Pupils' and teachers' experiences with implementing standing desks in secondary schools in Belgium.

Objective: Sedentary behaviour is associated with adverse health outcomes in adolescents, yet adolescents spend most of their day sedentary, particularly at school. Standing desks have been proposed to reduce sitting time, but implementation challenges remain. This pilot study evaluated the process of implementing standing desks in secondary schools. Methods: A mixed-methods study was conducted from September to December 2020 in Flanders, Belgium, in three schools, each including one 7th- or 8th-grade class. Ten standing desks were used for 4-5 weeks in each class. Implementation was assessed retrospectively using pupil focus groups, teacher interviews, and pupil questionnaires. Qualitative data were analysed using reflexive thematic analysis. Questionnaire data were analysed using descriptive statistics. Results: A convenience sample of 58 out of 68 pupils (mean age 13.0 ± 0.7 years, 44.8 % boys) completed the questionnaire. Pupils reported using the standing desks on average 8.9 ± 5.4 h/week, with qualitative data revealing a decline in use over time. Furthermore, experiences of using standing desks among pupils and teachers varied: some reported better concentration among pupils, while others mentioned discomfort, fatigue, and distractions. Conclusions: Implementing standing desks resulted in mixed experiences among pupils and teachers. Future interventions should encourage gradual increases in standing time and frequent posture changes. Trial registration: This study has been registered at ClinicalTrials.gov in January 2020 (NCT04327414; released on March 11, 2020).