Dear Kevin, I agree with you, science is born out of clinical practice. However, too often today, I believe there is a big gap between researchers and clinicians. Nevertheless, I think it is important to understand what we are doing, to ensure Physiotherapists are scientifically based and not just clinically proven. AS with Mckenzie, I think his old hypothesis of disc prolapse has been disproven. If you visit the Mckenzie webpage, his new hypothesis now has integrated with Mulligan's joint positional fault hypothesis. Please keep in mind that these are only hypotheses, and it is a starting point for further scientific research. I guess like any other experiment, if the scientific evidence doesn't support the hypothesis, then you simply change the hypothesis until somebody else disproves it again. Henry*** _________________________________________________________________________ Get Your Private, Free E-mail from MSN Hotmail at http://www.hotmail.com.