Discussion
The Community Walks study addresses a gap in the literature to test multilevel interventions in low-income populations and is nearly unique in its focus on this population, on a layered multilevel design, and on walking as the main form of physical activity. The environmental level intervention will be delivered by community residents trained as HLAs for leading walks using newly designed and marked walking trails around the development. Among residents randomized to the I and E+I condition, we will enroll interested residents to a more intensive individual level eHealth phone intervention to further promote motivation and self-efficacy for physical activity.As described by Hall and colleagues, a continuum exists ranging from fundamental multilevel research to multilevel intervention research [The interviews we have planned at the conclusion of the trial will help us understand barriers and facilitators to intervention reach, adoption, implementation and maintenance, which will inform future intervention efforts. Other research teams have also included qualitative methods of intervention evaluation, including participatory evaluation (e.g., Ripple Effects Mapping) to elucidate factors most important to participants and other stakeholders [Limitations of our study should be considered. Because our primary outcome is measured by actigraphy, those who are not able to ambulate independently are not included in the evaluation cohort. However, we do allow those using certain assistive devices (such as walkers) to participate in the evaluation cohort, as we thought actigraphy would be appropriate in these instances. In addition, only those willing to participate are included in the evaluation cohort. These may create bias in our sampling frame. Our program is available in English and Spanish, which represents most languages spoken in public housing developments. However, while people who speak other languages will be welcome to participate in E level intervention activities, they may not feel as welcome or be able to participate fully. Finally, the study is conducted in only one city, which may limit external generalizability.In conclusion, a multilevel, multicomponent community-based study is being conducted to test whether individual- and environmental-level intervention programming promotes moderate intensity physical activity among urban public housing residents.