Table 1.

Overview of measures

Measurement methodology	Outcome
Medical testing	Body weight and height (BMI percentiles)
	Body composition (fat mass)
	Waist circumference [35]
	Blood pressure
	Resting heart rate
	Heart rate after stress
	Recovery heart rate
Physical testing	Cardiovascular fitness [36]
Questionnaire	Socio-demographic characteristics
	Age
	Gender
	Migration background
	Socio-economic status [37]
	Lifestyle Behavior
	Physical activity* [38-40]
	Sedentary behavior [40]
	Use of tobacco [41]
	Use of alcohol [42,43]
	Food pattern [44]
	Psychological constructs
	General self-efficacy [45]
	Self-efficacy towards physical exercise [46]
	Self-concept for general physical capacity and physical attractiveness [47,48]
	Enjoyment of physical activity [49]
	Enjoyment of sedentary behavior [49]
	Sensation seeking [50]
	Physical well-being [51]
	Psychological well-being [51]
	Depression [52]
	Intention for physical activity [53]
	Social factors
	Parental support for physical activity [25]
	Friends physical activity*
	Normative expectations*
	Environmental situation to be physical active*
Qualitative methods	Activating-strategies (group discussion, document analysis)
	Interactive processes (group discussion)

*self-constructed items.