Leading a physically active lifestyle is well known to be associated with a range of health benefits, yet there is concern that a large proportion of children are insufficiently active. To date, intervention strategies have had little sustained impact of increasing activity, indicating that a greater understanding of physical activity behaviour is required. The objective of this thesis by published works was to examine the patterns of, and key influences on physically activity of Australian children. In order to achieve this aim, the thesis includes four first author peer reviewed publications. Data were collected as part of the Lifestyle of our Kids (LOOK) study; a collaborative, multidisciplinary longitudinal study over 8 years of children from Canberra, Australia. Participants were initially aged 8 years (N= 853),from 29 government funded primary schools. The primary outcome measure of interest was objectively measured physical activity (pedometers and accelerometers) collected over one week annually from age 8 to 12 years and again at age 16 years. This thesis also incorporates a set of secondary potential explanatory variables of activity including cardio-respiratory fitness (20m multistage run),body composition (dual emission X-ray absorptiometry) and family and subject-level survey data. Paper #1 examined the weekly physical activity patterns of the LOOK cohort. Longitudinal data revealed a distinct day-to-day habitual physical activity pattern whereby activity generally increased on school days from Monday through to Friday before declining considerably over the weekend. Underlying this pattern was the finding that the majority of children were insufficiently active compared to recommended guidelines and girls were substantially less active than boys. Paper #2 investigated gender differences in activity further by comparing a set of potential individual and contextual explanatory variables based on the socio-ecological framework. Girls’ lower activity can be explained, in part, by weaker positive influences on physical activity at school, through lower levels of parental support for their child to be active and through lower participation in extracurricular club sport. Paper #3 sought to further quantify the effect of extracurricular sports club participation on physical activity. Subjects taking part in club sports were found to be more active, fitter and to have less body fat than those not in sports clubs, although the majority of sports participants still did not meet recommended levels of physical activity. The objective of Paper #4 was to investigate, using a randomized controlled trial design, the effect of a 4-year specialist taught PE intervention on physical activity. This study showed that a specialist-taught PE program, designed to achieve broad-based educational and health objectives, can provide higher levels of activity during PE lessons than the usual practice PE conducted by generalist class-room teachers. However, there was no evidence to suggest that this translated to an increase in daily habitual physical activity. The uniqueness of this research lies in the breadth of measures taken over an 8-year period during the key period of mid to late childhood to adolescence. Collectively, findings from this thesis indicate that children in the current study require strategies to improve physical activity levels. Both extracurricular sport clubs and PE have potentially important roles to play for promoting physical activity - but in order to ensure children are sufficiently active on a daily basis, interventions also need to target opportunities outside of these times using a gender considered approach.
Physical activity : patterns and influences in Australian children
Telford, R. (Author). 2016
Student thesis: Doctoral Thesis