Kinesiology Theses and Dissertations

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Acts of Livelihood: Bodies and Nature in International Garden City Movement Planning, 1898-1937
(2018) Clevenger, Samuel Martin; Andrews, David L; Kinesiology; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)
Urban planning and reform scholars and policymakers continue to cite the “garden city” community model as a potential blueprint for planning environmentally sustainable, economically equitable, humane built environments. Articulated by the British social reformer Sir Ebenezer Howard and his 1898 book To-Morrow: A Peaceful Path to Real Reform, the model represented a method for uniting the benefits of town and country through a singular, pre-planned, “healthy” community, balancing spaces of “countryside” and “nature” with affordable, well-built housing and plentiful cultural attractions associated with city life. The book catalyzed an early twentieth-century international movement for the promotion and construction of garden cities. Howard’s garden city remains a highly influential context in the history of town planning and urban public health reform, as well as more recent environmentally-friendly urban design movements. To date, while historians have long examined the garden city as an agent of social and spatial reform, little analysis has been devoted to the role of prescribed embodiment and deemed “healthy” physical cultural forms and practices in the promotion and construction of garden cities as planned communities for “healthy living.” Informed by recent scholarship in Physical Cultural Studies (PCS), embodied environmental history, cultural materialism, and theories of modern biopower, this dissertation studies the cultural history of international garden city movement planning in early twentieth century Britain and the United States. Studying archival materials related to some of the prominent planners and resultant communities of the movement, I focus on the biopolitical dimensions of the planners’ contextual designs for “nature,” “health,” and “healthy” physical culture as they devised material garden city community layouts. I argue that the intentional British and American garden cities created during the movement were planned as spatialized strategies for the regeneration of laboring bodies through organized, bourgeois physical cultural practices and access to nostalgic spaces of “naturally healthy environments and outdoor recreation.
Aerobic Fitness and Prevalence of the Metabolic Syndrome in African Americans and non-African Americans in PREMIER: a randomized controlled trial
(2008-08-11) Levin, Laura A; Young, Deborah R; Kinesiology; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)
Background: The Metabolic Syndrome is the clustering of several cardiovascular risk factors for coronary heart disease and Type 2 Diabetes Mellitus. This syndrome is of public health importance due to its high prevalence and high correlation to all-cause, CHD, and CVD mortality. The purpose of the current study was to determine if a change in aerobic fitness in the treatment group significantly decreased the odds of Metabolic Syndrome at 6 and 18 months. Methods: There were 810 adult participants in this trial with above-optimal blood pressure and up to stage I hypertension. Participants were part of an advice-only control group or a treatment group where physical activity increases were the main component. Results: A change in aerobic fitness, independent of treatment status, was significantly associated with a decrease in prevalent Metabolic Syndrome at both 6 and 18 months (OR: 0.96, CI: 0.94 - 0.98 & OR: 0.96; CI: 0.94 - 0.98, respectively).
Age-related Difference in Kinematics and Cerebral Cortical Processes during Discrete Drawing Movements in Children and Adults
(2007-06-06) Pangelinan, Melissa Marie; Clark, Jane E; Kinesiology; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)
Research has shown developmental improvements in drawing movements during childhood. These changes may be related to protracted structural development and myelination of cortical brain structures underlying motor planning and control. However, no study to our knowledge has examined the relationship between cortical development and the emergence of accurate visuomotor behavior. This thesis characterized age-related differences in kinematics and cerebral cortical processes during the performance of discrete drawing movements in children, as compared to adults. Three groups were included in the study: young girls (6- to 7-year-olds), older girls (9- to 11-year-olds), and adult females (n=15, each). Participants performed 5cm center-out drawing movements with the dominant hand (right hand), while electroencephalography (EEG) was recorded. All participants exhibited similar task-related cortical communication (coherence) and activation (relative spectral power) in several frequency bands. Activation of motor neural resources (motor cortical potentials) in the midline pre-motor and motor regions was also similar across age groups. The similarity of the brain activation patterns for these measures may contribute to the comparable behavioral performance among all groups for root mean squared error (straightness) and movement length. However, other features of the young children's brain activation patterns and motor control were different than the older children and/or adults. Specifically, the young children showed increased activation of frontal (executive process) areas, whereas the older children and adults exhibit increased relative activation in task-relevant sensorimotor areas (as measured by spectral power) in frequencies related to sensorimotor processes and attention. Similarly, increased coherence in the lower beta and gamma bands, indicative of local networking, was found in the adults between the frontal and central regions, and the frontal and parietal areas. Moreover, the adults show increased activation of the contralateral sensorimotor areas time-locked to the onset of movement, compared with the young children. The increased activation of the motor areas and visuomotor networks during movement planning may contribute to faster, smoother, and more consistent behavioral performance for the older children and adults, not evident in the young children.
Aging Related Differences in Hand Intrinsic and Extrinsic Muscles for Hand Dexterity: An MRI Investigation
(2009) Hsu, Jeffrey; Shim, Jae Kun; Kinesiology; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)
Hand dexterity is crucial for humans to interactions with the external environment. Many activities of daily living (ADLs) such as pressing, grasping, writing and typing would be unattainable without a skillfully and proficiently functioning hand. Sexagenarians and older often experience difficulties in hand dexterity, which seriously impair their ability to perform ADLs. This study described the aging-related changes in hand muscle size and dexterity; and addressed the conflicting literature regarding the extent of atrophy to either the intrinsic or extrinsic hand muscles in the elderly. The overall hypotheses for this study were 1) that elderly adults show an aging-related decrease in hand muscle size and strength, especially a greater decrease in the intrinsic hand muscles, 2) elderly adults show an aging-related decrease in hand dexterity and 3) hand muscle size and strength are positively related to hand dexterity. This study examined hand muscle sizes with magnetic resonance imaging (MRI) and examined hand strength and other functional measures. This study found aging-related decreases in muscle size, muscle strength, hand dexterity. Furthermore, intrinsic muscles showed a greater aging-related decrease in volume and strength as compared to the extrinsic muscles. When examining relationships, muscle strength was positively correlated to multi-finger synergy and finger dependence. Also, muscle size was positively related to performance on clinical hand dexterity tests. This supports the strength-dexterity equivalence hypothesis.
ALLOSTATIC LOAD INFLUENCES VASCULAR FUNCTION AND SYMPATHOLYSIS IN YOUNG BLACK ADULTS
(2024) Eagan, Lauren Elizabeth; Ranadive, Sushant M; Kinesiology; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)
In the U.S., Black individuals tend to face a disproportionately higher risk for hypertension. This is largely attributed to chronic sympathetic activation induced by heightened exposure to psychosocial stressors. Allostatic load (AL), an index of cumulative physiological dysfunction from chronic stress, is associated with hypertensive risk and is also heightened in Black adults compared to those of other racial groups. Indeed, increased sympathetic activity is a hallmark characteristic of both hypertension and AL. The inability to blunt sympathetic-induced vasoconstriction during exercise (impaired functional sympatholysis) is also associated with hypertension. This dissertation aimed to investigate whether AL was associated with measures of vascular health in young Black adults, both at rest and during a sympathetic stressor. In our first study, we examined associations between AL and indices of vascular function and structure among young Black adults at rest, finding that higher AL was associated with greater macrovascular dysfunction and amplified wave-reflections. Additionally, we identified significant correlations among greater self-perceived stress with smaller brachial artery diameters and greater wave-reflections. The second aim of this dissertation focused on the associations between AL and the magnitude of functional sympatholysis among this population. Results indicated a positive association between AL and functional sympatholysis, with amplified sympatholytic responses among young Black females, as compared to their male counterparts, when forearm volume was controlled for. Overall, our findings suggest that elevated AL might predict macrovascular dysfunction at rest, with larger arterial diameters potentially compensating for chronic stress. These adaptive mechanisms, commonly observed in aging and diseased states, may also explain the positive correlations between AL and the functional sympatholytic response in young Black adults. Our consistent observations of the redundant vascular mechanisms among young Black adults allowing for adaptation to chronic stress strengthen our findings and further highlight the complex interplay between stress and cardiovascular health in Black adults.
Alterations in human skeletal muscle proteins in amyotrophic lateral sclerosis
(2015) DeRusso, Alicia Lauren; Chin, Eva; Kinesiology; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)
Amyotrophic lateral sclerosis (ALS) is the most common fatal neurodegenerative disease, resulting in loss of voluntary muscle control, atrophy, paralysis, and eventually death. Although the pathophysiology of ALS is not completely understood, recent research in Dr. Chin's lab has identified alterations in skeletal muscle proteins in ALS mice. The purpose of this study was to investigate alterations in proteins involved in calcium handling (SERCA1 and SERCA2), endoplasmic reticulum (ER) stress (Grp78/BiP, PDI, and CHOP) and protein synthesis (Akt) in human ALS skeletal muscle. The ER chaperone protein Grp78/BiP and Akt, a protein involved in protein synthesis, were higher in ALS compared to CON. The calcium pump SERCA1 was lower in diaphragm compared to quadriceps muscles of ALS cases. These data highlight alterations in skeletal muscle proteins not only between ALS and CON, but also between different muscles in ALS, which are helpful for informing future research study designs.
Alterations in the myogenic capacity of satellite cells in a mouse model of ALS
(2012) English, Samuel A; Chin, Eva R; Kinesiology; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)
Amyotrophic lateral sclerosis (ALS), also known as Lou Gehrig's disease, is a devastating neurodegenerative disease that results in pervasive muscle wasting, paralysis, and ultimately death. Recent research efforts have been made to characterize skeletal muscle in the disease, with some evidence suggesting that the tissue may contribute to ALS pathogenesis. Therefore this study was undertaken to continue to describe ALS skeletal muscle, specifically a population of skeletal muscle-specific stem cells known as satellite cells that play a role in regeneration following injury. Satellite cells were isolated and cultured from mutant mice (SOD1 G93A) that recapitulate the disease, assessed for the capacity to differentiate and proliferate, and compared to age-matched control cultures. SOD1 G93A cultures exhibited decreased expression of transcription factors associated with differentiation (i.e. MyoD and myogenin) compared to control cultures, as well as a reduced ability to proliferate in vitro. These results indicate that the satellite cell population in a mouse model of ALS displays dysfunctional myogenic capacity in vitro, and thus may contribute to the atrophic pathology seen in the disease.
America's Sweethearts? A Feminist Discourse Analysis of Dallas Cowboys Cheerleaders: Making The Team
(2022) Nowosatka, Lauren Riley; Jette, Shannon L.; Kinesiology; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)
The “often imitated, never equaled” Dallas Cowboys Cheerleaders (DCCs) are self-proclaimed as “the premier cheerleading squad in the world,” universally setting the stage (field) for professional cheerleading. In 2006, “America’s Sweethearts” launched a hit reality television (TV) show, Dallas Cowboys Cheerleaders: Making The Team (DCCs: MTT), where the squad director positions the organization as empowering women in the opening the series’ 13th season. Taking this seemingly contradictory statement—made during the #MeToo moment of 2018—as a department point, this thesis examines the constructions of femininity and empowerment on offer in season 13 of DCCs: MTT. A textual analysis adopted from Johnson et al.’s (2004) reading for dominance methodology, with a theoretical foundation in feminist discourse analysis and intersectionality, was used to examine season 13 of DCCs: MTT, answering the following questions: 1. What versions of femininity are on offer to viewers of Dallas Cowboys Cheerleaders: Making The Team? How do they intersect with race, sexuality, class, ability, etc.? 2. How is empowerment constructed through Dallas Cowboys Cheerleaders: Making The Team? Findings suggest that performances of femininity are aligned with emphasized femininity and ambassadorship, offering a homogenous image to viewers that idealizes and reinforces hegemonic beauty standards, the thin-ideal, and the objectification of women, paired with displays of emotional expressions, “intelligence,” and poise that subjectively position the cheerleaders within the larger patriarchal, late-capitalist Dallas Cowboys and NFL structures. Supposedly empowering to the cheerleaders, the discursive practices, enforced performativities, and productional strategies displayed on season 13 of DCCs: MTT, frames the institution as faux-empowering, endorsing empowerment as the product of making “correct” individual choices. Consequently, cheerleaders and viewers who do not make these decisions are rendered disempowered and made to feel shameful, contradicting the spirited nature of the sport. This thesis seeks to fill the gap created by the lack of critical, sociological discussions of professional cheerleading as a spectacle of late-capitalist, uber sport, permeated through popular culture and which analyzes professional cheerleading through the site of reality TV.
ANDROGEN RECEPTOR POLYGLUTAMINE REPEAT LENGTH AFFECTS RECEPTOR ACTIVITY AND C2C12 CELL MYOGENIC POTENTIAL
(2010) Sheppard, Ryan Lance; Roth, Stephen M; Kinesiology; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)
Testosterone (T) has a strong anabolic effect on skeletal muscle and is believed to exert its local effects via the androgen receptor (AR). The AR harbors a polymorphic stretch of glutamine repeats demonstrated to inversely affect receptor transcriptional activity in prostate and kidney cells. However, longer AR glutamine repeat lengths are associated with greater lean body mass and higher serum T in humans. The effects of AR glutamine repeat length on skeletal muscle are unknown. Purpose:To determine the effects of AR glutamine repeat length on AR function in skeletal muscle cells. Methods:AR expression vectors carrying 14, 24, and 33 glutamine repeats, respectively, were constructed and AR transcriptional activity was determined in transfected C2C12 myoblasts using an AR sensor plasmid. Each vector was subsequently stably transfected into C2C12 cells to create 3 independent cell lines: C2C12AR14, C2C12AR24, and C2C12AR33. Cellular proliferation and creatine kinase (CK) activity were determined. Gene expression was assessed via RT-PCR. Myosin expression, myotube formation, and myonuclear fusion index were examined immunohistochemically. Results: Transcriptional activity increased with increasing repeat length (3.91±0.26 vs. 25.21±1.72 vs. 36.08±3.22 relative light units in AR14, AR24, and AR33, respectively; p<0.001), in response to T. Ligand activation ratio indicated significant ligand-independent AR transcriptional activity. Significant AR protein expression was only detected in AR14 myoblasts. In contrast, AR mRNA expression was elevated in each stable line in the myoblast stage and throughout differentiation. The proliferation of AR33 cells was significantly decreased vs. AR14 (20512.3±1024.0 vs. 27604.17±1425.3, p<0.001) after 3 days. The CK activity of AR14 cells was decreased in comparison to AR24 and AR33 cells (54.9±2.9 vs. 68.3±2.2 and 70.8±8.1 units/μg protein, respectively; p<0.05) after 5 days of differentiation. The myonuclear fusion index was lower for both AR14 (15.21±3.24%, p<0.001) and AR33 (9.97±3.14%, p<0.001) in comparison to WT C2C12 cells (35.07±5.60%). Both AR14 and AR33 cells displayed atypical myotube morphology. RT-PCR revealed differences in the expression of genes involved in differentiation, cell fusion, and cell cycle progression. Conclusion: AR polyglutamine repeat length affects receptor activity and alters the growth and development of C2C12 cells. This polymorphism may explain some of the heritability of muscle mass in humans.
Arousal and skilled motor performance: The mediating role of cerebral cortical dynamics
(2006-08-16) Rietschel, Jeremy Carl; Hatfield, Bradley D; Kinesiology; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)
Despite achievement of a highly skilled level of motor competence, elucidation of the multiple factors contributing to variability of motor performance remains somewhat enigmatic. The inverted-U hypothesis posits moderate levels of arousal as essential to optimal performance; this suggests that arousal may be a key player of this variability. The purpose of this study was to examine the psychophysiological concomitants of moderate as compared to low arousal. Specifically we hypothesized a decrease in coherence between the temporal lobes (T3-verbal-analytical processing & T4-visuo-spatial processing) and the motor planning region (Fz), accompanied by an increase in task performance. Fifteen college undergraduates (9 females, 6 males, mean age = 23.4, SD = 4.22) participated in two days of testing. Day one consisted of 340 trials of a novel visuomotor pointing task to achieve task competency. On the second day, EEG data were recorded during both a Performance Alone (PA) condition vs. a Social-Evaluation and Competition (SE&C) condition, which were counterbalanced. Coherence estimates were subjected to a 2 x 2 ANOVA comparing Condition x Hemisphere; post hoc testing was completed using paired-t tests. The arousal-manipulation check of the two experimental protocols (PA vs. SE&C) provided by the autonomic measures and self-reports indicated an increase from a low to moderate level of arousal during the SE&C condition. There was a statistical interaction between condition and hemisphere revealing reduced coherence during SE&C only between T4-Fz (t(14) = 3.084, p = 0.008). Additionally, there was a increase in motor performance (t(13) = 2.171, p = 0.049). Consistent with the inverted-U hypothesis and our predictions as stated for moderate arousal relative to performing alone, there was a subsequent increase in performance coupled with a decrease in coherence between the visuo-spatial and the motor-planning regions. In light of the significantly improved kinematics, the reduction in networking between these task relevant areas is seen as an adaptive refinement of cortico-cortical communication as one moves from low towards optimal arousal.
Association Between ACE Genotype and Skeletal Muscle Strength and Volume, and Their Response to Strength Training in Older Adults
(2007-06-29) Charbonneau, David; Roth, Stephen; Kinesiology; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)
Introduction: Previous studies have linked an insertion/deletion polymorphism in the angiotensin-converting enzyme (ACE) gene with variability in the response of muscle strength and mass to strength training, though conclusions have been inconsistent across investigations. The purpose of this study was to investigate the possible association between ACE genotype and skeletal muscle strength and volume, and their adaptation to strength training. Methods: A group of older, sedentary adults completed 10-weeks of strength training. Quadriceps muscle strength and volume were measured using one repetition maximum and computed tomography, respectively. Differences were compared among ACE genotype groups (II vs. ID+DD) by sex and race. Results: Baseline and post-training, skeletal muscle strength and volume were not significantly correlated with ACE genotype. ACE genotype was significantly associated with muscle hypertrophy in Caucasian males only (p=0.02). Conclusions: The ACE genotype was not associated with skeletal muscle strength, but was associated with muscle hypertrophy in Caucasian males.
Association between increased hepatic lipid storage and impaired hepatic mitochondrial function in ovariectomized mice
(2012) Valencia, Ana Patricia; Spangenburg, Espen E; Kinesiology; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)
Reduced ovarian function is associated with development of the metabolic syndrome (MetS). Increased risk for MetS is strongly linked to hepatic metabolic dysfunction. However, at this time few studies have examined metabolic function of hepatic tissue under conditions of reduced ovarian function. The purpose of this study was to determine if ovariectomy (OVX) impaired hepatic mitochondrial function and its potential association with sirtuin (SIRT) function. Female C57BL/6 mice were divided into two groups (SHAM, OVX). Hepatic mitochondrial function was measured by assessing oxygen consumption, reactive oxygen species (ROS) production, and mitochondrial protein content. In addition, mitochondrial acetylation status and SIRT protein content was determined. The OVX group exhibited increased ROS production compared to the SHAM group. However, no differences were detected in oxygen consumption, mitochondrial protein content, acetylation status, or total SIRT content between groups. The data shows that ovariectomy increases mitochondrial ROS production, which suggests a novel mechanism to consider.
Associations between Classical Music, Physical Activity and Symptoms of Depression in Older Adults during the COVID-19 Pandemic
(2023) Arnold-Nedimala, Naomi A; Smith, J Carson; Kinesiology; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)
Background: The initial lockdown in March 2020 due to COVID-19 rattled the residents of North America as normalcy came to a standstill, freedom was stripped away, and people were forced to adapt to new restrictions and regulations, simply to survive. The elderly population was greatly affected by the lockdown as it prohibited those living in assisted living facilities to physically interact with family and friends highlighting the need to identify protective behaviors against mental health and depression. The neurological benefits of listening to classical music is an emerging area of research. A few studies suggest the positive outcomes of listening to classical music in reducing symptoms of depression. Additionally, while the cardiovascular benefits of exercise are well known, the impact of exercise on affect continues to be an emerging area of research. Purpose: The purpose of this study is to understand the efficacy of listening to classical music in attenuating symptoms of depression in older adults (50 – 90+) utilizing data collected from 3 separate time points during the COVID-19 pandemic, and to determine if physical activity is associated with providing additional benefit to lowering symptoms of depression Methods: A survey including the Geriatric Depression Scale (GDS), the Physical Activity Scale for the Elderly (PASE), and questions about listening to music (classical, Broadway, Christian music), and the frequency of listening to music was generated and distributed to people living in the United States and Canada immediately following the initial COVID-19 lockdown in April 2020. Informed consent was obtained prior to completing the survey, and participants who were interested in receiving a follow-up survey were asked to provide their email addresses. The follow-up surveys were generated 4-months (August 2020) and one year (April 2021) after the initial survey. Results: At the initial onset of the COVID-19 lockdown in April 2020, significant associations were observed between classical music listening (CML) and lower symptoms of depression, physical activity (PA) and lower symptoms of depression, music listening frequency, and lower symptoms of depression. In August 2020 and April 2021, significant associations were found between physical activity and lower symptoms of depression. However, no associations were observed between classical music listening and lower symptoms of depression, and music listening frequency and lower symptoms Additionally, significant associations were observed between age and lower symptoms of depression, sex, and lower symptoms of depression at all three time points. Conclusion: The results from our study suggest that there is an association between classical music listening and symptoms of depression, physical activity and symptoms of depression, music listening frequency and symptoms of depression in older adults (50+) during the early stages of the COVID-19 pandemic (April 2020). Additionally, the association between physical activity and symptoms of depression was maintained throughout the first year of the pandemic as supported by the data collected in August 2020 (4 months) and April 2021 (12-months).
Baseball, Citizenship, and National Identity in George W. Bush's America
(2008-11-21) King-White, Ryan E; Andrews, David L.; Kinesiology; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)
The four separate, but related, studies within this research project seek to offer a critical understanding for how American national identit(ies), and particular forms of (cultural) citizenship are discursively constructed and performed in and through the sport of baseball. More specifically, this dissertation will utilize and expand upon critical theories of neoliberalism, citizenship, whiteness, and (physical) cultural studies to engage various empirical sites, which help provide the context for everyday life in contemporary America. Each chapter looks at various empirical aspects of the Little League World Series and the fans of the Boston Red Sox (popularly referred to as Red Sox Nation) that have historically privileged particular performances and behaviors often associated with white, American, heterosexual, upper-middle class, masculine subject-positions. In the first instance this project also attempts to describe how 'normalized' American citizenship is being (re)shaped in and through the sport of baseball. Secondly, I aim to critically evaluate claims made by both Little League Baseball, and the Boston Red Sox organization, in response to (popular) criticisms (Bryant, 20002; Mosher, 2001a, 2001b, 2001c) of regressive activity and behavior historically related to their organizations, that they are striving for a more culturally diverse and welcoming condition for all through their tournament and fan community respectively. To best articulate this critical understanding of the cotemporary moment I analyzed the production of the 2003 Little League Worlds Series, the (multi)media discourses surrounding Dominican star/villain, Danny Almonte, the filmic rendering of 'normalized' members of Red Sox Nation within Good Will Hunting and Fever Pitch, and finally an ethnographic study of Red Sox Nation throughout the 2007 baseball season. In following Andrews (2008) suggestive outline for a Physical Cultural Study I used a multi-methodological, qualitatively based, study to gather evidence through which to best understand the socio-political context of the contemporary moment. In so doing, I hope to clarify the dangerous way neoliberal capitalism is practiced and experienced in America.
Beyond the Beauty Salon: Sport, Women of Color and Their Hair
(2011) Collins, Jennifer Elizabeth; Schultz, Jaime; Kinesiology; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)
Research concerning women of color in sport tends to center around several topics: barriers to participation, racial stereotyping, symbolic annihilation, and the intersecting axes of power that influence their involvement and representation. Furthermore, while there exists a rich body of literature that hair has inspired in black feminist scholarship, these works have overlooked the experiences of black female athletes. In this project I seek to bridge these two bodies of knowledge through focus groups and personal interviews with black female collegiate athletes. Specifically, I examine three issues related to hair in the context of black women's athletic experiences: 1) as a particular racialized, gendered, and sexualized expression of self; 2) as a signifier of "other" in sport and society; and 3) as a possible cultural barrier to specific athletic endeavors. By bridging the disconnect between the two fields, I will address the ways that hair is an embodied cultural form influencing the physical culture of women of color.
BIOLOGICAL AND FUNCTIONAL CHANGES IN SUPRASPINATUS MUSCLE AFTER ROTATOR CUFF TEAR
(2017) Valencia, Ana Patricia; Spangenburg, Espen E; Hagberg, James M; Kinesiology; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)
Rotator cuff (RTC) tears impair upper limb mobility and affect 20% of the adult population. Unfortunately, surgical repair of major RTC tears often fails to restore shoulder function and has a high risk of re-tear. RTC tears induce irreversible, degenerative changes to the muscle that may hinder the recovery of shoulder function. Currently, very few studies have comprehensively assessed RTC muscle function, thus, little is known about which markers may be able predict changes in function after RTC tear. In this dissertation, I present three studies designed to systemically determine the impact of a RTC tear on contractile function of the supraspinatus (SS), the muscle most commonly affected in the RTC. In study #1 I developed a novel method to test in vivo SS contractile function using animal species common to RTC research. In study #2, I found that the SS exhibited a 30% loss in force prior to onset of muscle atrophy after acute RTC tear using the rat model. The initial loss of force was associated with a decrease in the size and continuity of the neuromuscular junction (NMJ). The SS muscle was also more susceptible to injury, which was associated with a reduction in collagen packing density. Therefore, SS size is not the strongest predictor of force output with acute RTC tears. In addition, the increased susceptibility to injury could compound the dysfunction already apparent in the SS muscle after RTC tear. In study #3, I found that the rabbit model experienced a 40% loss of force after 6 weeks of RTC tear that persisted at 12 weeks. Using a number of different in vivo and ex vivo imaging approaches I found the degree of fatty infiltration (FI) to be the strongest predictor of muscle force production after RTC tear. Surprisingly, the data suggested that muscle atrophy only explained the loss in force in torn muscles when little to no FI was present. Therefore, FI is a prognostic marker for muscle weakness after RTC tear, and can help clinicians predict the force generating capacity of the SS for surgery and rehabilitation decision-making. Results from both studies found that SS contractile function was significantly impaired after RTC tear, and identified measureable markers beyond muscle atrophy that were associated with the loss in muscle force that may act as potential therapeutic targets to improve functional outcomes after RTC tear.
Breast Cancer Type 1 Susceptibility Protein is a Critical Regulator of Skeletal Muscle Lipid Metabolism
(2013) Jackson, Kathryn Campbell; Spangenburg, Espen E; Kinesiology; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)
This dissertation research consists of three investigations in an effort to determine how circulating estrogens affect skeletal muscle lipid metabolism. Loss of circulating estrogens results in significant increases in visceral fat mass and intramuscular lipids (IMCL). These increases in lipid storage are strongly associated with an elevated risk of developing type 2 diabetes. The first investigation examined how the loss of circulating estrogens alters skeletal muscle metabolic function. Ovariectomy (OVX) resulted in significantly higher visceral fat mass and fatty acid sarcolemmal transporter content, which corresponded with elevated IMCL. Skeletal muscle in the OVX group exhibited lower acyl carnitine species suggesting impaired lipid flux through the mitochondria. Lastly, mitochondrial oxygen consumption rates were impaired in OVX skeletal muscle fibers. The results from this study gave rise to a search to identify an estrogen- sensitive mechanism that regulated lipid transport into the mitochondria. Study two determined for the first time that the BRCA1 protein, which is encoded by an estrogen-sensitive gene, is present and functions as an integral regulator of lipid metabolism in skeletal muscle. Specifically, BRCA1 binds to acetyl CoA carboxylase in response to acute exercise. The in vitro induction of decreases in BRCA1 expression resulted in higher IMCL content, reduced mitochondrial oxygen consumption rates, and elevated reactive oxygen species production. Surprisingly, no differences in BRCA1 content were detected between males and females. In the final study, an inducible, skeletal-muscle specific, BRCA1 KO mouse was developed. Ablation of BRCA1 in skeletal muscle resulted in exercise intolerance and the development of kyphosis. Contrary to our hypothesis, loss of functional BRCA1 in skeletal muscle attenuated the negative metabolic consequences of chronic high fat diet exposure. Collectively, these data provide strong rationale that BRCA1 is an important regulator of skeletal muscle metabolic function and further provide evidence that BRCA1 function is critical in multiple tissues across the body.
The Browning of the All Blacks: Pacific Peoples, Rugby, and the Cultural Politics of Identity in New Zealand
(2008-05-07) Grainger, Andrew David; Andrews, David L; Kinesiology; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)
In this dissertation I examine how the complex, and often contradictory, discourses of being a 'Pacific person' are played out in, and through, New Zealand rugby. In particular, I interrogate how these discourses--manifest in various forms of public expression--structure, regulate, and, potentially, challenge traditional notions of nationality. In the opening chapters I first explore how liberal values and the goals of inclusion and pluralism have been an important part of defining New Zealand identity. In this regard Pacific peoples are playing an ever-more important role. I suggest, however, that an emergent 'Pacific multiculturalism' actually reinforces white cultural power. It also masks the way national belonging has been racialized in New Zealand, and the role rugby has, and continues to, play in inscribing the Otherness of Pacific peoples. What I suggest is needed is alternative or resistant models of 'culture.' In the concluding chapters I turn to the notion of diaspora as one potential alternative. Rearticulating the insightful ideas of Paul Gilroy in my penultimate chapter, I argue that diaspora can be productively adapted as a model to comprehend the lives, travels, migrations, and significances of Pacific athletes. I suggest they provide important diasporic resources for rearticulating modes of belonging that exceed national boundaries. Methodologically, this project is a discursive analysis of the public discourses of Pacificness circulating in a diverse range of documentary, literary, and media sources. I suggest that this critical analysis of the performance, practice, and institutions of Pacific/New Zealand rugby provides a unique context within which to examine the ensemble of discourses and forces by which identity is understood and produced, and through which the Pacific subject in constituted. My hope is that, in accord with Gilroy (1993), this analysis both identifies and actively produces alternatives to divisive discourses of national and ethnic absolutism. That is, my goal is to produce a text which not only critiques, but offers strategies of resistance to, the practices, structures, and ideologies of exclusion.
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.
Cardiac Mitochondrial Function and Exertional Tolerance in a Rat Model of Pressure-Overload Induced Heart Failure
(2022) Li, Harry Zichen; Kuzmiak-Glancy, Sarah; Kinesiology; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)
Heart failure (HF) is characterized by the inability of the heart to provide adequate cardiac output to meet their body’s demand for fuel and oxygen, particularly during periods of exertion. In fact, a hallmark characteristic of HF is exertional intolerance where performing activities brings about, or exacerbates, symptoms of dyspnea and/or fatigue. This exercise intolerance has been attributed to altered cardiac and skeletal muscle function. The myocardium of the heart is reliant upon cardiac mitochondria to generate sufficient ATP to fuel this highly metabolically active tissue. Therefore, reduced mitochondrial ATP production may play a role in myocardial dysfunction and contribute to reduced cardiac output in HF. Mitochondria react to intracellular signals to respond to energetic demands, and therefore, mitochondrial function is a product of both the mitochondria itself and the environment in which it resides. Intracellular Ca2+ and Na+ are of particular interest as they play a role in regulating mitochondrial function and the intracellular concentrations are elevated in ventricular myocytes in HF. Therefore, a goal of these investigations was to evaluate how altered Na+ and Ca2+ can impact the ability of cardiac mitochondria to respond to an increase in demand in mitochondria isolated from young healthy rat hearts, as well as rats with pressure-overload induced HF. A second goal of these investigations was to determine if pressure-overload induced heart failure altered exercise capacity, as well as in vivo and ex vivo skeletal muscle strength. In the first study, mitochondria were isolated from the ventricular tissue of young, healthy male rats, and oxygen consumption and mitochondrial activation by Ca2+ was assessed in the presence of elevated Na+ to mimic the cellular environment of HF. Ca2+ effectively activated mitochondrial ATP production, despite elevated Na+, suggesting that the ionic conditions of HF ventricular myocytes alone are not sufficient to disrupt mitochondrial function. In the second study, mitochondrial function was assessed under the same ionic conditions as the previous study, however, mitochondria were isolated from male rats with pressure-overload induced hypertrophy or sham-operated controls. Ca2+ was able to activate mitochondrial function regardless of Na+ concentration in both HF and sham mitochondria; however, failing mitochondria exhibited depolarized mitochondrial membrane values across these respiration rates, implicating an impaired potential for ATP production in failing ventricular mitochondria. In the third study, HF and sham male and female rats were evaluated for their exertional tolerance, and the results indicated that HF rats tolerated treadmill running and showed no deficits in grip exercise; however, solei muscle from female heart failure rats exhibited diminished contractile capacity, suggesting female skeletal muscle may respond differently than male skeletal muscle to heart failure. These findings indicate that failing mitochondria may be intrinsically dysfunctional regardless of an altered ionic environment and that there may be sexual dimorphism in the skeletal muscle function and its role in exercise intolerance in HF.