Crystal Smit

Chapter 5 98 H 2 O intervention, we addressed three specific research aims. The first aim was to evaluate the influence agents’ general experiences with the training by assessing their ratings of their enjoyment of the training, the duration, and perceived autonomy support during the training. The second aim was to assess whether the training motivated the influence agents to drink more water themselves by examining changes in the influence agents’ intrinsic motivation and water consumption before and after the start of the intervention. The third aim was to examine whether the influence agents were successful in motivating their peers by investigating changes in the peers’ intrinsic motivation, perceived social support, and perceived social norms before and after the start of the intervention. METHODS Design This study was integrated into the Share H 2 O intervention effectiveness study (Smit et al., 2020), which was part of the second data collection phase of the MyMovez research program (see Bevelander et al., 2018) for a detailed description of the MyMovez program). The study reported on data collected from both the selected influence agents and their peers. The required sample size for the Share H 2 O effectiveness studywas basedon the previous pilot study (Smit et al., 2016), inwhich a small effect on water and SSB consumption was found with 210 children in the intervention and control condition. To calculate the sample for the effectiveness study (Smit et al., 2020), this number was multiplied by 1.5 to add the third group (i.e., the active control), resulting in a minimum number of 315 children across the three groups. Ethical approval was obtained from the Ethics Committee of the Faculty of Social Sciences at Radboud University (ECSW2014–100614-222) and the ethical review board from the European Research Council (617253). The design of the Share H 2 O social network intervention was preregistered at the Netherlands Trial Register (NL6905).