School gate to dinner plate : sedentary and physically active behaviours in adolescents after school

• Main Author: Atkin, Andrew J.
• Published: Loughborough University 2009
• Subjects: 370.15
• Online Access: http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.539447

Against a backdrop of rising overweight and obesity, there is a need to further our understanding of physical activity and sedentary behaviour patterns in young people to aid the development of behaviour change strategies that may bring about an increase in energy expenditure. Sedentary and active behaviours exhibit temporal patterning, thus it may be beneficial to examine behaviour and associations between behaviours during specific periods of the day This thesis presents five studies that examine sedentary and physically active behaviours in adolescents during the three hours immediately after school. Chapter 2, using data from a large study of adolescents in the UK, describes physical activity and sedentary behaviour patterns between 15.30h - 18.30h, and examines the contribution of this period relative to broader leisure-time behaviour patterns. In chapter 3.1, the' associations between a broad range of sedentary behaviours and objectively assessed physical activity are examined during the after school hours, providing unique insight into the interactions between behaviours at this time. Chapter 3.2 explores the social and environmental context of selected sedentary and active behaviours after school, enabling a more complete understanding of where and with whom young people spend their time during these hours. Chapter 4 is a systematic literature review of interventions to increase physical activity in young people conducted in the hours immediately after school. Together, the four studies described above established a rationale and informed the content of a pilot family-based intervention to reduce screen-time and increase physical activity after school, presented in Chapter 5. Approximately 40% of adolescents' leisure-time physical activity occurs in the three hours immediately after school, suggesting that this is a critical period in which young people obtain a significant proportion of their daily leisure-time activity. However, sedentary behaviours, particularly screen-based media, account for the majority of time-use during these hours, and may displace participation in physical activity. The development of time-targeted intervention strategies, with a focus upon the after school period, holds considerable promise for the promotion of physical activity in young people.