School of Public Health
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The collections in this community comprise faculty research works, as well as graduate theses and dissertations.
Note: Prior to July 1, 2007, the School of Public Health was named the College of Health & Human Performance.
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Item THE INFLUENCE OF CUMULATIVE SLEEP RESTRICTION ON HUMAN PERFORMANCE: EXAMINATION OF BRAIN DYNAMICS AND SUSTAINED ATTENTION(2024) Kahl, Steven; Hatfield, Bradley; Kinesiology; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)Sustained attention (SA) impacts nearly every aspect of human performance. From the exactness of performing brain surgery to safely driving from one location to another, the ability to concentrate on a task for a period of time is important for success in work, school, relationships, and individual activities. As a key component of executive function (EF) and psychomotor performance, SA can be affected by many mental and physical processes. One process that can impact SA is restricted sleep, which is becoming more relevant in our ever-evolving technological society. Numerous studies have examined the impact of short bouts of restricted sleep on response time, a measure of SA, but few studies have examined the impact of the accumulating effect of sleep restriction (SR) on response time and brain dynamics as measured with electroencephalography (EEG). As part of a larger 40-day study, eight healthy participants (five female, average age 27.75) were observed for seven consecutive days and nights in a sleep lab, where they spent five hours in bed per night and engaged in numerous psychomotor vigilance tests (PVT), an indicator of SA, as part of their daytime activities. Through multiple one-factor ANOVAs, response time significantly slowed, and brain dynamic changes occurred, measured by slow wave activity (SWA) maxima change in the Fz electrode, located in the midline frontal region, over the course of the entire week of continual SR compared to an extended sleep night. Employing mixed method effects revealed a statistically significant relationship between response time and SWA maxima differences. The data show that not only does response time increase the day after rising first and last SWA maxima levels converge (i.e., flattening of the line slope connecting these values) caused by short bouts of SR, but these phenomena continue this progression with prolonged SR. Over the course of the week-long SR, the final SWA maximum increased at a higher rate than the first SWA maximum, leading to the maxima difference shrinking as response time increases. These findings indicate that brain dynamics highlight less restorative sleep occurring alongside a lack of sustained attention when sleep is restricted on a consistent basis.Item HIPPOCAMPAL GLUCOSE TRANSPORT AND OXIDATION IN RESPONSE TO DISRUPTED BLOOD FLOW IN AN AGING RAT MODEL OF HEART FAILURE(2023) Pena, Gabriel Santiago; Smith, J. Carson; Kuzmiak-Glancy, Sarah; Kinesiology; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)The primary objective of this dissertation was to investigate, in a rodent model of cardiovascular disease promoted by transverse aortic constriction (TAC), whether cerebral hypoperfusion stemming from chronic high pulsatile blood flow, and cerebral hypoperfusion stemming from low cerebral blood flow differentially affected hippocampal glucose transport and hippocampal mitochondrial function. We first, characterized the changes in right and left carotid hemodynamics and diameter in response to TAC and in a SHAM control group at three different time points (20-, 30-, and 40 weeks) post-surgery. Then, right, and left hippocampal mitochondrial content and substrate oxidation were investigated, and protein expression of glucose transporters and mitochondrial quality control markers were quantified. In this study, both the SHAM and TAC conditions included male and female rats to address possible sex differences. We report that all time points within TAC, right carotid blood flow velocities and pulsatility were greater than the left, but did not worsen over time. No differences in mitochondrial content were found within TAC nor between TAC and SHAM, but within TAC animals there were impairments in right hippocampal coupled and uncoupled respiration when compared to the left. When compared to the SHAM controls, right and left hippocampi of TAC animals had higher protein expression of mitochondrial quality control markers, but no differences in glucose transporter expression were found. Thus, while both high blood flow and/or pulsatility as well as low cerebral blood flow may lead to brain hypoperfusion, the metabolic consequences of the two may not be the same. The results from this dissertation contribute to the expanding literature characterizing the intersection between cardiovascular disease and neurodegeneration.Item Effects of exercise and inflammation on circulating microparticles(2024) Heilman, James; Prior, Steven J.; Kinesiology; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)Circulating microparticles (MPs), a subset of extracellular vesicles, have been implicated as novel biomarkers connected to vascular dysfunction. As such, they may contribute to atherosclerosis, hypertension, and other conditions leading to cardiovascular disease. MPs are involved in cell-to-cell communication in response to apoptosis and activation of the immune and inflammatory response, transferring their contents to nearby cells and effectively spreading each condition. The objective of this dissertation was to explore how circulating MP number and function are affected by stimuli such as diet and exercise. Our first study examined how post-prandial inflammation caused by a high-fat meal affects circulating MP number and function in young, healthy adults. We determined that a high fitness level may have a protective effect against the inflammatory load posed by a high-fat meal. The second study determined the effects of acute high-intensity interval aerobic exercise versus acute moderate intensity continuous aerobic exercise on circulating MP number and function in overweight versus lean recreationally active adults. We found that MPs and arterial stiffness in overweight individuals are differentially impacted by the type of acute exercise. Our findings suggest that overweight individuals undergo a greater inflammatory response following high-intensity exercise compared to lean. The third study investigated the effects of a 6-month aerobic exercise training program on circulating MP counts and function in previously sedentary older adults. While we found no effect of the exercise training program on MPs, we provide insight into how improvements in cardiovascular fitness as well as higher exercise intensities may be needed to see changes in MP number and function following aerobic exercise training in older adults. For the first time, we have shown that both dietary inflammation and acute exercise can significantly impact MP function. Furthermore, we have shown that fitness status and body composition play important roles in determining MP number and function after each stimulus. Our findings provide novel insight into how MPs contribute to various types of inflammation as well as how they may be used as biomarkers to measure the progression of cardiovascular disease.Item A CASE STUDY OF RED BULL’S USE OF SPORTING EVENTS IN THE NEOLIBERAL URBAN ENVIORNMENT(2024) Weber, Emilio; Andrews, David L.; Kinesiology; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)This project critically examines the ways in which city space and place are mobilized for capital interests through an examination of the global sports and energy drinks brand, Red Bull, and specifically its urban-based event strategies. The events such as the ones Red Bull hosts, alongside other spectacular urban projects have been prominent endeavors in which the lived experience of space has been reformulated by those who wield power and influence in the city. Informed by the contextual forces and logics of neoliberal urbanism, Red Bull strategically deploys the physical and symbolic reformulation of cities as an important aspect of its brand marketing strategy. The company, alongside local entities, impact the physical environment of the urban areas they occupy for the events. In addition, representations of places are presented and altered. These alterations of urban space and place have included an increased focus on spectacular consumption sites and experiences, in addition to the policing and surveillance of such spaces. Furthermore, this thesis offers analytical insight into the ways Red Bull’s urban strategizing is both and product and producer of the normalized neoliberal fabric that has come to envelope the contemporary US city: ultimately reproducing urban spaces which promote private profit and continue or exacerbate the inequalities felt in cities. Drawing from a range of interdisciplinary scholarship, I examine the relationship between, and impact of, sporting events hosted within the context of neoliberal cities. Deploying theoretical frameworks based in urban studies, neoliberalism, and critical geography informs the literature review and my research. This literature includes, but is not restricted to, physical cultural studies, urban studies, the sociology of sport, and event literature. Additionally, I utilize a case study method to examine the nature of the events within the urban and sport context they take place in. Completing field research and participant observation at three Red Bull sporting events, hosted in three distinct locales in June 2023, August 2023, and February 2024, I focus on the composition, meaning, affect, and experience of urban space, as created by the event itself, alongside marketing and promotional strategies of the company and cities in relation to these events. The research findings are divided into two empirical chapters, focused on the material and symbolic impacts upon urban space and place, respectively. I posit these findings as a normalized occupation of urban space, following the logics of neoliberalism and the event/content production of Red Bull. In conforming to neoliberal capitalist ideas focused on commercialized spectacle, these events simultaneously work to normalize this corporate use of urban space.Item CREATING A SOCIALLY JUST KINESIOLOGY: ADDRESSING ANTI-BLACKNESS IN THEORY, RESEARCH, AND PEDAGOGY(2024) Justin, Tori Alexis; Jette, Shannon; Kinesiology; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)Currently, the National Academy of Kinesiology (NAK) is striving to create a socially just kinesiology (DePauw, 2021). The NAK call to action is informed, in part, by emergent scholarship that examines how dominant approaches in kinesiology often discount the importance of developing anti-racist, critical, and equitable pedagogy (e.g., Armstrong, 2022). While this scholarship brings attention to kinesiology’s centering of whiteness and the persistent stereotyping of (in)active Black bodies, what is missing is an examination of how/if anti-Black explanations of corporeality manifest across differing spaces in contemporary kinesiology and, if present, what form(s) they take. My dissertation addresses the above-identified gap by using a three-manuscript model to examine three 'spaces’ of kinesiology: theoretical, research, and pedagogical.In manuscript 1 (Chapter 2), I engage Black feminist theory to critically evaluate the tenets of Physical Cultural Studies (PCS). In doing so, I identify a significant theoretical and empirical oversight in PCS scholarship, namely the tendency to reify white Eurocentric epistemo-logics and disregard Black feminist thought by emphasizing Black masculinity and white feminist imperatives in examinations of race and gender. To disrupt this practice, I propose a Black feminist informed reconceptualization of four principal PCS tenets (pedagogical, political, qualitative, and theoretical). Manuscript 2 (Chapter 3) delves into research spaces by investigating how notions of “race” and “racial difference” are constructed in cardiovascular health (CVH) and cardiorespiratory fitness (CRF) research. I conducted a scoping review to systematically identify original research articles (N=236) that included “race” in their examinations of CRF and CVH and then analyzed the sample to ascertain how each article approached “race” and “racial difference”. Key findings include: the majority (77.5%) of the studies did not define race; more than half of the studies (58.6%) compared Black and white racial groups in their examinations; 45.2% of the studies positioned white research participants as the ‘average’ or ‘normal’ in comparison to other racial groups; and only one article discussed the possible role of racism in relation to their identification of racial difference in an outcome of interest. These findings illustrate the need for CRF and CVH examinations to engage scientific best practice on how to research “race” and “racial differences” in ways that avoid reproducing racialized stereotypes. Manuscript 3 (Chapter 4) considers how Black women doctoral students experience pedagogical spaces of kinesiology departments. By conducting semi-structured open-ended interviews (N=10) with current and former Black women graduate students in kinesiology, I examine participants’ perspectives on how/if anti-Black explanations of corporeality inform kinesiology research practice and curriculum, and how the participants experience these pedagogies. Key themes identified are: kinesiological research tends to employ “colorblind research methods”; these methods contribute to monocultural and ahistorical understandings of (in)active bodies and health; and participants experience resistance to institutionally-backed attempts to disrupt white normativity. For kinesiology to transform into the socially just field that NAK is advocating, kinesiologists must consider how anti-Blackness can inadvertently manifest in their theories, research practices, and pedagogies. I provide practical suggestions throughout the dissertation on how to move toward change in each of these spaces.Item CARDIAC AND VASCULAR FUNCTIONAL RESPONSES TO β2-ADRENERGIC RECEPTOR STIMULATION: EFFECTS OF SEX, AGE AND HEART FAILURE(2024) Liu, Yuan; Kuzmiak-Glancy, Sarah SKG; Kinesiology; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)Proper cardiovascular function is necessary to regulate the flow of blood to different partsof the body in response to demand. The ability of the heart to increase the amount of blood pumped and the precise control of blood flow to the skeletal muscle are of critical importance during movement – whether during exercise or while performing activities of daily living. This dissertation aims to assess the functional responses of the cardiac and vascular systems to β2- adrenergic receptor stimulation and identify factors influencing their responsiveness. Utilizing rat models of aging and heart failure, we investigated how sex, age, and heart failure impact the cardiac and vasculature responses to β-adrenergic receptor stimulation. In the first Aim, we explored the influence of the presence of estrogen on heart rate, coronary flow rate, and oxygen consumption rate when stimulated with a β2-adrenergic receptor agonist in perfused hearts from young and old, male and female rats. The presence of estrogen rescued the blunted heart rate response to β2-adrenergic receptor stimulation seen in young female compared to young male hearts. Old male and female hearts showed blunted heart rate responses compared to their young sex-matched controls; however, old males and females were similar in their responsiveness to β- adrenergic stimulation. In the second Aim, we evaluated the effects of a rat model of pressureoverload induced heart failure on cardiac responsiveness to β2-adrenergic stimulation in male and female hearts, again in the absence and presence of estrogen. Failing male and female hearts had similar heart rate responses to their sham counterparts. Comparing to the sham control female heart, heart failure female hearts show an impaired coronary flow rate increase in response to β- adrenergic stimulation with presence of estrogen, despite similar increases in heart rate. Aim 3 focused on measuring vascular responsiveness of an isolated muscular artery to β-adrenergic and estrogen receptor stimulation in young and middle-aged, male and female rats. Female rats demonstrated augmented vasodilation responses to β-adrenergic receptor stimulation compared to males, and estrogen enhances artery vasodilation response to β-adrenergic receptor stimulation in young female rats. The primary goal was to investigate how the acute presence of estrogen affected cardiovascular regulation in young and old, male and female rats. Conducting experiments in young and old, male and female, heart failure and healthy rats uncovers how the acute presence of estrogen affects β-adrenergic receptor stimulation responsiveness in the ventricular myocardium and muscular artery vasculature. Our findings reveal sex differences in cardiac and vascular responses to β-adrenergic receptor stimulation, highlighting the influence of sex hormones, particularly estrogen in the regulation of the cardiovascular system. We propose these are due, at least in part, to the membrane estrogen receptor, GPR30, and its downstream signaling pathway. These insights contribute to a better understanding of estrogen's role in the acute regulation of cardiac and vascular function, informing future age and sex-specific treatments for cardiovascular diseases.Item A Healthy Relationship? The Entanglement of State, Corporate, and Labor Interests in Gender-based Violence Sport Policies(2023) Drafts-Johnson, Lilah; Jette, Shannon; Kinesiology; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)Gender-based violence (GBV) within professional sports made headlines in 2014 following the Ray Rice domestic violence incident, prompting a Congressional hearing with the four major men’s sports leagues in the United States. This hearing resulted in the implementation of several sport industry-wide policies addressing off-field conduct for players and employees, including ones specifically focused on interpersonal relationships. Despite the cultural prominence of corporate sport entities such as the National Football League, National Basketball Association, and Major League Baseball, in addition to the fervor for institutional accountability in the wake of the #MeToo movement, there has been limited academic scholarship examining the scope and efficacy of these policies (see Brown, 2016; Augelli & Kuennen, 2018) Drawing upon the findings of a thematic analysis of Senate Hearing 113-725: Addressing Domestic Violence in Professional Sports, this thesis utilized a governmentality analytic to critically analyze the motivations, assumptions, and tensions which underpinned the institutionalization of GBV policies in corporate sport. The findings demonstrate that while the parties present at the hearing problematized sport culture at large as a producer of GBV, their remarks characterized professional male athletes as perpetrators, reifying the idea of the “violent (Black) male athlete” and violence as an inherent trait in professional sport more generally. Instead of critically interrogating the structure of professional sport, legislators instead focused on expanding the governing capacity of sport leagues, and effectively the state, to discipline and punish perpetrators of GBV by encouraging the implementation of new extra-legal policies. I argue that this hearing reinforced the neoliberal entanglement of state, corporate, and non-profit actors in the movement to reduce GBV in society, strengthening the dependency that the state has on corporate social responsibility to solve leading public health issues, and compelling GBV advocates, activists, and scholars to engage with corporations in order to receive critical funding and legitimacy in their work. Meanwhile, suggested legislation to improve economic and workplace conditions for survivors was ignored as labor issues were positioned as oppositional to GBV accountability efforts. Through articulation and radical contextualism, this thesis sheds new insight into the origins and methods of corporate GBV policies in sport as well as the intricacies of contemporary neoliberal governance, and ultimately argues that the state response to GBV must shift from one of punishment and surveillance to one of preventative care through improved economic and labor conditions for all workers.Item UNDERSTANDING PSYCHOLOGICAL INFLUENCE ON HUMAN PERFORMANCE: THE ROLE OF CEREBRAL CORTICAL AND NEUROMUSCULAR ACTIVATION DURING MAXIMAL EXERTION KNEE EXTENSION(2023) Ginsberg, Andrew A; Hatfield, Bradley D; Kinesiology; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)The dissertation describes a programmatic research effort involving a series of studies (study one, two, three) to address the phenomenon of cognitive strategies facilitating and contributing to enhanced motor performance. Cognitive strategies consist of various mental approaches used before or during the execution of a motor task to improve performance. Psyching, one of the common strategies, typically involves a combination of elements intended to modify arousal and attentional focus to enhance performance. Prior findings within the sport psychology literature have revealed positive effects of psyching on performance, however, the underlying mechanisms of effect are not well understood. To further understand changes in musculoskeletal performance as a result of psyching, the present research used a multidimensional approach (psychological + psychophysiological + kinetic) by employing the measures of electroencephalography (EEG) - cortical activity, electromyography (EMG) - muscle activity, and isokinetic dynamometry - peak torque during maximal exertion to achieve peak torque of a dynamic knee-extension skeletal muscle action. In each of the three studies, participants performed the psychomotor task under three different preparatory strategies, a task-related attentional focus strategy and for comparative purposes mental arithmetic (MA) and reading comprehension (RC) strategies serving as attentional distractions. Participants were characterized as untrained. The results of Study One provide evidence that task-related attentional focus, compared to distracting attentional strategies, is associated with increased force production. The EEG results of study two provide further evidence suggesting that during preparation for movement, the task-related attentional focus distributed neural resources toward task-related regions and away from task-irrelevant regions. Such a phenomena is consistent with the notion of the alpha (i.e., inhibitory) gating as described by Jensen and Mazaheri (2010). A novel contribution of study two was the experimental manipulation of cognitive strategies (RC, MA, PSY) in order to isolate on the element of task-related attentional focus. The primary focus of the program of research was Study Three. Participants were characterized as expert (highly strength trained athletes) with a training status identified as advanced. An additional comparative “resting” condition was implemented to engage the degree of cortical arousal during the three kicking conditions. Individualized alpha power (IAF) as an index as inhibition was subjected to a 4 Strategy (EO, MA, RC, PSY) x 6 ROI (central, frontal, left temporal, right temporal, parietal, occipital) x 4 Time (-20 to -15 s, -15 to -10 s, -10 to -5 s, and -5 to 0 s relative to knee extension initiation) repeated-measures ANOVA. Integrated EMG (iEMG) was subjected to a 3 Strategy (MA, RC, PSY) x 3 Muscle (rectus femoris (RF), vastus medialis (VM) and vastus lateralis (VL)) x 2 Time (-1 to 0 s, 0 to +1 s, respectively corresponding to “pre” and “post” initiation of the knee extension) repeated-measures ANOVA. Peak Torque was subjected to a 4 Strategy (BL, MA, RC, PSY) one-way repeated-measure ANOVA. The BL strategy consisted of maximal exertion during an orientation session in the absence of attentional manipulation. Study three replicated and extended the results of study one and study two suggesting that the use of task-related attentional focus leads to better performance, via the influence of brain and muscle activity. More specifically, enhanced motor performance was achieved via the task-focus cognitive strategy through heightened localized brain activity. In the evaluation of elite athletes, it appears that motor cortex activation is robustly elevated compared to rest across all three strategies in the motor region. Accompanied by heightened inhibition in non-motor regions as a results of the task-related focus. EMG revealed that task-related attentional focus was associated with an increase of neuromuscular activation of the quadriceps muscles. Although beyond the scope of this research, a cascade of events provides a model for explaining the influence of cognitive strategies on maximal skeletal muscle performance. Namely, the focused brain dynamics associated with the task-related focus leads to elevated motor unit recruitment which translates to heightened musculoskeletal performance (peak torque). The findings of this research program extend the neural efficiency model of human performance and support the gating-by-inhibition phenomenon as a central factor. That is, the attentional focus translated to heightened localization of motor activity in the brain resulting in elevated performance.Item Effects of a High-Fat Meal on the Inflammatory Phenotype and Function of Monocytes(2023) Shoemaker, Madison; Prior, Steven J; Kinesiology; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)Cardiovascular disease (CVD) remains the leading cause of mortality throughout the world. Atherosclerosis, the buildup of plaque within the arteries, is the main cause of CVD. An early and essential step in the pathogenesis of atherosclerosis is the formation of foam cells, derived from lipid-laden macrophages that become trapped within the tunica intima. Macrophages, through the scavenger receptor CD36, take up a modified form of cholesterol, oxidized low-density lipoprotein (oxLDL), at a rapid rate, which causes them to become lipid-laden and trapped. Chronic inflammation causes endothelial damage and dysfunction, increasing the permeability to circulating LDL, which becomes oxidized within the arteries. Due to the difficulty of studying the macrophages within atherosclerotic plaque, recent research has shifted to the study of their biological precursor: monocytes. A high-fat meal (HFM), an experimental model used to assess postprandial inflammation, was used to assess the role of this HFM-induced inflammation on the likelihood of monocytes to eventually become foam cells. We also included an additional oxLDL ex vivo treatment to gain further insight into the potential “priming” effect of a single HFM. While there was a significant increase in the inflammatory cytokine tumor necrosis factor alpha (TNF-a) in response to the HFM, there were no significant changes in monocyte oxLDL uptake or cell surface marker expression. Future studies may want to examine the inflammatory role that higher concentrations of oxLDL may have or examine other postprandial markers of inflammation in an older or at-risk population.Item INFLAMMATORY MACROPHAGE REGULATION OF ANGIOGENESIS AND SKELETAL MUSCLE PHENOTYPES(2023) Evans, William Stuart; Prior, Steven J; Kinesiology; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)Chronic inflammation is a hallmark of cardiovascular disease; however, there is a lack of understanding of how systemic inflammation affects the peripheral skeletal muscle to potentially hasten frailty and functional declines in patients. The overarching objective of this dissertation was to determine whether this systemic inflammation is accompanied by macrophage infiltration of skeletal muscle and reductions in skeletal muscle capillarization and fiber size. Using animal models of a) heart failure (HF) induced by transverse aortic constriction (TAC), and b) skeletal muscle ischemia, this work illuminates changes that occur in skeletal muscle with cardiovascular disease-related inflammation. The first study demonstrated that pressure overload resulted in cardiac hypertrophy in male rats consistent with heart failure with preserved ejection fraction (HFpEF), while females did not show cardiac hypertrophy or HF. The second study demonstrated sex-specific differences in skeletal muscle, with TAC male rats exhibiting smaller fiber sizes and greater capillarization, and female TAC rats exhibiting lower capillarization than Sham counterparts. This study then investigated skeletal muscle macrophages to determine whether they might underly or contribute to these differences. There were fewer macrophages in the skeletal muscle of male TAC rats than male Sham rats, and macrophage conditioned medium from TAC rats produced less-developed capillary networks in an ex vivo, experimental assay. Finally, the third study investigated whether an acute bout of systemic inflammation, in the absence of HF, could alter the infiltration of macrophages, or skeletal muscle fiber size or capillarization. Hindlimb ischemia was used to induce acute, systemic inflammation that peaked after 1 day. This systemic inflammation increased the infiltration of macrophages into remote, non-ischemic skeletal muscle by day 7; however, muscle structure was preserved over this short time course. This dissertation demonstrates that cardiovascular disease-associated inflammation is linked with tissue-level changes in macrophages in a sex-specific manner. These changes accompany and may, over time, contribute to skeletal muscle fiber atrophy and changes in capillarization in cardiovascular disease patients.