Cheung, Pui-yee. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2002. / Includes bibliographical references (leaves 77-83). / Text in English; abstracts in English and Chinese. / Cheung, Pui-yee. / Acknowledgements --- p.i / Abstract --- p.ii / Table of Contents --- p.iv / List of Tables --- p.vii / List of Figures --- p.viii / Chapter CHAPTER ONE --- INTRODUCTION / Chapter 1.1 --- Background --- p.1 / Chapter 1.1.1 --- Fitness Testing in children --- p.2 / Chapter 1.1.2 --- Constraints in the direct VO2 peak measurement on children --- p.3 / Chapter 1.1.3 --- The application of field test in assessing children aerobic fitness --- p.4 / Chapter 1.2 --- Purpose of the Study --- p.7 / Chapter 1.3 --- Operational Definitions --- p.7 / Chapter 1.4 --- Delimitations --- p.9 / Chapter 1.5 --- Limitations --- p.10 / Chapter 1.6 --- Hypotheses --- p.10 / Chapter 1.7 --- Significance of the Study --- p.11 / Chapter CHAPTER TWO --- LITERATURE REVIEW / Chapter 2.1 --- Needs of assessment on children aerobic fitness --- p.13 / Chapter 2.2 --- Common field tests to measure children's aerobic fitness --- p.15 / Chapter 2.2.1 --- Run Test --- p.15 / Chapter 2.2.2 --- Walk Test --- p.17 / Chapter 2.2.3 --- Step Test --- p.18 / Chapter 2.2.4 --- Comparison of field tests --- p.20 / Chapter 2.3 --- Different step test protocols --- p.21 / Chapter 2.3.1 --- Astrand-Rhyming Step Test --- p.23 / Chapter 2.3.2 --- Harvard Step Test --- p.24 / Chapter 2.3.3 --- The Katch Pulse Recovery Step Test --- p.26 / Chapter 2.3.4 --- Hodgkins and Skubin Step Test --- p.27 / Chapter 2.3.5 --- Queen College Step Test --- p.28 / Chapter 2.3.6 --- Height-Adjusted Step Test --- p.30 / Chapter 2.3.7 --- The Canadian Home Fitness Step Test --- p.31 / Chapter 2.4 --- Related issues in evaluating aerobic fitness by step test --- p.35 / Chapter 2.4.1 --- Heart rate measurement --- p.35 / The accuracy of HR measurement --- p.37 / Chapter 2.4.2 --- Leg Length --- p.38 / Chapter 2.4.3 --- Platform Height --- p.40 / Chapter 2.4.4 --- Body Mass --- p.42 / Chapter 2.4.5 --- Stepping Frequency --- p.44 / Chapter 2.5 --- Summary --- p.46 / Chapter CHAPTER THREE --- METHODOLOGY / Chapter 3.1 --- Participants --- p.48 / Chapter 3.2 --- Procedures and Equipment --- p.49 / Chapter 3.2.1 --- Anthropometric measurement --- p.49 / Chapter 3.2.2 --- 3-minute Step Test --- p.50 / Chapter 3.2.3 --- Graded Exercise Treadmill Test --- p.52 / Graded Exercise Test Protocol --- p.53 / Determination of peak oxygen uptake (VO2 peak) --- p.53 / Chapter 3.3 --- Statistical analysis --- p.54 / Chapter CHAPTER FOUR --- RESULT / Chapter 4.1 --- Physical Characteristics of Participants --- p.56 / Chapter 4.2 --- Physiological Responses of Participants from the Step Tests --- p.57 / Chapter 4.3 --- Influence of the Order in the Participation of the Step Tests --- p.58 / Chapter 4.4 --- VO2 Peak Measurement --- p.59 / Chapter 4.5 --- HR Responses for Step Tests --- p.59 / Chapter 4.6 --- VO2 Consumption during Step Tests --- p.62 / Chapter 4.7 --- Regression Analysis for Different Stepping Frequencies of Step Tests --- p.64 / Chapter 4.8 --- Accuracy of Regression Models --- p.66 / Chapter 4.9 --- Summary of the Results --- p.69 / Chapter CHAPTER FIVE --- DISCUSSION / Validity --- p.70 / Stepping Frequency --- p.72 / HR measurement in Step Tests --- p.74 / Recommendation for future studies --- p.76 / Reference --- p.77 / Appendix A --- p.84 / Appendix B --- p.85 / Appendix C --- p.86 / Appendix D --- p.87 / Appendix E --- p.88 / Appendix F --- p.89

published_or_final_version / Public Administration / Master / Master of Public Administration

Abstract Dawn Arlotta (The Effects of HealthMPowers on the Levels of Physical Activity among Students in 13 Georgia Public Schools) (Under the direction of Dr. Marshall Kreuter and Dr. Derek Shendell) Objectives. This study evaluated a school based health and physical education program conducted in nine elementary and four middle schools in seven Metro-Atlanta school districts in Georgia. HealthMPowers served 5,644 students last year and approximately 15,000 students over the 3 year intervention. Methods. Quantitative programmatic data were collected by HealthMPowers before the intervention started (pre, 2004) and again three years later (post, 2007). HealthMPowers worked with these schools for the entire three year period and collected post Program Design and post-intervention fitness data in spring 2007. Results. The nine participating elementary schools each demonstrated an increase in student fitness levels for the fourth and fifth grades. The four middle schools demonstrated an increase in student fitness levels in at least one grade, which varied by school. Conclusion. Our findings suggested school programs can be effective in increasing physical activity and fitness scores and supports broader implementation of known successful programs. INDEX WORDS: Physical Activity, Youth, School Health Index, Coordinated School Health Program, Obesity, FITNESSGRAM, Physical Fitness Testing, Physical Education.

This study investigated the psychobiological and pacing characteristics of the 1.5 mile run. Sixty-six males (18-27 years) performed the run, and were monitored for ratings of perceived exertion, heart rate and split times. The perceived exertion values increased in a near-linear fashion inconsistent with other measures, and thus are not considered a supportable indicator of physiological performance during the run. Pace was characterized by an initial sprint that slowed to a near-steady pace and concluded with a final sprint. The initial and final sprints were most highly related to the variance of performance time. Initially, heart rate accelerated greatly. This acceleration slowed, ending in near-maximum heart rates. The data suggested that performance may rely heavily upon anaerobic mechanisms, and that variance in previously reported correlational analyses of VO2max and 1.5 mile run performance times may be somewhat due to anaerobic mechanisms.

The problem of this study is that of comparing certain physical fitness and anthropometric measures for early adolescent Mexican-American and Anglo-American males. The purposes of the study are to determine if Mexican-American and Anglo-American males differ in physical fitness or anthropometric measures; to determine if the relationships between age and physical fitness, age and arthropometric measures, and anthropometric measures and physical fitness items are significantly different for Mexican-American and Anglo-American males; to compare the rate of maturation for pre-adolescent Mexican-American and Anglo-American males in physical fitness items and anthropometric measures.

Firefighting is a very hazardous profession. Firefighters experience an injury rate that is three times higher than other physically demanding professions and the death rate in the fire service is also much higher compared to typical. Throughout the literature, data suggest the physical nature of firefighting contributes to the high incidence of injury and death among firefighters. As such, special interest groups and firefighting organizations advocate for firefighters to exercise and stay fit in order to safeguard their physical health. Yet, despite these efforts, firefighters still experience a very high incidence of back injuries and heart attacks which can lead to early retirement from disability or death. In the first aim of this dissertation, we examined the relationships between specific back fitness tests and history of back injuries in 113 firefighters in an effort to understand which fitness tests may aid in screening firefighters for risk of back injury. We found that a test of lumbar extension flexibility was associated with a higher incidence of back injuries among our sample (p<0.01). In the second aim of the study, we investigated whether perceived fitness was related to history of back injuries since firefighters’ perceptions of their fitness level may direct how they choose to perform job tasks that pose high risk for injury. Within the same sample of firefighters, we found that perceived fitness was not related to history of back injuries nor was the relationship between actual fitness and history of back injuries mediated by perceived fitness. However, perceived fitness correlated with scores on our back strength (r=0.28; p=0.003) and hamstring strength (r=0.21; p=0.03) tests. In the third aim of the dissertation, we sought to develop a treadmill walking protocol to screen firefighters for low aerobic capacity which is a major risk factor for heart attack. Thirty-eight male firefighters wore a vest weighing 20% of their body weight and performed a walking VO2max test in which the treadmill grade increased by 1% each minute. The predicted VO2max from this walking test was very accurate; within a standard error of the estimate of 3.2 ml/kg/min. This new (Moore) protocol requires only a standard treadmill and is more job specific than a running test. In conclusion, more research needs to be conducted to understand how firefighters’ perceived fitness directs their behaviors when performing job tasks and how high levels of fitness can protect against back injuries and heart attacks in firefighters. This dissertation has contributed to the development of screening protocols to aid in preventing these adverse events. / Graduation date: 2013

Made available in DSpace on 2015-03-26T13:22:04Z (GMT). No. of bitstreams: 1 text completo.pdf: 757671 bytes, checksum: 435de7db4aaa7b1bdaf1bc5260f57dd9 (MD5) Previous issue date: 2014-03-11 / O objetivo do presente estudo foi investigar os efeitos do treinamento físico sobre as propriedades morfológicas e mecânicas de cardiomiócitos de camundongos knockout (KO) para receptores os β1- e β2 adrenérgicos. Camundongos C57BL/6J, KO para os receptores β1-adrenérgicos, FVB/N e KO para os receptores β2-adrenérgicos com 4 meses de idade, foram inicialmente separados aleatoriamente em 8 grupos: C57c, C57t, KO β1c, KO β1t, FVBc, FVBt, KO β2c e KO β2t. Os animais dos grupos treinados (C57t, KO β1t, FVBt, KO β2t) foram submetidos a um protocolo de treinamento aeróbico de 8 semanas, 5 dias por semana, 1hora por dia, com intensidade de 60% da velocidade máxima de corrida. 3 a 4 animais de cada grupo foram separados para a análise de contração celular com perfusão do agonista β-adrenérgico isoproterenol (ISO) [100nM]. Após a eutanásia, os cardiomiócitos do ventrículo esquerdo foram isolados por dispersão enzimática. O comprimento e a largura dos cardiomiócitos foram medidos utilizando um sistema de captação de imagens e o volume celular foi calculado. As contrações celulares foram medidas através da técnica de alteração do comprimento dos cardiomiócitos, após estimulação elétrica a 1 Hz, em temperatura controlada à 37oC, usando-se um sistema de detecção de bordas. Os resultados mostraram que os camundongos KO β1 apresentaram menor comprimento celular comparados aos C57. O grupo KO β2t apresentou maior comprimento celular comparado ao grupo KO β2c. O protocolo de treinamento aumentou a amplitude de contração, a velocidade máxima de contração e a velocidade máxima de relaxamento dos cardiomiócitos dos animais KO β1t e KO β2t. O ISO não alterou a amplitude de contração, a velocidade máxima de contração e de relaxamento nos cardiomiócitos dos camundongos KO β1+ISO, já os animais KO β2+ISO apresentaram aumento nas mesmas propriedades mecânicas. Conclui-se que o protocolo de treinamento aeróbico: a) aumentou as propriedades mecânicas dos cardiomiócitos dos animais KO β1 e KO β2; b) aumentou o comprimento dos cardiomiócitos dos camundongos KO β2; c) associado ao ISO não alterou as propriedades mecânicas nos cardiomiócitos dos camundongos KO β1 e reduziu nos cardiomiócitos dos camundongos KO β2. / The aim of this study was to investigate the effects of endurance training on cardiovascular parameters and morphological and mechanical properties of isolated cardiomyocytes from the left ventricle of β1-and β2 adrenergic receptors knockout mice. 4 months old C57BL/6J, β1- adrenergic receptor knockout (KO 1), FVB/N and β2-adrenergic receptor knockout (KO 2) mice were randomly allocated into one of the 8 groups: C57c, C57t, KO β1c, KO β1t, FVBc, FVBt, KO β2c e KO β2t. The animals of the trained groups (C57t, KO β1t, FVBt, KO β2t) underwent a protocol of aerobic training 8 weeks, 5 days/week, 1 hour/day, intensity of 60% of maximal speed. 3 to 4 animals in each group were divided for the analysis of cellular contraction with infusion of -adrenergic agonist isoproterenol (ISO) [100nM]. At sacrifice, the heart was removed and left ventricular myocytes were enzymatically dispersed. Cell length and width were measured using an image capture system and cell volume was calculated. Myocytes were stimulated at 1 Hz at controlled temperature (37oC) and cell contractility was measured by using an edge detection system. The results showed that KO 1 mice showed lower cell length compared to C57. The KO β2t group showed higher cell length compared to the KO β2c group. The training protocol increased the contraction amplitude, maximum contraction velocity and maximum relaxation velocity of cardiomyocytes of KO β1t and KO β2t animals. The ISO did not alter the amplitude of contraction, maximum contraction velocity and maximum relaxation velocity of cardiomyocytes from KO β1+ISO animals, while the KO β2+ISO animals showed an increase in the same mechanical properties. It is concluded that the aerobic training protocol: a) increased the mechanical properties of cardiomyocytes from KO β1t and KO β2t animals; b) increased the length of cardiomyocytes from β2 KO mice; c) associated with the ISO did not alter the mechanical properties of cardiomyocytes from β2 KO 1mice and reduced of cardiomyocytes from KO β2 mice.

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