Physical and Social Environmental Influence on Children's Exercise: Preparation (Pre-PLACE)

Low levels of physical activity in childhood are related to obesity and risk for diabetes and cardiovascular disease. This translational study is an attempt to take interventions that have been shown to be effective in highly controlled setting and implement them in the community. We will utilize a form of a single case design (i.e., stepped-wedge or multiple-baseline design), which is an underused, though promising, alternative to the traditional, parallel-group randomized trial in which each study participant acts as his/her own control. Participants will be randomized to baseline periods of varying length such that the change in the study outcome can be causally attributed to introduction of the intervention. In accordance, families will be randomized to a 2, 4, or 6-week baseline period before being administered the P-Mobile app based intervention. All families will receive the same P-Mobile intervention following the baseline period. The P-Mobile intervention will be delivered to parents via the P-Mobile smartphone app; it consists of 10 lessons designed to increase physical activity in children. The parents will also receive notifications designed to prompt physical activity, motivate, and remind parents of lesson content. The intervention will also utilize an adaptive step goal approach, in which the step goal is modified based on each participant's individual performance. The primary aims of the study are: (1) To estimate several parameters, which will allow us to redesign our study as a single case design (and to conduct simulation-based power calculations): (a) average day-to-day variability in daily steps during the baseline period, (b) average autocorrelation in the daily step data, and (c) average effect size at 2 weeks, 4 weeks, and 6 weeks after introduction of the intervention. (2) To test the feasibility of the P-Mobile app (3) To demonstrate our ability to recruit participants from targeted neighborhoods.