The pumping of a playground swing from the seated position is modeled using a dumbbell consisting of three masses. The equation of motion of the system when the dumbbell is forced to rock back and forth is obtained. When reasonable approximations for amplitudes are made, the equation of a linear harmonic oscillator with a driving and three parametric terms is obtained. Based on an analysis of this equation using numerical values of the parameters, it is concluded that the pumped swing is a driven harmonic oscillator for small-to-moderate amplitudes. Growth rates and relative phase of pumping and swing motion are determined and discussed. The source of the driving term is traced to the conservation of total angular momentum (motion of the center of mass and motion about the center of mass) about the point of support of the swing.

Community-based prevention marketing (CBPM) is a community-driven framework for program planning, which applies social marketing concepts and techniques to the development of health behavior interventions. Whereas community members who comprise an action committee or coalition set the goals and make programmatic decisions, social marketing provides the planning framework to guide program design, implementation, and evaluation. CBPM has guided successful initiatives to promote physical activity in both youth and adults, to increase safety eyewear use in agricultural settings, and to delay alcohol and tobacco initiation among youth. However, the emergence of evidence-based policy has fostered renewed interest in “upstream” approaches to health behavior change that, in the United States, have included community partnerships as an important tool for policy development. Unfortunately, these community partnerships have had variable success because of the lack of a systematic framework for identifying, selecting, tailoring, and promoting evidence-based policies. We describe the adaptation and application of CBPM to improve community capacity for identifying and promoting evidence-based policies. The resulting framework, CBPM for Policy Development, is comprised of the following eight steps: (1) build a strong foundation for success; (2) review evidence-based policy options; (3) select a policy to promote; (4) identify priority audiences among beneficiaries, stakeholders, and policy makers; (5) conduct formative research with priority audiences; (6) develop a marketing plan for promoting the policy; (7) develop a plan for monitoring implementation and evaluating impact; and (8) advocate for policy change. We provide a description of each step and an examination of the experiences and lessons learned in applying it to youth obesity prevention.

In the United States, community coalitions are an important part of the public health milieu, and thus, subject to many of the same external pressures as other organizations—including changes in required strategic orientation. Many funding agencies have shifted their funding agenda from program development to policy change. Thus, the Florida Prevention Research Center created the Community-Based Prevention Marketing (CBPM) for Policy Development framework to teach community coalitions how to apply social marketing to policy change. The research reported here was designed to explicate the framework’s theory of change. We describe and demonstrate a hybrid evaluation approach: utilization-focused developmental evaluation. The research question was “What are the linkages and connections among CBPM inputs, activities, immediate outcomes, intermediate outcomes, and ultimate impacts?” We implemented a case study design, with the case being a normative community coalition. The study adhered to a well-developed series of steps for system dynamics modeling. Community coalition leaders may expect CBPM to provide immediate gains in coalition performance. Results from causal diagramming show how gains in performance are delayed and follow an initial decline in performance. We discuss the practical implications for CBPM’s developers—for example, importance of managing coalition expectations—and other social marketers—for example, expansion of the evaluation toolkit.

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