1.Hallal, PC, Victora, CG, Azevedo, MR et al. (2006) Adolescent physical activity and health: a systematic review. Sports Med 36, 1019–1030.
2.Summerbell, CD, Waters, E, Edmunds, LD et al. (2005) Interventions for preventing obesity in children. Cochrane Database Syst Rev 20, issue 3, CD001871.
4.US Department of Health and Human Services (1996) Physical Activity and Health: A Report of the Surgeon General. Atlanta, GA: US Department of Health and Human Services, Centers for Disease Control and Prevention.
5.Currie, C, Gabhainn, S, Godeau, E et al. (editors) (2008) Inequalities in Young People’s Health: HBSC International Report from the 2005/2006 Survey. Copenhagen: WHO Regional Office for Europe.
6.Nilsson, A, Anderssen, SA, Andersen, LB et al. (2009) Between- and within-day variability in physical activity and inactivity in 9- and 15-year-old European children. Scand J Med Sci Sports 19, 10–18.
7.Corder, K, Ekelund, U, Steele, RM et al. (2008) Assessment of physical activity in youth. J Appl Physiol 105, 977–987.
8.Kristensen, PL, Korsholm, L, Moller, NC et al. (2008) Sources of variation in habitual physical activity of children and adolescents: the European Youth Heart Study. Scand J Med Sci Sports 18, 298–308.
9.Dunton, G, Whalen, C, Jamner, L et al. (2007) Mapping the social and physical contexts of physical activity across adolescence using ecological momentary assessment. Ann Behav Med 34, 144–153.
10.Levin, S, Lowry, R, Brown, DR et al. (2003) Physical activity and body mass index among US adolescents: Youth Risk Behavior Survey, 1999. Arch Pediatr Adolesc Med 157, 816–820.
11.Olds, T, Wake, M, Patton, G et al. (2009) How do school-day activity patterns differ with age and gender across adolescence? J Adolesc Health 44, 64–72.
12.Janssen, I, Katzmarzyk, P, Boyce, W et al. (2005) Comparison of overweight and obesity prevalence in school-aged youth from 34 countries and their relationships with physical activity and dietary patterns. Obes Rev 6, 123–132.
13.Moreno, LA, De Henauw, S, González-Gross, M et al. (2008) Design and implementation of the Healthy Lifestyle in Europe by Nutrition in Adolescence Cross-Sectional Study. Int J Obes (Lond) 32, Suppl. 5, S4–S11.
14.De Henauw, S, Gottrand, F, De Bourdeaudhuij, I et al. on behalf of the HELENA Study Group (2007) Nutritional status and lifestyles of adolescents in a public health perspective. The HELENA Project – Healthy Lifestyle in Europe by Nutrition in Adolescence. J Public Health 15, 187–197.
15.Moreno, LA, González-Gross, M, Kersting, M et al. on behalf of the HELENA Study Group (2008) Assessing, understanding and modifying nutritional status, eating habits and physical activity in European adolescents: The HELENA (Healthy Lifestyle in Europe by Nutrition in Adolescence) Study. Public Health Nutr 11, 288–299.
16.Craig, C, Marshall, AL, Sjöström, M et al. (2003) International Physical Activity Questionnaire: 12-country reliability and validity. Med Sci Sports Exerc 35, 1381–1395.
17.Hagströmer, M, Bergman, P, De Bourdeaudhuij, I et al. on behalf of the HELENA Study Group (2008) Concurrent validity of a modified version of the International Physical Activity Questionnaire (IPAQ-A) in European adolescents – The HELENA study. Int J Obes (Lond) 32, Suppl. 5, S42–S48.
18.Haerens, L, Deforche, B, Maes, L et al. (2007) Physical activity and endurance in normal weight versus overweight boys and girls. J Sports Med Phys Fitness 47, 344–350.
19.Nagy, E, Vicente-Rodriguez, G, Manios, Y et al. on behalf of the HELENA Study Group (2008) Harmonization process and reliability assessment of anthropometric measurements in a multicenter epidemiologic study in adolescents. Int J Obes (Lond) 32, Suppl. 5, S58–S65.
20.Cole, TJ, Bellizzi, MC, Flegal, KM et al. (2000) Establishing a standard definition for child overweight and obesity worldwide: international survey. BMJ 320, 1240–1243.
21.Cole, TJ, Flegal, KM, Nicholls, D et al. (2007) Body mass index cut offs to define thinness in children and adolescents: international survey. BMJ 335, 194.
22.Von Rueden, U, Gosch, A, Rajmil, L et al. , the European KIDSCREEN Group (2006) Socioeconomic determinants of health related quality of life in childhood and adolescence: results from a European study. J Epidemiol Community Health 60, 130–135.
23.Currie, C, Molcho, M, Boyce, W et al. (2008) Researching health inequalities in adolescents: the development of the Health Behaviour in School-Aged Children (HBSC) Family Affluence Scale. Soc Sci Med 66, 1429–1436.
24.Napolitano, M, Fotheringham, M, Tate, D et al. (2003) Evaluation of an internet-based physical activity intervention: a preliminary investigation. Ann Behav Med 25, 92–99.
25.Rzewnicki, R, Auweele, Y & De Bourdeaudhuij, I (2002) Addressing overreporting on the International Physical Activity Questionnaire (IPAQ) telephone survey with a population sample. Public Health Nutr 6, 299–305.
26.Rütten, A, Ziemainz, H, Schena, F et al. (2003) Using different physical activity measurements in eight European countries. Results of the European Physical Activity Surveillance System (EUPASS) time series survey. Public Health Nutr 6, 371–376.
27.Armstrong, N & Welsman, JR (2006) The physical activity patterns of European youth with reference to methods of assessment. Sports Med 36, 1067–1086.
28.Tammelin, T, Ekelund, U, Remes, J et al. (2007) Physical activity and sedentary behaviors among Finnish youth. Med Sci Sports Exerc 39, 1067–1074.
29.Trost, S, Pate, R, Sallis, J et al. (2002) Age and gender differences in objectively measured physical activity in youth. Med Sci Sports Exerc 34, 350–355.
30.Metcalf, B, Voss, L, Hosking, J et al. (2008) Physical activity at the government recommended level and obesity-related health outcomes: a longitudinal study (Early Bird 37). Arch Dis Child 93, 772–777.
31.Pate, R, Freedson, P, Sallis, J et al. (2002) Compliance with physical activity guidelines: prevalence in a population of children and youth. Ann Epidemiol 12, 303–308.
32.Pahkala, K, Heinonen, OJ, Lagström, H et al. (2007) Leisure-time physical activity of 13 year-old adolescents. Scand J Med Sci Sports 17, 324–330.
33.Sayer, L (2005) Gender, time and inequality: trends in women’s and men’s paid work, unpaid work and free time. Soc Forces 84, 285–301.
34.Nelson, M, Neumark-Stzainer, D, Hannan, PJ et al. (2006) Longitudinal and secular trends in physical activity and sedentary behaviour during adolescence. Pediatrics 118, 1627–1634.
35.Steinbeck, K (2001) The importance of physical activity in the prevention of overweight and obesity in childhood: a review and an opinion. Obes Rev 2, 117–130.
36.Ekelund, U, Poortvliet, E, Nilsson, A et al. (2001) Physical activity in relation to aerobic fitness and body fat in 14- to 15-year-old boys and girls. Eur J Appl Physiol 85, 195–201.
37.Katzmarzyk, PT, Malina, RM, Song, TM et al. (1998) Physical activity and health-related fitness in youth: a multivariate analysis. Med Sci Sports Exerc 30, 709–714.
38.Hanson, M & Chen, E (2007) Socioeconomic status and health behaviors in adolescence: a review of the literature. J Behav Med 30, 263–285.
39.Shi, Z, Lien, N, Kumar, B et al. (2006) Physical activity and associated socio-demographic factors among school adolescents in Jiangsu Province, China. Prev Med 43, 218–221.
40.Giles-Corti, B & Donovan, R (2002) Socioeconomic status differences in recreational physical activity levels and real and perceived access to a supportive physical environment. Prev Med 35, 601–611.
41.McMurray, R, Ring, K, Treuth, M et al. (2004) Comparison of two approaches to structured physical activity surveys for adolescents. Med Sci Sports Exerc 36, 2135–2143.
42.Wong, S, Leatherdale, S & Manske, S (2006) Reliability and validity of a school-based physical activity questionnaire. Med Sci Sports Exerc 38, 1593–1600.