When it comes to discussing the diagnosis of low back pain (LBP) there are times when it is really hard to put a label on pain because it is hard to say is it one specific thing. Such a blurry diagnosis. In fact 85-90% of people with LBP are in this category making the blurry diagnosis the majority. The O'Sullivan system is a framework that aims to identify the main drivers and mechanisms of pain and dysfunction. Where movement is associated with pain, the classification considers if the movement is protective or maladaptive? This blog is all about this framework, breaking it down step by step, to help others see how using this classification system makes a complex pain disorder less complicated.