Its not that I've dismissed it out of hand but the chiropracter suggested that swiss ball stuff would be more specific and effective in the long-term, especially if done in a small group where the feedback is better. He did say that pilates and yoga would be alright as well but perhaps not quite as specific and also they tend to be larger classes. Thanks for the info though. I might get back to you about Zaff's. Is that the class that pretty much everyone in sheffield went to for a while last year?