The theory of functional kinetics has evolved from practical experience, developed during the process of treating patients and teaching students. It is important to see and feel what actually happens when the human body is in motion, and to recognize when and why deviations occur. The perception of deviation presupposes that we possess a mental image of normal movement and consequently an ability to recognize deviations from it. It follows that the theory of functional kinetics cannot be derived from pathological symptoms. Pathological symptoms cannot provide the model because they are a deviation from a healthy state, and as it is our aim to pursue a form of physiotherapy proper to the natural human being, it is only reasonable to choose the normal movement patterns of a healthy human being as our model.