Indiana University-Purdue University Indianapolis (IUPUI) / Various methods exist to measure physical activity (PA). Subjective methods, such as diaries and surveys are relatively inexpensive ways of measuring one’s PA; how ever, they are riddled with measurement error and bias due to self-report. Wearable accelerometers offer a noninvasive and objective measure of subjects’ PA and are now widely used in observational and clinical studies. Accelerometers record high frequency data and produce an unlabeled time series at the sub-second level. An important activity to identify from such data is walking, since it is often the only form of exercise for certain populations. While much work has been done to advance the use of accelerometers in public health research, methodology is needed for quan tifying the physical characteristics of different types of PA from the raw signal. In my dissertation, I advance the accelerometry research methodology in a three-paper sequence. The first paper is a novel application of functional linear models to model the physical characteristics of walking. We emphasize the signal processing used to prepare the data for analyses, and we apply the methods to a motivating dataset collected in an elder population. The second paper addresses the classification of PA. We designed an experiment and collected the data with the purpose of extracting useful and interpretable features for differentiating among walking, descending stairs, and ascending stairs. We build subject-specific classification models utilizing a tree based classifier. We evaluate the effects of sensor location and tuning parameters on the classification rate of these models. The third paper addresses the classification of walking types at the population level. We propose a robust normalization of features extracted for each subject and compare the model classification results to evaluate the effect of feature normalization. In summary, this work provides a framework for better use of accelerometers in the study of physical activity. / 2 years

Indiana University-Purdue University Indianapolis (IUPUI) / Efforts to encourage the medical community to prescribe exercise for disease prevention and management have increased significantly in recent years. In patients with obstructive sleep apnea (OSA), it is encouraging that exercise has been shown to improve sleep efficiency, daytime sleepiness, and disease severity. However, in order to better understand the dose-response relationship between exercise and OSA-related outcomes, accurate and reliable methods for assessing physical activity habits are needed. Purpose: To determine the test-retest reliability and validity of two self-report physical activity questionnaires [Physical Activity Vital Sign (PAVS); International Physical Activity Questionnaire-Short Form (IPAQ-SF)] in an OSA population. Methods: 39 adults with moderate-to-severe OSA wore an accelerometer for seven consecutive days and completed the PAVS and IPAQ-SF (twice within 10 d), along with questionnaires on quality of life, sleepiness, and treatment adherence. Test-retest reliability was determined using intraclass correlation coefficients (ICC). Criterion and construct validity were determined using Pearson (r) and Spearman correlation coefficients (ρ), respectively. Results: PAVS and IPAQ-SF scores were reported as total min/wk of moderate-vigorous physical activity (MVPA). Test-retest reliability for MVPA was excellent for PAVS (ICC = 0.982) and good for IPAQ-SF (ICC = 0.766). MVPA assessed via accelerometry was strongly correlated with PAVS (r = 0.802) and moderately with IPAQ-SF (r = 0.569). Both PAVS and IPAQ-SF were significantly correlated with body mass index (BMI) (ρ = -0.273 and -0.268, respectively), but no other variables. Conclusions: The PAVS and IPAQ-SF are reliable and valid PA questionnaires and may be utilized as a tool for accurately assessing physical activity levels in OSA patients.

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Abstract Human Immunodeficiency Virus (HIV), a chronic medical condition characterized by cycles of wellness and illness, has the potential to decrease the physical activity levels and functional independence of infected individuals. Although antiretroviral therapy has been credited with improving and maintaining the immune status of infected patients by increasing cluster of differention 4 (CD4) count and suppressing viral load, the short- and long-term side effects of antiretroviral medication and the possible negative impact of these side effects on physical well-being have not yet been fully investigated. Therefore, I assessed the relationship between CD4 count, habitual physical activity levels and functional independence in a group of HIV positive South African adults either taking or not taking antiretroviral medication. I also compared the aerobic capacity, muscle strength and physical activity levels (activity counts) of age-matched black HIV negative females and HIV positive females who were taking antiretroviral medication. For the first part of the study, a Lifestyle and Physical Activity Questionnaire was completed by 186 black* male and female HIV positive outpatients who were recruited from a Johannesburg based antiretroviral roll out site. Of these patients, 121 were on first line antiretroviral treatment (median time of seven months), and 65 patients were not taking any medication. The questionnaire, as well as recording HIV history and current CD4 count, assessed each patient’s ability to independently perform one or more tasks of daily living as well as his/her monthly occupational, household and recreational physical activity levels. From the subjects’ responses, a total metabolic equivalent (MET) score for one month was calculated. The second part of the study assessed the full blood counts, aerobic capacity (submaximal bicycle ergometer test), lower limb strength (isokinetic dynamometry), hand grip strength (hand dynamometer) and seven day physical activity counts (actigraphy) of ten HIV positive black females recruited from the same Johannesburg antiretroviral roll out site. All of these patients had been taking first line antiretroviral treatment for a median time period of seven months. Ten HIV negative age-matched black females acted as their controls. From the questionnaire, significant correlations were observed between CD4 count and length of time on antiretroviral medication (P < 0.0001; r = 0.45), and between CD4 count and total monthly physical activity level (P = 0.0067; r = 0.20). Patients who considered themselves functionally independent had a significantly higher CD4 count that those patients who required help from others (P = 0.0031). The second part of the study revealed no significant difference in aerobic capacity, lower limb muscle strength (peak torque), handgrip strength and seven day physical activity counts between the female HIV positive patients and HIV negative controls. My results show that the use of antiretroviral medication (median time of seven months) increases CD4 count which translates into an increased habitual physical activity level and greater sense of functional independence. I have also shown that HIV positive females who are taking antiretroviral medication have an aerobic capacity, leg strength, handgrip strength and physical activity count which is not statistically different to their HIV negative counterparts. In this sample, the side effects associated with the administration of antiretroviral medication did not negatively impact on physical well-being. However, more research needs to be conducted on the possible physical activity limiting side effects of longer term antiretroviral medication administration, which may limit habitual physical activity levels. * Footnote: Race does not refer to any biological attributes but rather to the compulsory classification of people into the Population Registration Act. Although the act has been amended, these categories are still powerful and commonly used by the South African Government and statistical services.

Background: As obesity continues to be a global epidemic, health professionals continue to search for effective intervention and prevention programs. As suggested early in the 20th century, sport participation creates an environment not only for one to be physically active at a particular moment, but also to cultivate and develop skills necessary to lead a physically active lifestyle across one’s lifespan. Further, sports can provide individuals with an ideal environment to cultivate the psychological constructs of resilience and self-efficacy, traits that can provide them with protective agents that support physical and mental health, thus promoting greater life satisfaction. Purpose: The purpose of this study was twofold: (1) to determine the impact of previous high school sport participation on college freshmen’s current levels of exercise self-efficacy, resilience, and psychological need satisfaction in exercise; and (2) to examine relationships between demographic variables and exercise self-efficacy, resilience, and psychological need satisfaction in exercise (PNSE). Methods: A cross-sectional, stratified random sampling technique was employed to collect responses from college freshmen across the country (n = 156) using a SurveyMonkey survey instrument. ANOVA and Kruskal-Wallis H tests were completed to examine differences, based on demographic and sports participation factors, on the constructs of exercise self-efficacy, resilience, and PNSE. Independent samples t tests were conducted with dichotomous demographic variables. Ordinary least squares (OLS) multiple linear regression modelling was completed to attempt to predict exercise self-efficacy, resilience, and PNSE scores for respondents based upon their demographic and sports participation variables. Results: The results of analyses indicated that both resilience and PNSE, but not self-efficacy, were associated with sports participation. High school GPA, total physical activity, having met moderate PA guidelines, and being a collegiate athlete were each associated with exercise self-efficacy. Furthermore, high school GPA, total physical activity, freshmen standing, and being a collegiate athlete were each associated with resilience. Lastly, total physical activity and moderate PA guidelines met were associated with PNSE. Conclusion: The findings of this study may support sports participation as a way to develop exercise self-efficacy, resilience, and PNSE. Collectively, these findings may support the development of a model for adolescent programming that could include the development of each of these constructs, the implications of which could positively affect both academic and athletic domains.

The overall aim of this dissertation was to better understand the learning and teaching of NBPA in PHE experiences for teachers and adolescent students. A secondary aim was to better understand the learning and teaching cycle for NBPA reform in PHE. To achieve these aims, I conducted three interrelated studies that explored: (a) how pre-service teachers learn to teach NBPA in PHE, (b) in-service educators’ perspectives on learning and teaching NBPA, and (c) adolescent student experiences with NBPAs in and beyond PHE. These three studies explored the learning cycle from pre-service instruction, to in-service professional development, to, finally, the impact on the students’ learning. Individual findings are discussed in each of the three studies, and two overarching themes are discussed as findings for the overall body of research: (a) NBPA as a conduit for place- and land-based education; and (b) NBPA as an effective form of PHE reform. / Graduate / 2023-07-07

Physical activity is associated with a host of health benefits across childhood. Despite this, most children are not engaging in enough physical activity to achieve health benefits, and there is growing evidence that lifelong physical activity habits may be established in childhood. Theories suggest that physical literacy may be associated with health benefits due to its reciprocal relationship with physical activity participation. The associations between physical literacy, physical activity and health in children remain largely unstudied. The purpose of this thesis was to explore the relationships between physical literacy, physical activity and health across early and middle childhood. The first study assessed the measurement properties of the Physical Literacy Assessment for Youth Tools, an assessment battery for physical literacy. We determined that this assessment had acceptable internal consistency, construct validity, and offered unique perspectives of a child’s physical literacy. We then determined that physical literacy was associated favourably with body composition, blood pressure, quality of life, and aerobic fitness in school-age children. Moderate-to-vigorous physical activity mediated the associations between physical literacy and aerobic fitness. Finally, the third study observed that physical activity trajectories from preschool to school-age were associated with school-age physical literacy. These results highlight the importance of physical literacy in childhood, given its associations with physical activity and health indicators. Physical literacy was associated with favourable health indicators, supporting its position as a determinant of health. The participants in the lowest physical activity trajectory groups had the lowest physical literacy. These finds suggest that physical activity across early and middle childhood may play a formative role in the development of physical literacy. Future work should determine if these results are applicable to other age groups, such as early years or adolescents, and if changes in physical activity over time are associated with changes in physical literacy over time. / Thesis / Doctor of Science (PhD) / Kids who are active every day will be healthier that those who aren’t. Unfortunately, most Canadian kids are not active enough to be healthy. We still don’t really know why some kids are active and some kids aren’t active. We think that physical literacy might be the missing piece to help kids be more active as they grow. This thesis studied the links between physical literacy, physical activity and health in kids. We found that we could measure physical literacy well in school-age kids. We also found that physical literacy was linked to health in kids. Kids who were the most active as they grew had the highest physical literacy. We saw that boys were more active than girls as they grew. Kids should start being active as preschoolers to help develop physical literacy. We need more programs and activities for kids to be more active to help develop physical literacy.

Introduction: The COVID-19 pandemic has resulted in higher-than-normal levels of anxiety and depression, especially among graduate students whose academic trajectory was disrupted. Physical activity and trait resiliency have both been shown to protect against stress-induced anxiety and depression during the pandemic. However, it remains unknown whether the same was true for graduate students and what biological mechanism, such as heart rate variability (HRV) might underpin these relationships. Method: We examined change in stress, current physical activity, and trait resiliency to identify key factors associated with better mental health outcomes in a national sample of graduate students (N = 61) who were recruited during the COVID-19 pandemic. We evaluated the unique contributions of change in graduate-school-related stress, physical activity (moderate, vigorous, and fitness), and trait resiliency to both anxiety and depression. We conducted moderation analyses to explore the processes through which these variables interact and mediation analyses to examine whether HRV was part of the underlying mechanism. Questionnaire were used to assess graduate-school-related stress, physical activity (moderate, vigorous), and trait resiliency. We estimated physical fitness using the six-minute walk test and captured resting HRV using a validated mobile application. Results: Graduate students reporting greater change in school-related stress were more anxious and depressed; however, those who engaged in more moderate physical activity were less anxious and those with higher trait resiliency were less anxious and depressed. Moderation analyses revealed a “stress threshold” for moderate physical activity whereby students who were more physically active were more protected from anxiety symptoms than their lower active peers; but this was only true for people whose stress levels increased a little or moderately but not for people whose stress levels increased a lot. In contrast, trait resiliency was shown to buffer against depression regardless of change in stress level. HRV did not mediate these relationships. Conclusion: Graduate students experienced significant mental strain during the COVID-19 pandemic, but physical activity and trait resiliency may be promising protective factors. / Thesis / Master of Science in Kinesiology

An increased prevalence and earlier onset of cardiovascular disease (CVD) occurs in persons with spinal cord injury (SCI); the higher risk may be explained by novel CVD risk factors of aerobic capacity and peripheral vascular structure and function. Physical inactivity likely contributes to the basis of increased CVD risk after SCI, however evidence on the effectiveness of exercise programs in attenuating CVD risk in SCI is insufficient. The present thesis evaluated novel CVD risk factors in a cohort of individuals with chronic SCI, and examined the effects of a single bout of exercise and exercise training on CVD risk. The first study demonstrated dramatic decreases in body composition, aerobic capacity, and sublesional endothelial function via flow-mediated dilation (FMD) in adults with chronic SCI vs. able-bodied (AB) controls. The second, third, and fourth studies assessed the role of shear rate (SR) patterns on FMD. Elevated retrograde SR had a detrimental effect on brachial and superficial-femoral-artery (SFA) FMD in both SCI and AB, but elevated anterograde SR had a favorable effect on SFA FMD in AB only. The fifth study demonstrated that sublesional vasculature does not respond to a 4-month combination aerobic and resistance-training program using the recently released physical activity guidelines for adults with SCI (PAG). The results of this thesis highlight the multilayered regulation of sublesional vasculature, and that it may respond differently to a single bout of exercise and exercise training when compared to an AB population. This information is crucial when designing strategies to combat impaired vascular structure and function after SCI. The results from this thesis also indicate the potential for the PAG to improve aspects of anthropometrics, body composition, and carotid vascular health in adults with SCI. Further investigations are necessary to delineate the effects of SCI itself, and of exercise, on CVD risk in this population. / Dissertation / Doctor of Science (PhD)