The chapter is divided into six sections: First, a brief review of the past 25 years of motor development research, focusing primarily on the style of inquiry and the nature of the dependent variables used. Second, a discussion of the dependent variables that traditionally measures the product rather than the process of movement, and the ways in which their contribution to the description and analysis of movement patterns in children has both helped and constrained progress. Third, the movement studies of children incorporating the ecological perspective. Fourth, research on fetal motor activity is reviewed in the chapter. Fifth, a discussion of periodicity in motor behavior; the ways in which it is measured and its promise in understanding movement behavior is illustrated in the chapter. A sixth and final section summarizes the chapter and comments on future directions and initiatives, one of which is the use of allometry as a technique for studying movement patterns in children.