Examining Psychosocial Mediators of Exercise Behavior

描述(申请人提供)：缺乏运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体力活动水平。研究人员假设，基于理论的干预通过改变被认为对行为改变很重要的理论结构(即潜在的中介)，如自我效能感(即对一个人进行身体活动的能力的信心)，有效地影响身体活动行为。不幸的是，以前的研究普遍未能按照主要行为科学家和统计学家的建议，使用适当的统计中介分析来充分测试理论结构的中介效应。本研究的目的是考察基于跨理论模型(TTM)和社会认知理论(SCT)的理论结构的中介效应。我们建议的研究将解决以前研究的方法、测量和统计方面的局限性。我们将420名久坐的健康个体随机分配到基于理论的体力活动干预组或接触控制组。体力活动行为和潜在的调解人将在12个月内每月进行评估。我们假设，基于TTM和SCT的结构(即行为过程、认知过程、自我效能感和决策平衡)将在群体分配(干预与接触控制)与身体活动行为之间起中介作用，这样，当控制中介时，相对于接触控制组的干预对身体活动行为的影响将减弱。我们还将审查特定调解人对不同人口群体(例如年龄、性别)的重要性，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，以便不仅向政策制定者告知在我们的研究范围内提供干预的成本，而且还估计提供干预的每个组成部分(即调解人)的成本。我们的分析将估计未来精细化干预措施的成本，这些干预措施包括影响本研究中介体和体力活动的那些积极成分。总之，我们拟议的研究将确定哪些介体(即理论结构)对于增加体力活动最有效，这将对公共健康产生重要影响，因为这可能会导致更有效和更低成本的干预措施。

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.