Adolescence is a time during which physical activity is reported to decline steeply, putting both current and future health and wellbeing at risk. The four studies included in this thesis were designed to contribute to our understanding of why participation in leisure timeexercise declines during adolescence. In particular, the studies aimed to test a proposed pathway of effects between negative body or weight related self perceptionsand engagement in volitional exercise through the application of self determination theory (SDT; Deci & Ryan, 2000). The roles of extrinsic goal content, need satisfaction and motivation on leisure timeexercise (LTE) were tested at both a crosssectionaland longitudinal level, and analysed in detail through a qualitative study. A final experimental study was then conducted to test the degree to which some of these observed constructs are open to change, and to explore whether focusing adolescents on exercising for goals of physical appearance in a single exercise session (PE) would be facilitative of involvement in PE through heightening its relevance, or inhibitive of self determinedmotivation through the pathway of effects predicted for extrinsic goals by SDT.
Weight relatedphysical self perceptions(WRPSPs)were found to compromise need satisfaction and motivation to predict poorer LTE and quality of life one year later, suggesting that the reduction of, or distraction from WRPSPswould form a useful basis for exercise interventions. Adolescents showed resilience to extrinsic goals and motives for exercise, which were found to have a positive additive effect on behaviour, motivation and perceived value of activities when present in combination with intrinsic goals and motives for exercise. These findings indicated that a hierarchy of goals exists, such that goals for individual bouts of exercise are less important in determining the outcomes an adolescent will experience, than goals for exercise overall. The findings divert somewhat from SDT to suggest that when combined with a basis of intrinsic motivation towards exercise, the introduction of a highly relevant, yet extrinsic goals may be useful in initiating (although not necessarily maintaining) effortful goal directed behaviour in adolescence.
|Date of Award||1 Apr 2007|
|Supervisor||Martyn Standage (Supervisor) & Suzanne Skevington (Supervisor)|