摘要：Objectives. We examined whether schoolyard improvements led to increased physical activity levels among both boys and girls and assessed the aspects of schoolyard design that have an impact on physical activity. Methods. In a quasi-experimental research design, 6 schools with renovated schoolyards and 3 control schools were divided into activity areas. We calculated measures of children's physical activity by area during school hours as well as after-school hours. Results. The volume of schoolyard use was significantly higher at schools with renovated schoolyards than at control schools, and students were significantly more active at these schools. Also, activity levels were significantly higher among both boys and girls in certain schoolyard areas, such as those with soft surfaces. Conclusions. Because few public elementary schools in the United States provide daily physical education or its equivalent for all students throughout the school year, noncurriculum approaches to increasing children's physical activity are important. Renovated schoolyards increase the number of children who are physically active, as well as their overall activity levels, and reduce sedentary behaviors. The percentage of children who are overweight or obese has increased rapidly over the past few decades. 1 , 2 The change in norms within US culture has led to higher consumption of fatty and calorie-rich foods and an increase in sedentary behavior. To combat this change, new norms must be established that include increases in physical activity. To ensure that future generations are spared the cost of obesity, this normative change must start during development, in childhood. According to most recent recommendations, children should participate in at least 60 minutes of moderate to vigorous activity every day. 3 Considering the sedentary lifestyles many children lead, the majority of children do not meet these recommendations. 4 With the average child spending 1300 hours at school each year, 5 schools have the potential to provide numerous opportunities for the promotion of physical activity, 6 – 10 including physical education, recess, intramural programs, interscholastic sports, and access to school physical activity facilities during and outside of school hours. 11 – 15 Although school time allocated for physical activity has been reduced, 16 schools are still healthy spaces for students 17 , 18 and are the opportune setting in which to increase physical activity. According to the Centers for Disease Control and Prevention, however, only 2% of elementary schools provide daily physical education or its equivalent during the entire school year for students in all grades. 19 Although there is an obvious need to increase the amount of school time devoted to physical activity, noncurriculum approaches to increasing children's activity levels may be important as well. 16 For example, providing access to recreational facilities during breaks in the school day (e.g., lunchtime and recess) and outside of school hours can potentially encourage children to engage in physical activity. 20 – 28 Several studies have shown that concentrating on individual behavior changes to combat obesity can be effective; however, these changes are typically not sustained and have little true effect on people's behavior. 3 , 29 , 30 Thus, social ecology and the built environment have been focal points for obesity prevention. With respect to environment–behavior research, socioecological theory explains human activity as a function of interactions between people and their environments. 31 , 32 Environments include a range of behavior settings that are seen to provide, to different degrees, opportunities for desired behaviors. Thus, environments exert probabilistic influences, making certain behaviors more or less likely. Changing children's school environment can alter their activity levels and their exposure to physical activity. 33 One school environment change that has been shown to increase physical activity is upgrading and changing schoolyard spaces. The available quantitative and qualitative research supports the hypothesis that improvements in schoolyard design, including schoolyard markings (e.g., painted asphalt) and renovations, are accompanied by increases in physical activity. 22 , 23 , 34 – 36 However, research on the effects of schoolyards on children's physical activity is sparse, and most studies have been limited in both the number of children observed and the number of sites evaluated. In addition, few studies have divided schoolyards into individual components in an attempt to understand which components encourage and discourage physical activity. We compared renovated schoolyards with nonrenovated schoolyards at elementary schools in the metropolitan Denver area to assess whether specific schoolyard improvements increase physical activity. In addition, in an effort to understand gender-specific effects of schoolyard equipment components, we compared different components to determine those that hinder physical activity among boys or girls and those that provide increased opportunities for physical activity for all children.
