Question about physio ball and WW technique

Body: 

Hi Ladies,
Just a question re: use of physio ball or fit ball. I would love some input from Christine or Louise, but others may have opinions or experience which I would also welcome.

It pertains particularly to sitting on the ball....ie. as a substitute for using a chair.
Does this work cohesively with WW technique/posture?
Is it a good idea?

Many thanks
Lindy

Forum:

I say go for it- if it bothers you- leave it.

I think they are great, as long as you use one that is big enough and it is well enough pumped-up so that your thighs are horizontal, or slightly sloping downwards, and at the correct height for your keyboard and screen.