In 2010, Massachusetts State Department of Early Education mandated that preschools provide a minimum of 60 minutes/day of outdoor playtime for preschool-age children.  Most preschools divide the 60 minutes into two 30-minute time blocks (morning and afternoon) of unstructured free playtime.  This format has proved ineffective at increasing preschoolers' physical activity.  The overall aim of this study is to examine the efficacy of short bouts of structured physical activity versus traditional long bouts of unstructured outdoor playtime on total physical activity and sedentary time during the school day in low socioeconomic status preschoolers in the greater Springfield, MA area.  The intervention for this study will be an age-appropriate Instant Recess for preschool-age children called "Tutti Fruitti Instant Recess."