Recent evidence showing graduate students to be at an elevated risk of developing mental health problems has attracted the attention of both researchers and non-researchers (Evans, Bira, Gastelum, Weiss, and Vanderford, 2018; Flatherty, 2018). This increased risk could be attributed to the stressors graduate students routinely experience. However, few studies have examined the negative effects of work stressors among graduate students and ways to protect graduate students from the negative impact of stressors. This research explored the association between work stressors and the mental health of graduate students, while considering the potential protective role of physical activity. Also studied was the potential predictors of physical activity, such as social support for physical activity. Graduate students completed three surveys over a semester. Multilevel structural equation modeling was used to analyze within- and between-person variation. Increased levels of work stressors were associated with increased levels of mental health problems. Physical activity was not associated with improved mental health at both levels of analysis. However, higher levels of physical activity protected graduate students from the negative effects of role conflict and role ambiguity, but not work overload. Social support for physical activity and a mindset that stress is enhancing were both associated with increased physical activity. This is one of the first studies to not only consider the negative effects of work stressors on graduate students' mental health, but also the protective benefits of physical activity. / Doctor of Philosophy / Graduate school is a stressful time for many individuals. Graduate students are expected to do well in their classes while juggling other responsibilities, such as teaching, conducting research and/or working full-time to pay for school and living expenses. Although not everyone would consider graduate students to be full-time employees, it is not uncommon for graduate students to have long workdays and weekends that include completing work. Even if a graduate student does not clock into work every day, most are probably working more than the typical hourly employee. Not surprisingly, research has shown that graduate students are at increased risk of developing mental health problems when compared to the general population (Evans, Bira, Gastelum, Weiss, and Vanderford, 2018). These findings have even caught the attention of the national media, with some calling the mental health problem a crisis (Flatherty, 2018). Work stressors (i.e., parts of a person's job that lead to feelings of distress) may influence graduate students' mental health. However, few studies have examined the negative effects of work stressors among graduate students and factors that could protect graduate students from these negative effects. This study assessed the benefits of physical activity among graduate students, given the plethora of studies showing the positive benefits of physical activity. It is possible physical activity can reduce the negative effects of the work stressors experienced by graduate students, such as being overworked with teaching responsibilities or having to conduct multiple research studies at the same time. This study explored factors that might influence graduate students to be more physically active, such as social support for physical activity. Graduate students completed three surveys over a semester. Increased levels of work stressors were associated with increased levels of mental health problems. Graduate students who exercised more were "protected" from the negative effects of work stressors. In other words, even if graduate students were exposed to high levels of work stressors, they did not experience elevated mental health problems if they regularly exercised. Additionally, being around friends who promoted physical activity and having a mindset that stress is not bad but rather enhancing helped graduate students engage in more physical activity. Overall, the findings indicated that graduate students experience increased mental health problems due to negative work stressors, but by exercising they could reduce the negative effect of these work stressors.

Physical inactivity is a major cause of disease in the United States and globally. Effective physical activity interventions often use community based approaches due to the demonstrated effectiveness of combining individual and group based behavioral strategies towards encouraging physical activity behaviors and influencing social norms. Such interventions can increase their impact by adopting technology based solutions to facilitate the underlying behavioral strategies. Current technologies for persuading physical activity primarily focus on facilitating the individual level behavioral strategies and de-emphasize the interpersonal aspects. This dissertation focuses on the development and evaluation of technology that is aimed at facilitating group dynamics-based strategies for promoting physical activity within small socially connected teams. This dissertation introduces a multi-component smartwatch-centered system (FitAware) that uses sensors to automatically track physical activity and leverages the advantages of the watch form factor to facilitate both group and individual level behavioral strategies via non-interruptive, glanceable, and frequent feedback updates. This manuscript describes the design and evaluation of FitAware in the context of an 8 week statewide physical activity community-based intervention, culminating in guidelines for system development that have been tested in educational settings. / Ph. D. / Physical inactivity is a major cause of disease around the world. A good way to tackle this challenge is to conduct community-based physical activity interventions because of their effectiveness in the use of both individual and social approaches for influencing behaviors. An important challenge with such interventions is increasing their impact on the communities. Mobile technology can be used as a platform that can help reach more people. Mainstream devices for promoting physical activity focus on facilitating individual level behavioral strategies (e.g., how many steps one walked) and de-emphasize the interpersonal aspects (e.g., how ones steps compare to friend’s steps) which makes them less than optimal for facilitating the social approaches within community interventions. This dissertation focuses on the design, development and evaluation of a system that prioritizes both individual and interpersonal behavioral strategies for promoting physical activity. This work introduces a multi-component smartwatch-centered system (FitAware) that uses sensors to automatically track physical activity and leverages the convenience of the wristwatch information accessibility to facilitate both group and individual level behavioral strategies via non-interruptive, glanceable, and frequent feedback updates. This dissertation describes the design and evaluation of FitAware as part of an 8 week statewide physical activity community-based intervention, culminating in guidelines for system development that have been tested in educational settings.

The obesity epidemic has only soared to higher intensities in the past decade. The frightening part is that the proportion of obese children in society is greater than ever before. Many studies show the positive benefits of physical activity for children and adults alike. The medical community has recently accepted the fact that the brain can form more neural connections and physical activity aides the process. The majority of this study is dedicated to the good health, behavior, and academic excellence that can be achieved by elementary students if they are allowed to be physically active for at least forty-five minutes a day. The responsibility lies with the public school system. It is their job to ensure these requirements are met by adjusting the curriculum to allow time for physical activity.

Yes / Background: Stroke has been linked to a lack of physical activity; however, the extent of the association between inactive lifestyles and stroke risk has yet to be characterized across large populations. Purpose: This study aimed to explore the association between activity-related behaviors and stroke incidence. Methods: Data from 1999 to 2018 waves of the concurrent cross-sectional National Health and Nutrition Examination Survey (NHANES) were extracted. We analyzed participants characteristics and outcomes for all participants with data on whether they had a stroke or not and assessed how different forms of physical activity affect the incidence of disease. Results: Of the 102,578 individuals included, 3851 had a history of stroke. A range of activity-related behaviors was protective against stroke, including engaging in moderate-intensity work over the last 30 days (OR = 0.8, 95% CI = 0.7–0.9; P = 0.001) and vigorous-intensity work activities over the last 30 days (OR = 0.6, 95% CI = 0.5–0.8; P < 0.001), and muscle-strengthening exercises (OR = 0.6, 95% CI = 0.5–0.8; P < 0.001). Conversely, more than 4 h of daily TV, video, or computer use was positively associated with the likelihood of stroke (OR = 11.7, 95% CI = 2.1–219.2; P = 0.022). Conclusion: Different types, frequencies, and intensities of physical activity were associated with reduced stroke incidence, implying that there is an option for everyone. Daily or every other day activities are more critical in reducing stroke than reducing sedentary behavior duration.

Background: Dietary and serum antioxidants and physical activity can effect inflammation, which is associated with breast cancer risk and recurrence. This study investigated the relationship between diet, serum antioxidant capacity, physical activity, and inflammation in breast cancer survivors and individuals without cancer. Methods: Existing demographic, dietary intake, and physical activity data of 78 breast cancer survivors and 30 individuals without cancer from the Day and Night Study conducted at Virginia Commonwealth University were used. Participants were recruited from southern Virginia. Metabolic equivalents were calculated through type, intensity, and duration of physical activity. Dietary antioxidant intake (FRAP) was calculated from Harvard Food Frequency Questionnaire data. Serum samples were analyzed for inflammation (hsCRP,IL-6,IL-1,and TNF alpha) and serum antioxidant capacity (ORAC) at Virginia Tech. Results: Anthropometrics and inflammation were higher, and FRAP and ORAC lower in breast cancer survivors compared to individuals without cancer, although not significant. There was a significant direct relationship between FRAP and ORAC and inverse relationship between FRAP and hsCRP. Breast cancer survivors 6+ years since diagnosis showed significant direct FRAP and IL-1 association, and inverse ORAC and TNF-alpha association. BMI was directly associated with IL-6 and CRP. Inflammation was not associated with METs or weekly activity, although there was an increasing inverse relation between METs, IL-1 and TNF- α with increasing ORAC. Conclusion: There is a significant relationship between dietary antioxidant intake and serum antioxidant capacity and inflammation. Increased body mass index increases inflammation. Diets high in antioxidants and maintaining a healthy weight may help reduce inflammation in breast cancer survivors. / Master of Science / Background: Dietary and serum antioxidants and physical activity can effect inflammation, which is associated with breast cancer risk and recurrence. This study investigates the relationship between diet, serum antioxidant capacity, physical activity, and inflammation in breast cancer survivors and individuals without cancer. Methods: Demographic, dietary intake, and physical activity data of 78 breast cancer survivors and 30 individuals without cancer from the Day and Night Study conducted at Virginia Commonwealth University were used. Participants were recruited in southern Virginia. Metabolic equivalents, a measure of physical activity, were calculated from type, intensity, and duration of physical activity. Dietary antioxidant intake (FRAP) was calculated from Harvard Food Frequency Questionnaire data. Serum samples were analyzed for inflammation (hsCRP, IL-6, IL-1, and TNF-alpha) and serum antioxidant capacity (ORAC) at Virginia Tech. Results: Anthropometrics and inflammation were higher in breast cancer survivors while FRAP and ORAC were lower. Significance existed between dietary antioxidant intake and serum antioxidant capacity as well as dietary antioxidant intake and hsCRP. Higher body mass index was associated with increased inflammation. Breast cancer survivors 6+ years since diagnosis with higher dietary antioxidant intake had lower IL-1, and with serum antioxidant capacity and TNF-alpha. Conclusion: In this population there is a significant relationship between dietary and serum antioxidant capacity, as well as dietary antioxidant capacity and hsCRP. In breast cancer survivors 6+ years since diagnosis there are significant associations in antioxidant capacity and inflammation. This is evidence that dietary antioxidants and maintaining a healthy weight can help reduce inflammation.

Yes / Sedentary behaviour (SB) in childhood is a major public health concern. Little is known about ethnic differences in SB during school and holiday weeks among White British (WB) and South Asian (SA) children, which this study aims to address through investigating inclinometer measured SB and exploring reasons for child engagement in SB. A mixed methods study, comprising of a quantitative investigation with 160, 6-8 years old children and a qualitative study with a subsample of 18 children, six parents and eight teachers was undertaken. Children of WB and SA ethnicity in three schools were invited to wear inclinometers for seven school terms (summer/winter/spring) and seven holidays (winter/spring) days during July 2016-May 2017. Total SB, SB accumulated in bouts > 30 min and breaks in SB were explored using multivariate linear mixed effects models which adjusted for wear time, sex, deprivation, overweight status, season, term, weekday and school. Nine focus groups and two interviews were carried out using the Theoretical Domains Framework to explore SB perceptions among parents, teachers and children. Data were analysed using the Framework Approach. 104/160 children provided 836 valid days of data. Children spent on average eight hours of SB/day during term time and holidays, equating to 60% of their awake time, and had on average 111 SB breaks /day. SA children had 25 fewer SB breaks/ day when compared to WB (p / Funded by the NIHR Collaboration for Leadership in Applied Health Research and Care Yorkshire and Humber (NIHR CLAHRC YH).

This dissertation is organized in a traditional format while including three essays that address specific research questions. Essay 1 examined the relationship between physical activity and community engagement and their effect on mental well-being among older men and women. Data from National Health and Aging Trends Study (NHATS) from 2018 to 2020 were explored and the posited relationships were tested. This essay provides empirical support that older adults who are reasonably active and involved in the community have greater mental well-being than those who isolate themselves. Essay 2 provides insight into older adults' motivation to improve their physical activity through the use of a fitness tracker. The key finding from this study is that wearables, especially fitness trackers, can significantly facilitate increased physical activity. Essay 3 is a mixed-methods study to understand older adults' perception of the usefulness of fitness trackers and interaction with such devices. Findings suggest that to increase the adoption of fitness trackers among older adults, makers could improve the esthetics and quality of the wristband in addition to the battery life of the tracker.

Yes / The Pillar Integration Process was developed to facilitate integration of mixed method data, but there is limited historical application of this approach in complex intervention evaluation. To test the applicability of the technique, this paper presents two case studies examining the efficacy of a workplace intervention. The research included a pilot RCT and process evaluation. The case studies illustrate the benefits of applying the Pillar Integration Process to elicit a comprehensive understanding of intervention efficacy and to design better interventions. This paper contributes to the mixed methods research by advancing the technique through considering inherent philosophical assumptions, and evidencing the value of integrating methods within, as well as across, “qualitative” and “quantitative” categories. / Macmillan cancer support part-funded this research and were one of the participating organizations. Ergotron Inc. provided 25 sit-stand desks for use within this research. The research formed part of the lead author’s PhD study, which was funded by a School of Sport and Education, Brunel University London, PhD bursary.

Physical inactivity is a leading cause of death worldwide and contributes significantly to the burden of non-communicable diseases (NCDs). Physical inactivity has become a global pandemic with the highest prevalence in the region of the Americas. There is strong evidence on the effectiveness of community-based PA interventions, including behavioral and social interventions, campaigns and informational approaches, and policy and environmental modifications to increase physical activity at the population level. The purpose of this dissertation was to examine the impact of two types of community-based interventions to promote leisure-time physical activity using public spaces and their applicability and transferability from the Latin American to the US context. Specifically, three programs were examined: (1) Atlanta Streets Alive (ASA) (the Open Streets initiative inspired by the Bogota Ciclovia, hosted in the city of Atlanta, Georgia, US); (2) the Bogota Recreovia (free PA classes in community settings in the city of Bogota, Colombia); and, (3) Academia Fit (the PA-classes in community settings program adapted from the Brazilian ACP for Latino Communities in San Diego, California, US). This dissertation shows different assessment approaches including a descriptive study, a pre-post natural experiment with multiple control groups, and a translation and implementation study using an evidence-based approach such as the RE-AIM framework. Some of the overall findings include: community-based interventions implemented in public spaces such as Open Streets and PA-classes are promising for increasing moderate-to-vigorous PA (MVPA) on leisure-time within the communities where they are implemented. Besides, these interventions are effective to reach vulnerable populations including low income, women and ethnic minorities such as Hispanics in the US. Finally, the implementation of an Open Streets initiative and a free PA-classes program was feasible (applicable) in Atlanta, GA, in the US and San Diego, CA, respectively.

The prevalence of obesity is a growing problem for children and adolescents worldwide (Schwellnus & Derman, 2003:12; Verster, 2001:15; Cameron, 1999:75). Obesity contributes to primary and secondary health risks such as coronary heart disease and diabetes (Kalk, 2001:576). Obesity is inheritable as well as the health disorders associated with the type of obesity (Kalk, 2001:576; Dietz, 1995:157; Garfinkel & Cosina, 1990:511; Bouchard et a/., 1985:64). A possible cause for the increase of obesity is inactivity, and this generates numerous health problems for children and adolescents (Du Toit & Van der Merwe, 2003:49; Verster, 2001:15; Kalk,2001:576; Steinbeck, 2000:28; Cameron, 1999:75; Reilley et a/., 1999:217). Research has shown that regular exercise can lower the risk of obesity and have many health benefits in general (Deheeger et a/., 1997:375).Consequently the participation of physical activity is important for everyone not only for the obese individual (Van Mil et a/., 1999:842). Physical activity has physical as well as psychological benefits such as positive development in self-concept (Walters & Martin, 2000:51). A positive self-concept during adolescence can have an influence on mental and physical health, and the development of a positive self-concept is critical during the adolescent period (Park, 2003:42). Research also indicates that a strong self-concept can lead to an increase in participation physical activity (Park, 2003:47). Physical activity can also be a social opportunity during which self-concept and self-worth can develop (Marsh, 1997:28). The objective of this study firstly was to determine the influence of a 16-week physical activity intervention program on body composition and self-concept of black South African adolescents. The second objective was to determine the incidence of obesity among these adolescents. The third objective was to determine the influence of body composition on self-concept after participation in a 16-week physical activity intervention program. A total of 95 black adolescents (ages 13 to 18) were recruited to participate in the PLAY study (Physical Activity for the Youth). A control group of 24 adolescents did not participate in any exercise, where an experimental group of 71 adolescents did indeed participate in a 16-week physical activity intervention program. Anthropometric measurements and a comprehensive body composition were taken, using skin folds, BMl and the Bod Pod. The subjects completed a self-concept questionnaire (PASWIN2004 computer program). The findings in this study seems to indicate that there was a positive relationship, between physical activity and BMI as well as Bod Pod changes, after a 16-week activity intervention program in the experimental boys group. No further correlations were traced in the other groups. Among all the adolescents (experimental and control groups), were 80.85% overweight, of which 40.42% were classified as obese. This shows that the majority of this group of adolescents were overweight. No significant changes were found in body composition. The girls showed a slight increase in BMI as well as body fat percentage and a decrease in self-concept. This indicates that an increase in body fat can lead to a lower self-concept. / Thesis (M.Sc. (Human Movement Science))--North-West University, Potchefstroom Campus, 2006.