Kinesiology Theses and Dissertations
Permanent URI for this collectionhttp://hdl.handle.net/1903/2784
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Item What Makes "Fun" Fun? Insights into Children's Participation in Physical Activity(2015) Hopple, Christine J.; Andrews, David; Graham, George; Kinesiology; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)A rapidly accumulating body of literature points to fun as an important factor in the physical activity participation choices of children. Few studies, however, have conducted systematic, in-depth investigations into what children mean when they say an activity is fun. Scanlan and Lewthwaite’s (1986) Sport Enjoyment Model was used to guide this inquiry into children’s enjoyment of physical activity in the contexts of Physical Education, organized youth, and recreation. This descriptive, mixed-methods study involved a convenience sample of 98 fourth through sixth graders from six classes in three non-traditional public schools in a mid-Atlantic state. Data collection methods included focus group and duo interviews, an activity-related drawing, and a quantitative measure including both Likert and open-ended questions. Qualitative data was inductively analyzed using comparative analysis techniques with triangulation occurring across all data sources. Findings suggest that the reasons children gave for enjoying and not enjoying physical activity were numerous, varied, and compelling in nature. Although many factors were perceived similarly by many children, others were perceived quite differently. Thus, there appears to be an idiomatic tendency of fun – that is, what each individual child will perceive to be either fun or not is particular to that specific child, with some factors being more salient than others. Contextual factors also strongly influence whether a child will find a specific physical activity to be fun or not, to the extent that these appear to have a stronger influence on the enjoyability of an activity than the activity itself. Lastly, data-gathering methods used with children (activity-oriented questions and card-sorting during focus group interviews) were very effective at stimulating discussion amongst children and uncovering what they think in a very non-threatening manner. Taken together, then, results suggest that the reasons as to why any given child will find an activity to be fun or not fun are complex, interwoven, highly individualistic, and dependent upon a number of contextual factors. Results can aid key players in developing policies and programs which hold the potential to increase children’s enjoyment in physical activity while concurrently decreasing their non-enjoyment of activity.Item Variability in Cognitive Performance and Learning in Younger and Older Adults Explained by Cardiovascular Fitness, Physical Activity, and APOE Genotype(2013) Kayes, Maureen K.; Hatfield, Bradley D; Kinesiology; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)This dissertation investigated the association of physical activity with cognition in two cross-sectional studies. Physical activity has been positively associated with cognitive function, and in older adult populations has shown an additional benefit for carriers of the ApoE- å4 allele. Cognitive training has also revealed a benefit for improved cognitive performance. Questions remain, however, about the interaction of these factors in their relation with cognition. One study addressed the relationship between physical activity and cognitive performance during executive function and working memory challenges in adults ages 50-70, and the other explored the role that physical activity plays in learning in adults ages 22-50 undergoing an online cognitive training intervention. In both studies, regard for influence of the ApoE genotype was considered, and the concept of specificity of physical activity was explored through employment of measures of both cardiovascular fitness and weekly physical activity kilocalorie expenditure. The study of older adults revealed that performance on a working-memory task was positively related to weekly kilocalorie expenditure in APOE-å4 carriers, with no such benefit for non-carriers during a moderate challenge condition of the task, while a positive relationship was revealed for both å4 carriers and non-carriers during a more challenging condition, but the magnitude of the relationship was greater in å4 carriers. The study of younger adults revealed no transfer benefits for cognitive training; however, cardiovascular fitness was positively related to performance after the intervention on a transfer task of proactive interference, and a positive trend was also found for cardiovascular fitness on a divided-attention language vocabulary learning task. No association was observed with regard to APOE-å4 genotype for any post-intervention task or learning transfer challenge. Taken together, these studies reveal that physical activity is associated with improved cognition in younger and older adults alike, but with specificity as to volume or intensity of physical activity mediating the relationship, cognitive processes benefited, and the role that the APOE-å4 genotype plays.Item Circulating biomarkers of nitro-oxidative stress in young and older active and inactive men(2010) Bjork, Lori; Hagberg, James M; Kinesiology; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)Oxidative stress markers may be novel factors contributing to cardiovascular (CVD) risk. The purpose of this study was to examine the effects of long-term exercise, age, and their interaction on the plasma levels of the oxidative stress markers oxidized LDL (ox-LDL), nitrotyrosine, and myeloperoxidase (MPO), and to investigate whether these levels correlated with plasma NOx levels. Older (62 ± 2 yr) active (n=12) men who had exercised regularly for over 30 years and young (25 ± 4 yr) active (n=7) men who had exercised regularly for over 3 years were matched to older (n=11) and young (n=8) inactive males. Young subjects showed lower plasma nitrotyrosine levels than older subjects (P = 0.047). Young inactive subjects had higher ox-LDL levels than either the young active (P = 0.042) or the older active (P = 0.041) subjects. In addition, plasma oxidative stress levels, particularly ox-LDL, were correlated with various conventional CVD risk factors, and in older subjects were associated with Framingham risk score (r = 0.49, P = 0.015). The study found no relationships between plasma markers of oxidative stress and plasma NOx levels. The findings suggest that a sedentary lifestyle may be associated with higher ox-LDL levels and that the levels of oxidative stress markers may contribute to CVD risk.Item Exercise and Depression: Causal Sequence Using Cross-Lagged Panel Correlation Analysis(2009) Scott, Virginia Anne; Andrews, David L; Kinesiology; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)This study sought to determine what kind of causal relationship, if any, exists between exercise and depression. A university student population (N = 178) was given the Godin Leisure Time Exercise Questionnaire and the Beck Depression Inventory-II at two time points separated by approximately one month. Cross-lagged panel correlation was used to make causal inferences based on the strength of the temporal relationships. After meeting the assumptions of synchronicity and stationarity, there was no significant difference between the cross-lagged correlations (ZPF = -0.4599, p = 0.65). Thus, no single causal pathway was dominant. While equal cross-lagged correlations can indicate spuriousness, it can also signify reciprocal causation. Exercise was not clearly the cause of reductions in depression, but neither was depression clearly the cause of physical inactivity. More complex causal pathways, such as reciprocal causation, warrant further investigation.Item The Effects of Low-Fat Diet and Exercise on C-Reactive Protein and Metabolic Syndrome: Findings from a Randomized Controlled Trial(2008-07-09) Camhi, Sarah Michelle; Young, Deborah R; Kinesiology; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)Background: Low-fat diet (D) and exercise (E) are recommended for reducing cardiovascular disease risk. However, the independent and combined effects of D and E on C-reactive protein (CRP) and metabolic syndrome (MS) are unknown. Purpose: The purpose of this dissertation was to examine the changes in CRP and MS between control (C), D, E and diet plus exercise (D+E). Methods: Men (n=197) and postmenopausal women (n=180) with elevated low-density lipoprotein cholesterol and reduced high-density lipoprotein cholesterol, were randomized into a one-year trial with four groups: C, D, E or D+E (Stefanick et al., 1998). Weight loss was not an intervention focus. This secondary data analysis evaluated stored plasma samples for high-sensitivity CRP. MS prevalence was retrospectively found using the NCEP-ATP III definition. CRP change (ΔCRP) was examined between intervention groups using ANCOVA. Differences between groups for MS at follow-up were retrospectively investigated using logistic regression. All analyses were stratified by gender and controlled for baseline values, body fat change and other appropriate covariates. Results: In women, ΔCRP was different between D+E vs. C (-0.7 ± 0.33 mg/L, p = 0.04) and D+E vs. E (-0.9 ± 0.32 mg/L, p = 0.004). Women also had a decrease in CRP within D+E (Δ log CRP 0.2 ± 0.035 mg/L; p = 0.0002). After the intervention, ΔCRP did not differ for men between or within treatment groups. MS at follow-up was not different between C, D, E or D+E in either men or women. In women with MS, ΔCRP was different between D+E vs. C (-1.3 ± 0.43 mg/L; p = 0.006), D+E vs. E (-1.1 ± 0.44 mg/L; p = 0.02), and D vs. C (-1.2 ± 0.43 mg/L; p = 0.009). In women with MS, CRP decreased from baseline within D+E (Δ log CRP 0.2 ± 0.039 mg/L; p=0.0008). At follow-up, there were no differences between or within groups for ΔCRP in men with MS, or men without MS and women without MS. Conclusion: D and D+E may be effective treatments for reducing CRP in women with MS. Further studies are needed to replicate results and clarify the influence of gender.Item Effect of long-term exercise on endothelial progenitor cells in healthy humans(2008-04-24) Witkowski, Sarah; Hagberg, James M; Kinesiology; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)Endothelial progenitor cells (EPCs) are derived from the bone marrow and have been found to play a role in postnatal neovascularization and re-endothelialization. Reduced EPC number and function have been associated with death from cardiovascular diseases, CVD risk factors, and endothelial dysfunction. Oxidative stress, specifically, oxidized LDL (OxLDL) has been shown to decrease EPC number and function, and increase EPC senescence in vitro. Regular physical activity is related to lower rates of CVD; however the mechanisms underlying the benefits of exercise in the prevention of CVD are not fully clear. Exercise may improve the number, and function of EPCs while improving oxidative stress status. The primary purpose of this study was to compare CD34+/KDR+ EPC number, EPC clonogenic capacity, and senescence, in healthy men that have participated in greater than 20 years of moderate- to high-intensity exercise with low-active control subjects. To assess the effect of physical inactivity on these markers, a subset of exercisers (n=10) stopped exercising for 10 days after which, measures of EPC number, colony forming units, and senescence, endothelial function and oxidative stress were re-evaluated. Results showed that, CD34+/KDR+ cell number, CFU-Hill colonies, and EPC senescence were not statistically different between athlete and control groups. CD34+/KDR+ cell number was closely related to endothelial function. Specifically, the forearm blood flow response to reactive hyperemia was correlated with CD34+/KDR+ number in sedentary participants. Additionally, 5 athletes significantly decreased their CD34+/KDR+ number, which was related to a significant decline in endothelial function, indicating that regular physical activity is important for some athletes to maintain healthy endothelial function, perhaps through the maintenance of elevated number of circulating CD34+/KDR+ cells. CFU-Hill colony number was strongly correlated with hyperemic blood flow response in control participants and related to oxLDL independent of physical activity status. Athletes who participated in 10-days of exercise detraining demonstrated a significant decrease in EPC senescence, which was related to improved total antioxidant capacity. Overall, these results show that CD34+/KDR+ number is closely related to endothelial function. Moreover, the function of EPCs appears to be affected by oxidative stress and antioxidant availability.Item Factors Influencing the Implementation and Receptivity of a Physical Activity Intervention in Three Middle Schools(2006-09-26) Barr-Anderson, Daheia Julina; Young, Deborah R; Kinesiology; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)Introduction: Recent trials with adolescents have intervened to increase physical activity levels. Primary results report on the outcome (change in physical activity) with less focus on the evaluation of the intervention strategies and activities. This dissertation project presents an in-depth analysis of the extent to which Trial of Activity of Adolescent Girls (TAAG), a physical activity intervention targeting middle school girls, was implemented and received in three Maryland schools. Individual, social, and environmental factors were explored. Methods: Responses from select quantitative process evaluation data were used to assess dose, fidelity, and reach for each TAAG component. Information was integrated with data from nine focus groups with girls and 24 in-depth interviews with school staff, community partners, and TAAG university staff, who were key participants of the intervention activities. The focus group and interview data were analyzed using thematic methodology to identify key concepts, categories, and themes. Results: Implementation of the intervention varied by school and by intervention component. Qualitative interviews suggested that school differences could be attributed to school staff buy-in, administrative and faculty/staff support, and student behavior. Study staff implemented the intervention to teachers with higher levels of dose, fidelity, and reach than what teachers delivered to students. Notably, fidelity for physical education (PE) concepts and health education with activity challenges (HEAC) lessons was lower. Class observations indicated that PE objectives were observed 6% to 93% of the time, and 38% to 82% of HEAC lesson components were fully completed. Reasons reported by teachers for low fidelity were lack of time, administrative barriers, and limited space for activities. Reach for most components were high. Participation in after school programs ranged from approximately 9-22 girls. Girls reported lack of transportation, cost of programs, lack of interest, and time conflict as reasons for not joining programs. Conclusion: To maximize intervention efforts, it is important for researchers to decrease factors that negatively influence how well physical activity initiatives are executed as planned. Different data sources can provide information to better understand factors influencing program implementation.Item NFKB1 Gene Promoter Polymorphism and Unidirectional Laminar Shear Stress: Implications for NF-kB Activation, eNOS Protein Expression and Endothelial Function(2006-06-04) Park, Joon Young; Brown, Michael D.; Kinesiology; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)Exercise stimulus can be defined as endothelial wall shear stress. In the endothelial cells, the nuclear factor-kappa B (NF-κB) is an important intracellular signaling molecule by which changes in wall shear stress, sensed by mechanosensors, are transduced into the nucleus to initiate downstream eNOS gene expression. Recently, a polymorphism in the promoter region of the gene encoding a p50/p105 NF-κB subunit, NFKB1, has been identified. The NFKB1 ATTG insertion (I) / deletion (D) (NFKB1 I/D) promoter polymorphism transcriptionally regulates NFKB1 gene expression. However, the functional significance of this polymorphism has not been elucidated in endothelial cells under LSS and in endothelial function in humans. Therefore, the purpose of this study was to investigate whether the NFKB1 I/D promoter polymorphism had functional genetic properties in human umbilical vein endothelial cells (HUVECs) under physiological levels of unidirectional laminar shear stress (LSS), and further, whether the polymorphism was associated with changes in endothelial function after endurance exercise training in pre- and stage I hypertensive individuals. The major findings of the present study were that 1) a protein present in HUVECs preferentially and specifically binds to the I allele promoter compare to the D allele; 2) the I allele had significantly higher promoter activity than the D allele; and accordingly, the II homozygote cells had higher p50/p105 NFKB1 protein levels than the DD homozygote cells; 3) the II homozygote cells showed a greater increase in eNOS protein levels than the DD homozygote cells under unidirectional LSS; and 4) the I-allele carrier group had a greater reactive hyperemic forearm blood flow response, a measure of endothelial function, before exercise training; however, the NFKB1 I/D polymorphism was not significantly associated with the differential changes in endothelial function following exercise training. These results have potential clinical implications for endothelial dysfunction that are related to the development and progression of atherosclerosis and cardiovascular disease. In addition, our findings provide insight into the molecular mechanisms involved in the intracellular signaling transduction process of eNOS gene expression and function of the NFKB1 gene promoter region.