This article addresses exemplary differences between preschools with systematic physical activity (PA) programmes and preschools without PA programmes in Germany. Two preschools from each group were visited in the context of a focused ethnographic observation to examine the educational practice, PA and social behaviour of preschool children. The observation showed that children engage in PA in preschool under certain conditions (e.g. a structure providing a wide range of PA offerings that can be selected according to interest). Potentials of PA promotion can also be seen in the areas of rule-teaching and the promotion of self-confidence in children. A structure-providing policy in conjunction with the provision of exercise rooms and the promotion of children's independence seem to have special influence on the social behaviour of children. Promoting children's independence serves to strengthen the children's sense of self-efficacy and may contribute to improving their social skills and reducing the burden on teachers.