Pre-trial phase/healthcare practitioner:  Inclusion criteria:  - being a healthcare practitioner or manager involved in the treatment of children with obesity at a paediatric healthcare clinic in Region Västra Götaland  Clinical trial/patients:  Inclusion criteria:  aged 6-12 years diagnosed with obesity (age adjusted BMI>ISO-BMI 30) having an insufficient physical activity level according to national recommendations being willing to participate and perform the chosen activity/-ies having a parent who is willing to participate.  Exclusion criteria:  severe psychiatric comorbidity severe intellectual or physical disability