This longitudinal study, following children's development over three years, examines the developmental trends in the processes underlying perceptual-motor behaviour. Entry into the study was at first year of primary school, at age 6. The study has three aims: (1) to obtain developmental trends in kinaesthesis and motor-programming processes; (2) to examine the relationship between slow kinaesthetic and motor development; (3) to establish the effect of accelerated kinaesthetic development and prevention of perceptual-motor dysfunction (clumsiness). The results to date show that over 60% of children entering primary school have not developed the kinaesthetic ability necessary for the acquisition and learning of educationally demanded motor skills. Kinaesthetic development is accelerated spontaneously in some children as a response to educational demands; in others a single exposure to kinaesthetic input triggers significant improvement. In the remaining 17% kinaesthetic training can alleviate the kinaesthetic dysfunction. At age 5-6 years only 25 children (8.1%) performed the Perceptual-Motor Abilities Test at levels indicative of perceptual-motor dysfunction. Of these, 13 children (4.2%) were identified as having motor difficulties. These low incidence rates indicate that a low level of kinaesthetic ability has no effect on general motor function at the beginning of schooling, and that only when competence in complex motor skills is expected, from the third year of schooling, does perceptual-motor dysfunction (PMD) become manifest.