Crystal Smit

Evaluation of the Motivation Process 5 99 Procedure Both suburban and urban schools throughout the Netherlands were invited to participate via an email to the school principal. Only primary or secondary schools following a regular education program and with classes between the 4th and 7th grade (i.e., students aged 9 to 13 years) were invited to participate in the MyMovez research program. The project focused on this age group because it is important that children learn healthy intake behaviors at an early age since the increase in overweight and obesity is the steepest around the ages of 16 to 20 years (CBS, 2020b) and intake habits and preferences developed in childhood can persist into adulthood (Lake, Mathers, Rugg-Gunn, & Adamson, 2006). After obtaining written permission from the school principals, an information letter was distributed to the children and their parents. In addition, pitches were delivered in school classes to recruit participants. Given the age of the participants ( < 16 years), written informed consent was obtained from a parent or legal guardian as well as the children themselves. Subsequently, the participating schools were randomly assigned to one of the five conditions of the MyMovez program (see Smit et al., 2020; van Woudenberg et al., 2020 for a detailed description of the conditions). The current study sample included the five (sub) urban primary schools (i.e., eight classes from grades 4–6) assigned to the condition exposed to the Share H 2 O social network intervention. For the overall Share H 2 O social network intervention, data were collected at baseline (T1; February–March 2018) immediately after the start of the intervention (T2; April–May 2018), and during a follow-up 4 weeks later (T3; June–July 2018). The evaluation measurements of the current study were collected at T1 and T2 only. At each assessment, children received a smartphone with a preinstalled research application and a wrist-worn accelerometer for seven days (Bevelander et al., 2018; MyMovez, 2017). Via the research application, children received daily questionnaires and were able to use a social media platform (Social Buzz) , create a personalized avatar, and play a puzzle game. In the Social Buzz , children could chat, share pictures, and short videos with their peers through the social media platform integrated in the research application.