Thesis (M.A.)--York University, 2008. Graduate Programme in Psychology. / Typescript. Includes bibliographical references (leaves 78-95). Also available on the Internet. MODE OF ACCESS via web browser by entering the following URL: http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&res_dat=xri:pqdiss&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&rft_dat=xri:pqdiss:MR51611

Asthma is the leading chronic disease of children in industrialized countries. In Canada, it is the most common cause of hospital admissions in children. Data were assembled for all asthma hospitalizations in Canada from 1990 to 2000 by the Canadian Institute for Health Information (CIHI). The annual cycles of asthma hospitalization among Canadian children from 1990 to 2000 were compared. For every year, region and latitude, asthma hospitalizations were lowest in July and August followed by a major peak in September then a rapid decline. Contingency table analyses were done to examine the homogeneity of the distributions of asthma hospitalization counts for the factors age, gender, region and latitude groups. Age, region and latitude groups were found to be significantly different with respect to their distribution of asthma counts. However, the distributions of asthma hospitalization counts did not differ significantly for gender. A nonlinear least squares model was fitted to the asthma hospitalization data for weeks 30 to 42. The primary objective was to obtain estimates of the parameter that describes the timing of the September peak. Next, a likelihood ratio test was done to assess the homogeneity of the September peaks for the factors age, gender, latitude and region. We found that, apart from gender, the September peaks were significantly different. Furthermore, the annual cycle of asthma hospitalization for children aged 2 to 4 was identical to that of children aged 5 to 15 except the peak in hospitalization for 2 to 4 year olds occurred on average 2 days after the older children. We suspect that the increase prevalence of and exposure to viral infections, exposure of school-aged children to allergens at school and the transmission of these factors to younger siblings are responsible for the September asthma epidemic. A Quasi-Poisson log-linear model was also fitted to the data to assess jointly the effects of age, gender, latitude, year and risk group size. The data were overdispersed, after accounting for overdispersion, we found that age, gender, latitude, year and the interactions between age and gender, age and latitude and gender and latitude were significant in explaining the data. Surprisingly, time had a negative effect suggesting a tendency to decline in the number of asthma incidences requiring hospitalization over the years. / Thesis / Master of Science (MSc)

Canadian children have policy and infrastructure rich environments, but their physical activity levels are among the lowest in the world. The disconnection between opportunities to be active and actual physical activity suggests that factors other than policies and resources need to be investigated in the Canadian context. Finding ways to increase physical activity levels is critical in order for children to obtain adequate levels throughout childhood. Fundamental motor skill proficiency and positive perceptions of physical competence have been previously identified as factors that may contribute to physical activity engagement across childhood. This dissertation examined the developmental trajectories of fundamental motor skill proficiency (FMS), perceptions of physical competence (PPC), physical activity (MVPA), and sedentary behaviour (SB) from kindergarten to grade 2, in both cross-sectional and longitudinal samples of children. Three interrelated studies were conducted to address the overall purpose. The aim of study 1 was to examine the change in the relationship between fundamental motor skill proficiency and perceptions of physical competence from early to the beginning of middle childhood. The Test of Gross Motor Development–2 (TGMD- 2) and The Pictorial Scale of Perceived Competence and Social Acceptance for Young Children were used to measure FMS and PPC from kindergarten to grade 2 (n=250). Motor skills improved from kindergarten to grade 2, while PPC was high in both kindergarten and grade 2. Mixed design analyses of variance revealed overall significant effects for object control skills and PPC from kindergarten to grade 2. Furthermore, boys had higher object control skills and girls had higher locomotor skills and perceived physical competence. The aim of study 2 was to examine the levels of physical activity and sedentary behaviours sequentially from kindergarten to grade 2. A sample of 176 cross-sectional and 21 longitudinal participants wore Actigraph GT1M accelerometers for ≥ 10hrs per day for 7 days to measure physical activity and sedentary behaviour. Physical activity levels were lower in grade 2, while sedentary behaviour was higher. Pearson product- moment correlations revealed sedentary behaviour tracked more consistently over time than MVPA or total physical activity. The aim of study 3 was to examine whether perceptions of physical competence mediated the relationship between motor competence as the predictor variable and both physical activity and sedentary behaviour as dependent variables among children in grade 2 or 3. The TGMD-2 measured FMS and Actigraph GT1M accelerometers measured physical activity and sedentary behaviour for 129 grade 2–3 children. The Pictorial Scale of Perceived Competence and Social Acceptance for Young Children and The Self- Perception Profile for Children were used to assess PPC. Overall, PPC did not mediate the relationship between object control skills and MVPA or SB. Also, the path between object control skills and MVPA was significant for boys as were the paths between MVPA and SB for boys and girls. / Graduate