ABSTRACT
Quantitative studies of human motion have typically focused on properties of the average motion, and their fluctuations were considered noise. Recent publications (for example, Davids et al., 2006) found evidence that the alleged noise, called motion variability, contains important information useful to characterize mature motor skills and healthy states. Motion variability is always present in healthy human beings and even Olympic athletes show motion variability despite several years of intense training of specific movements. Lack or excess of variability are now understood as a deficiency in motor skills.
