youth and school-related policies and practices that enable or impede those behaviors is inadequate.

•  An adequate description of the current status of and monitoring of changes in students’ school-related physical activity behaviors currently is not possible. Public health and education surveillance and research need to be enhanced so that the impact of efforts to increase students’ physical activity can be monitored.

•  Policies are and will be important in creating an atmosphere in schools that enables, facilitates, and encourages children to be more physically active. Less clear are the factors that create an effective policy. An understanding is needed of what facilitators (e.g., funding, promotions, awards) and enforcers (e.g., less funding, job security) lead to policies that are fully implemented.

As discussed in further detail throughout this chapter, few children in the United States, probably no more than half, meet the currently recommended standard of at least 60 minutes of vigorous- or moderate-intensity physical activity daily (CDC, 2012b). In addition, the proportion meeting the standard declines with age, with more elementary school children than middle and high school students achieving the goal. Boys are more likely than girls to meet the recommendation. Finally, it can be said with reasonable certainty that during the past 30-40 years, probably even longer, the volume and intensity of daily physical activity among youth have gradually declined.

It is also known that because children and adolescents spend so many hours at school, school-related physical activity must be a large contributor to overall physical activity among youth. Not known, however, is exactly how large the overall contribution is or the contribution of each segment of the school day—transportation to and from school, physical education, recess, classroom time, and before- and after-school activities. It is known that over the past 40 years the proportion of children walking and biking to school has declined substantially; otherwise, there are at best rough estimates of the current physical activity behaviors, recent changes, or long-term trends associated with each of these segments of the school day.

Guidelines, recommendations, and policies from all levels of government (federal, state, district, local) and from various organizations (e.g.,

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