Jens Bucksch is a post-doc research associate at School of Public Health, Department of Prevention and Health Promotion, Bielefeld University. He gained his PhD for his work on the transtheoretical model for behavior change among adolescents' physical activity behaviour. Jens Bucksch has been actively involved in teaching and research in different university departments of various disciplines (i.e. Public Health, Sports Sciences, Epidemiology), treating themes such as adolescent health, physical activity and health, models and theories of behaviour change, principles of physical activity and health promotion in communities. From 2011 to 2014 he was managing director of the WHO Collaborating Centre for Child and Adolescent Health Promotion at the Bielefeld University. In 2011 Jens joined the German HBSC network. Since 2012 he is one of the co-chairs of the Physical Activity Focus Group within the international HBSC network. His scientific activity emphasis is on physical activity and sedentary behaviour within a behavioural epidemiology framework.