Thesis--PlanB (M.S.)--University of Wisconsin--Stout, 2003. / ACCOMPANYING MATERIAL (1/2 IN. VIDEOCASSETTE) IS HOUSED IN THE ARC. Includes bibliographical references.

Thesis (M. Sc.)--University of Hong Kong, 2001. / Includes bibliographical references (leaves 89-100).

Thesis (M. Psych. Sport. & Ex.)--University of Queensland, 2002. / Includes bibliographical references.

Thesis (M.Med.Sc.)--University of Hong Kong, 2009. / Includes bibliographical references (p. 49-53).

The continued surge in childhood obesity rates globally has created much impetus for researchers to develop intervention strategies effective in changing physical activity behavior during childhood. Despite such interest there has been limited success, and very rarely have cross-cultural applicability of these initiatives been considered. This thesis begins with an examination of the applicability of a Western-modeled school-based intervention, America on the Move, using pedometers and point-of-choice prompts in an attempt to change the walking behavior of Chinese Hong Kong children (Chapter 2). To achieve this, the intervention mapping protocol was followed. The process comprised three studies. First, health messages prompting walking behaviors were developed and tested for motivational properties. Second, two piezoelectric pedometers were validated for our target population, and finally, a 7-week pilot of the intervention using the validated health messages and pedometers was implemented and evaluated among 8-12 year old Chinese Hong Kong children. The second part of the thesis took the unexpected results of the pilot intervention and explored how a goal-related psychological construct, emotional rehearsal, which has been associated with dysregulated health behaviors, may contribute to these. This part commences with an overview of the conceptualization of rehearsal and presentation of a conceptual model between stress and dysregulated health behavior mediated by the propensity for rehearsal (Chapter 3). Three studies were then undertaken to examine the relationship between rehearsal and dysregulated physical activity behavior. First, a Chinese version of the Rehearsal Scale for children (RSC-C) measuring propensity of rehearsal in children was adapted and validated for use in the subsequent two studies (Chapter 4). The second study investigated the existence of pedometer reactivity and how this might interact with propensity for rehearsal (Chapter 5). Lastly, the relationship between rehearsal and child health was examined through an assessment of the propensity for rehearsal and central adiposity status. Taken together, results of these empirical studies show promise in supporting the proposition that the effectiveness of intervention strategies may be culturally bound via the propensity for rehearsal and its link with cardiovascular health. Limitations of this thesis and future research directions are explored in the final chapter. / published_or_final_version / Human Performance / Doctoral / Doctor of Philosophy

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Nitric Oxide (NO) has been detected in the expiratory air of normal animals and human subjects. Recent experiments revealed that expiratory NO production rises during exercise and correlates well with O$ sb2$ consumption and heart rate. Whether or not physical conditioning influences expiratory NO output production remains unclear. In this study, NO concentration in expired gas was measured in 18 healthy male volunteers subdivided into 3 groups (sedentary, intermediate, athletes) based on their state of physical conditioning. Measurements were taken at rest and during two steady-state exercise bouts on a bicycle ergometer designed to elicit VO$ sb2$ of 1 and 2 1/min with the athletes performing an additional bout at VO$ sb2$ of 4 1/min. In the sedentary and intermediate groups, expired NO concentrations declined significantly with increasing VO$ sb2.$ In contrast, expired NO levels declined only slightly with increasing VO$ sb2$ in athletes. At a VO$ sb2$ of 2 1/min, expired NO concentrations were significantly higher in athletes compared with the other groups. When correlated with V$ rm sb{E},$ expired NO concentrations declined linearly with the increase in $ rm V sb{E}$ in sedentary and intermediate groups but not in the athletes. Only the athletes had a significant linear increase in NO output (expired NO x V$ rm sb{E})$ with increasing VO$ sb2$ (p $<$ 0.001). These results support the notion that physical conditioning increases expiratory NO output during exercise. We speculate that the rise in expiratory NO output in athletes might be due to increased vascular and/or epithelial production of NO. Enhanced vascular NO production may be the result of increased shear stress and/or upregulation of endothelial NO synthase gene expression.

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