Physical activity in childhood is a key component for promoting lifelong health. Current guidelines for school-age children recommend at least 60 minutes of moderate-to-vigorous physical activity (MVPA) daily, with at least 30 minutes occurring during the school day in part because of its positive impact on academic performance. The majority of daily physical activity often occurs during the school day; however, children from low-resourced schools often face a number of social and environmental barriers to meeting these recommendations. Thus, understanding the patterns and amount of physical activity accrued across the school day, along with identification of opportunities for school-time physical activity engagement, provides important information for educators in helping children meet their physical activity goals. This study examined school-day patterns of physical activity and sedentary time among pre-K and elementary schoolchildren from lower-income urban elementary schools to identify opportunities for better integrating physical activity across the school day. (author abstract)