Two new methods that accurately analyze the displacement velocity of the center of pressure (COP) in order to diagnose postural control systems are presented: a wavelet analysis method and a method that analyzes the distribution of COP displacement velocity. Both methods could easily detect a transient but significant phenomenon in a series of COP swings. Recovery training based on diagnoses made by these methods should enable individuals to maintain effectively their postural control systems. As it is important to prevent potentially fatal accidents from falls involving elderly people, the two methods presented have much to contribute to aging societies in developed countries.