Dear Mortondave
Do not worry about cardiac output for a hemiplegic with high BP during trunk flexion, voluntary movement or static abs will not influence autonomic nervous system.

The reason why her trunk goes into hyper extension is not necessarily due to weak trunk flexor but is a pure defensive CNS response affecting biomechanics to alter muscular response.

rajul vasa
working on total solution for stroke with vasa concept.
www.brainstrokes.com