Physical activity (PA) is important for children’s growth and development and for their current and future health. Schools, especially during physical education (PE), are important locations for children to accrue PA. The purpose of this study was to assess the PA levels of preschool children during structured PE lessons and to evaluate the impact of selected characteristics (e.g., lesson context, length, and location; teacher behavior; class size; activity area density). Trained observers used SOFIT (System for Observing Fitness Instruction Time) to assess 90 structured PE lessons taught by 25 different teachers. Intact classes (n = 5 to 6 and representing 3 different grade levels) in 4 selected preschools were observed on 4 days over a 4-week period. Overall, children engaged in moderate-to-vigorous physical activity (MVPA) 49.9% (SD = 15.7) of lesson time and there were differences in MVPA% among the four preschools, by lesson context, and by teacher behavior. There were no significant differences in MVPA% either between indoor (n = 69) and outdoor (n = 21) lessons or among the 3 grade levels. Even though the lessons approached the 50% MVPA guideline, the brevity of them left children far short of recommended daily amounts of PA. Future studies should investigate how preschools can increase on-campus opportunities for PA both during PE and throughout the school days. Copyright © 2015 by authors and Scientific Research Publishing Inc.

Physical activity (PA) is important for young children in achieving positive health outcomes and there is growing evidence suggesting that PA and fitness play an important role in children’s brain development and academic performance. Studies of preschool children typically show that few meet recommended daily PA levels. Meanwhile many preschoolers worldwide attend preschools, but little is known about their on-campus PA or the factors that influence it, especially during classroom sessions. The purpose of this study was to use a validated instrument to conduct a micro-analysis of student PA levels, lesson contexts, and teacher prompts for PA during classroom sessions. We assessed these factors during 165 classroom sessions taught by 25 teachers in four preschools. The sessions occurred prior to (PRE-PE) or following the PE lessons (POST-PE) that we described in an earlier paper (Chow et al., 2015) . Children spent classroom time primarily sitting (76%) and standing (13%), while engaging in PA (mostly of low or moderate intensity) 11% of the time. PA occurred mostly during lesson transitions and music time. Overall, boys were more active than girls (MVPA% = 12.1 vs. 8.8), and teachers rarely promoted either in-class or out-of class student PA. The study contributes to the limited literature on PA and its related contexts in preschools. The results have implications for providing pre-service and in-service teacher education related to the importance of PA and how to implement it. Expanded surveillance studies are recommended. In addition to using questionnaires and accelerometers or pedometers to assess PA, the studies should include observation methods so that important on-site and potentially modifiable contexts can be assessed directly. Copyright © 2015 by authors and Scientific Research Publishing Inc.