Spontaneous motility in the first six months of infancy has been examined over the last few decades using both qualitative and quantitative techniques. The major focus of the quantitative research has been to investigate a dynamic systems approach to understanding motor development, and has primarily examined normal development in fullterm infants. Recently, there have been several papers comparing spontaneous kicking in fullterm and preterm infants. These studies were designed to identify developmental differences that may indicate a risk of later motor disability. There has, however, been criticism that the quantitative approach fails to detect developmental differences that are useful in early identification of disability, unlike qualitative approaches which use the principles of Gestalt perception to examine the quality of the total movement pattern in young infants. The current paper describes both qualitative and quantitative techniques and reviews recent studies using motion analysis to compare early motor development in fullterm and preterm infants. New evidence is provided to suggest that the quantitative approach may not only be useful in detecting infants at risk of motor disability, but may also be useful in identifying the underlying processes that determine normal and abnormal motor outcomes.