Parents play a critical role in influencing their young children's physical activity (PA) and sedentary time (ST). Despite this, many young children (aged 3-4y) and their parents are insufficiently ac Show more
Parents play a critical role in influencing their young children's physical activity (PA) and sedentary time (ST). Despite this, many young children (aged 3-4y) and their parents are insufficiently active and engage in high amounts of ST. M-health interventions targeting PA and ST have seldom been tested in this population. The objective of this study was to examine the effectiveness and acceptability of the Active Family m-health intervention on the PA and ST of young children and their parents. Twenty-five stay-at-home parent-child dyads from Canada took part in the 2-week just-in-time micro-randomized controlled trial. Parents received seven text message prompts per day, where they were randomized to receive either a micro-intervention (activity suggestion) or control (no suggestion). Parents and children wore ActiGraph accelerometers to measure ST, light [LPA], and moderate-to-vigorous physical activity [MVPA]. Parents also completed a short online acceptability survey. A centred and weighted least square regression was used to analyze the effect of activity suggestions on the 60-min ST, LPA, and MVPA of parents and children following suggestion randomization. Descriptive statistics and content analysis were used to analyze acceptability survey responses. Micro-interventions were not effective at changing children's or parent's proximal ST (d = 0.01, p = .878; d = -0.09, p = .485, respectively), LPA (d = 0.03, p = .714; d = 0.03, p = .729, respectively), or MVPA (d = -0.05, p = .511; d = 0.10, p = .480, respectively). Interventions became more effective at increasing MVPA over time for parents (b = 0.47, 95%CI = 0.12, 0.83, p = .013). Among children, intervention effectiveness varied by contextual factors (e.g., weather). The intervention was largely acceptable, appropriate, and feasible for parents, though they did offer suggestions for improvement. Overall, micro-interventions did not significantly change parents or young children's proximal movement. Though, this approach showed promise for increasing parent's MVPA over time and for supporting children's activity under specific conditions. Show less