, pushing, pulling, twisting, compressing, and bending. Every time you exert any influence or pressure on a bone there is a corresponding change of shape and an accompanying electrical charge, called the "piezoelectric effect." This influences the bones to remodel to accommodate the motion and weight distribution that they are being asked to support. Connective tissues will thicken where support is needed and thin where they need to yield. Minerals will be laid down to allow for support in areas of strain and weight bearing. This is generally how bones are thought to be strengthened by weight-bearing exercise.

This article explains how during the movement of exercise, bones bend, and fluids are squeezed from one part of the bone matrix to another. The extra fluid inspires the cells bathed with it to respond by adding denser bone.

I've been wondering how this applies to my tumor-filled bones. Pain in my sternum, ribs, and clavicle initially immobilized me and prevented me from exercising, but now I think I have more fear of pain than actual pain (I'm talking about the pain in my chest; I still have actual pain in my hands and several joints.) Do I want/need to stir up the matrix of a tumor-filled bone? Will this help my immune system have access to the tumor to break it down? Or will squeezing the fluid through the cancer infiltrated matrix potentially spread it? There is no medical expert who can answer this question, so I just have to live into the answer as I act according to what feels right to me.