Table 1.

Description of the assessed variables at baseline by type of secondary school

	Total	Highest secondary school	Lower secondary schools	Possible range
	(n = 850)	(n = 574)	(n = 276)
	M (SD)	M (SD)	M (SD)
Consumption of screen-based media (hours/day)
TV/video	1.66 (1.29)	1.27 (1.13)	2.08 (1.49)	0-5
Game console	0.71 (1.14)	0.54 (.91)	1.05 (1.46)	0-5
PC/internet	1.50 (1.41)	1.44 (1.34)	1.64 (1.54)	0-5
Mobile phone	1.42 (1.65)	1.33 (1.60)	1.61 (1.75)	0-5
Total screen time	5.31 (3.66)	4.79 (3.29)	6.38 (4.15)	0-20
Physical activity (training sessions/week)
PA organized	1.76 (1.73)	1.91 (1.74)	1.43 (1.67)	0-6
PA non-organized	2.17 (2.02)	2.18 (1.99)	2.15 (2.08)	0-6
Total physical activity	3.93 (2.83)	4.10 (2.81)	3.58 (2.88)	0-12
School grades
Mathematics	2.64 (0.85)	2.53 (0.85)	2.89 (0.80)	1-4
German	2.34 (0.76)	2.20 (0.74)	2.61 (0.72)	1-4
Physical Education	2.16 (0.86)	1.98 (0.78)	2.53 (0.90)	1-4

Better school achievement is represented by lower school grades (following the German grading system). PA physical activity