Knitting the pain away - science and yarn

A study conducted Royal United Hospital, Bath, suggests that knitting can improve sufferers' experience of chronic pain.

It says more work needs to be done to work out why this happens. It could be  a number of things such as:
rhythmic repetitive movements and their role in meditation and serotonin release; the effect of bilateral  patterns of hand movement on brain maps; automatic movements on rumination; the ‘end product’ and its effect on the reward system; the effect on cognitive function; stimulation from colour, texture and being creative.

I'm particularly curious to find out what is going on because I have osteoarthritis and sometimes experience a great deal of pain. But my anecdotal experience is that knitting in some way improves the experience perhaps by distracting me or perhaps its the medative thing. I'll be following this with interest.