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.