Looking at several of your threads and the theme is using Python to move bits of the body around and then exporting the resulting mesh.  If it was me, I would take the model use the morph brush to move parts of the chest outwards and then use the resulting dial to move the chest in and out along the timeline.  The advantage is the mesh stays together with the rest of the body and you can make bits expand more than other areas.  Then use your python to change the value of the morph channel so that it moves i and out.

Poser 5, 6, 7, 8, Poser Pro 9 (2012), 10 (2014), 11, 12, 13