Hi Jimmy,
Just replying to your question last year re: Sarah Key who in fact does use her heel to mobilise the spine and treat patients with back pain- with very good results. She runs courses on her techniques which are held in the UK and Australia. You might want to look at her website for more infomation www.sarahkey.com and she has also written some interesting books- ' Back Sufferers' Bible', 'Back in Action' and ' Body in Action'. Hope this helps you.