Examining Psychosocial Mediators of Exercise Behavior

描述（由申请人提供）：缺乏身体活动与许多健康问题有关，包括心血管疾病、高血压和癌症的风险增加。尽管久坐不动的生活方式对健康有影响，但只有25%的美国人达到了推荐的身体活动水平。研究人员假设，基于理论的干预措施通过改变被认为对行为改变很重要的理论结构（即，潜在的介质），如自我效能（即，对身体活动能力的信心）。不幸的是，以前的研究一般都没有充分测试的中介作用的理论结构，使用适当的统计中介分析的建议，领先的行为科学家和统计学家。我们的应用程序的目的是检查的中介作用的理论结构的基础上的跨理论模型（TTM）和社会认知理论（SCT）。我们提出的研究将解决以前研究的方法，测量和统计局限性。我们将420名健康的久坐者随机分配到基于理论的体力活动干预组或接触控制组。将在12个月内每月评估身体活动行为和潜在介质。我们假设基于TTM和SCT的结构（即，行为过程、认知过程、自我效能和决策平衡）将介导组分配（干预与接触控制）和身体活动行为之间的关系，使得当控制介导物时，相对于接触控制组，干预对身体活动行为的影响将减弱。我们还将研究特定调解人对不同人群的重要性（例如，这将有助于为这些群体制定更有效的干预措施。最后，我们将进行成本分析，不仅告知政策制定者在我们的研究中提供干预措施的成本，而且还估计提供干预措施每个组成部分的成本（即，调解员）。我们的分析将估计未来改进干预措施的成本，这些干预措施包括影响本研究中介质和体力活动的活性成分。总之，我们提出的研究将确定哪些介质（即，理论构建）对于增加身体活动最为有效，这将对公共卫生产生重要影响，因为这可能导致更有效和成本更低的干预措施。

DESCRIPTION (provided by applicant): Physical inactivity is related to many health problems including increased risk of cardiovascular disease, hypertension, and cancer. Despite the health consequences of a sedentary lifestyle, only 25% of Americans meet the recommended levels of physical activity. Researchers postulate that theory-based interventions effectively influence physical activity behavior by changing theoretical constructs believed to be important for behavior change (i.e., potential mediators), such as self-efficacy (i.e., confidence in one's ability to be physically active). Unfortunately, previous studies have generally failed to adequately test the mediating effect of theoretical constructs using appropriate statistical mediator analyses as recommended by leading behavioral scientists and statisticians. The objective of our application is to examine the mediating effect of theoretical constructs based on the Transtheoretical Model (TTM) and Social Cognitive Theory (SCT). Our proposed study will address the methodological, measurement, and statistical limitations of previous studies. We will randomly assign 420 healthy sedentary individuals to either a theory-based physical activity intervention or a contact control group. Physical activity behavior and the potential mediators will be assessed monthly over 12 months. We hypothesize that constructs based on The TTM and SCT (i.e., behavioral processes, cognitive processes, self-efficacy, and decisional balance) will mediate the relationship between group assignment (intervention vs. contact control) and physical activity behavior, such that the effect of the intervention on physical activity behavior relative to the contact control group will be attenuated when controlling for the mediators. We will also examine the importance of particular mediators for different population groups (e.g., age, gender), which will help to create more effective interventions for these groups. Finally, we will conduct a cost analysis to not only to inform policy makers of the cost of delivering the intervention within our study but also to estimate the cost of delivering each component of the intervention (i.e., mediator). Our analysis will estimate the cost of future refined interventions that incorporate those active components that affect the mediators and physical activity in this study. In summary, our proposed study will identify which mediators (i.e., theoretical constructs) are most effective for increasing physical activity, which will have an important public health impact given that this will likely lead to more efficacious and less costly interventions.