Children do not acquire adequate amounts of physical activity (PA), there for it is important to identify opportunities to increase PA. The purpose of this thesis is to characterize PA during the school day, and to determine the effectiveness of a short term recess PA intervention. Children from two schools (N=75, ages 7-10) wore pedometers for five days. A subset of subjects (N=17) also wore accelerometers. Step counts were recorded 9-10 times/day to obtain PA information for six daily periods. Males were more active than females (P<0.001, 12.331, 9439 step/day respectively). Recess contributes 30.6% of daily step counts, while PE contributes 17.2%. Sex, period duration, weather and location of PA period all were factors for PA. The intervention was effective in increasing PA by a mean 985 (±1808) steps/day (P<0.05). Recess is window of opportunity in which to improve on PA and pedometer interventions are effective in this area.