Implications of a dynamical systems approach to understanding infant kicking behavior. Implications of the dynamical systems approach to understanding movement dysfunction in infants are discussed. Traditional theories of motor development attribute changes in movement to the hierarchical maturation of the central nervous system. The dynamical systems approach emphasizes that movement self-organizes as the result of the interaction of the participating subsystems in developmental and real time. In this article, I discuss, from the theoretical perspective of the dynamical systems approach, the organization of leg movements in low- and high-risk preterm and full-term infants, developmental changes in movement in low-risk preterm infants from 34 weeks' gestational age to 40 weeks' postgestational age, and differences in movement between low-risk preterm infants at 40 weeks' postgestational age and full-term infants. Preliminary data on high-risk preterm infants are presented. Based on these data, the necessity to review and reinterpret traditional concepts of motor development is explored. Suggestions are offered and questions posed on how the dynamical systems perspective may influence the practice of physical therapy in the evaluation, and treatment of infants at risk for movement dysfunction. 