Effects of physical activity planning interventions on reducing sedentary behavior in parent-child dyads: A randomized controlled trial.

Effects of parent-child dyad interventions on behavior remain unclear. This randomized controlled trial investigated if, compared with a control condition, three types of physical activity (PA) planning interventions (individual "I-for-me," dyadic "we-for-me," and collaborative "we-for-us") would reduce sedentary behavior (SB) time in parents and their children. The study involved 247 dyads comprising parents (aged 29-66) and their children (aged 9-15), randomized into one of the three types of PA planning-intervention arms or the control condition. Mixed models were applied to analyze data from a preregistered trial (NCT02713438) with the outcome of accelerometer-measured SB time, assessed at 1-week and 36-week follow-ups. Although children's SB remained unaffected by the planning interventions, a small reduction of SB time was found among parents in the collaborative (p = .048) and individual (p = .042) planning conditions. The effects were observed at the 1-week follow-up only. While short-term reductions in parents' SB were achieved, these were not sustained long-term. PA planning interventions delivered to parent-child dyads did not substantially reduce children's SB, which may be due to young people's needs of increased independence from their parents.