Theses/Dissertations - Health, Human Performance and Recreation

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    Exploring the clinical utility of myotonometry to identify neuromuscular impairments in individuals with low back pain.
    (2023-08) McGowen, Jared M., 1979-; Koppenhaver, Shane.
    Low back pain (LBP) is one of the most reported musculoskeletal disorders amongst adults. Identifying LBP-related impairments with reliable and valid clinical measures is recommended to improve clinical decisions and rehabilitation outcomes. Myotonometry is an objective method to reliably quantify the property of muscle stiffness through portable, handheld devices. Individuals with LBP have demonstrated increased stiffness in lumbar musculature, but this has only been determined under limited conditions (prone and/or relaxed). The aim of these studies was to determine the test-retest reliability of myotonometry in lumbar (lumbar multifidus [LM], longissimus thoracis [LT]) and thigh (vastus lateralis [VL], biceps femoris [BF]) musculature with participants in standing and deadlifting postures. Secondly, a cross-sectional design was used to compare stiffness of the LM, LT, VL, and BF muscles of individuals with and without LBP across standing and deadlifting postures. Intraclass correlation coefficients (ICC3,2) of the stiffness measures were good to excellent in all muscles across the standing position ( ICCs: VL = 0.94 [0.87-0.97], BF = 0.97 [0.93-0.98], LM = 0.96 [0.91-0.98], LT = 0.81 [0.59-0.91], and were excellent in all muscles across the deadlifting position (ICCs: VL = 0.95 [0.89-0.98], BF = 0.94 [0.87-0.97], LM = 0.96 [0.92-0.98], LT = 0.93 [0.86-0.97]). Within the deadlift condition there was a significantly greater increase in the percent-muscle stiffness change that occurred in the VL (p = .029, 21.9%) and BF (p = .024, 11.2%) muscles for the control group. There were no differences in percent-muscle stiffness changes for the standing condition nor were there any absolute muscle stiffness differences between the two groups for the standing or deadlifting conditions. These results may expand the research and clinical applications of myotonometry to identify muscular deficits and track intervention effectiveness. Future studies should seek to expand on these findings by using myotonometry to further investigate the relationships between muscle stiffness and deadlift performance in LBP populations of varying degrees of pain and disability.
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    Cardiovascular disease risk and Covid-19 related PTSD in healthcare workers : the effects of moderate-intensity exercise and curcumin supplementation.
    (2023-08) Walbolt, Jarrett, 1995-; Koh, Yunsuk.
    Post-traumatic stress disorder (PTSD) has been linked to a greater risk of cardiovascular disease and, associatively, poor markers of inflammation, oxidative stress, and endothelial function. Healthcare workers are at greater risk for PTSD development, particularly during pandemics. Curcumin is a bioactive compound sourced from spice turmeric that exhibits anti-inflammatory and antioxidant effects in humans. Chronic moderate-intensity exercise is also known to trigger anti-inflammatory and antioxidant processes. Pathways that are detrimentally affected by PTSD are affected in the opposite direction by both moderate-intensity exercise and curcumin, meaning each may act as an effective way to mitigate cardiovascular risk caused by PTSD. The purpose of this study was to examine the potential effects of moderate-intensity exercise and curcumin on inflammation, oxidative stress, and endothelial function in healthcare workers. Twenty-four healthcare workers were divided in a randomized, double-blind fashion into three treatment groups: curcumin/exercise (CE), curcumin/no exercise (CNE), and placebo/no exercise (PNE). They participated in their given treatment for 6 weeks. Regardless of the treatment, all groups significantly improved the Impact of Event Scale and Hospital Anxiety and Depression Scale (p < 0.05). Improvement in the Cohen Perceived Stress Scale neared but did not reach a statistical significance (p = 0.053). Regardless of the treatment, all groups had an increase in fat mass (p = 0.027). There were no statistically significant changes in the inflammatory markers, including TNF-a, IL-6, and IL-8 or the oxidative stress markers, SOD and GPx (p < 0.05). In conclusion, claims that curcumin, with or without exercise, could improve oxidative stress, inflammation, or PTSD symptomology were not substantiated by this study. This may be due to the specific subject population, healthcare workers, in the current study and uncontrollable factors such as the progression of the COVID-19 pandemic.
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    Exploring the mechanistic underpinnings of cancer-induced cachexia.
    (May 2023) Beaudry, Anna Grace, 1997-; Law, Michelle L.
    Cancer cachexia (CC) is described as a multifactorial syndrome of progressive, unintentional weight loss occurring in 30-90% of advanced cancer patients and 80% of metastatic cancer patients. Despite the major burden CC poses on both patient quality of life and life expectancy, knowledge of this disease is still limited. There is much room for further research, both mechanistic and functional. Specifically, this dissertation will explore: (1) preclinical research reporting and replication standards, (2) sex differences in CC-imposed heart dysfunction, and (3) the influence of obesity on CC.
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    Dehydration in high school girls wrestling.
    (May 2023) Fenton, Jennae McKenzie, 1999-; Leutholtz, Brian C.
    Little data currently exists for the female wrestling population as the sport is ever-growing. This study is to determine the effect of dehydration on mental toughness for high school female wrestlers. Nine athletes, ages 14–17 years old, underwent two measurements of hydration status which took place at the beginning and middle of the season, and one mental toughness questionnaire completed at the end of the season. The athletes were assigned a personal unique identifier, several non-invasive measures were captured to determine hydration, and the standardized MTQ-10 questionnaire was used to determine mental toughness. A negative correlation was found between the mental toughness attributes of feeling worthwhile, coping, and looking on the bright side to the hydration measure of urine color in the mid-season measurements. No other values were deemed statistically significant. The results provide preliminary evidence that hydration status affects mental toughness and additional research is recommended.
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    The anabolic and anti-catabolic effects of long-chain omega-3 polyunsaturated fatty acid supplementation on functional muscular outcomes.
    (August 2022) Heileson, Jeffery L., 1984-; Funderburk, LesLee K.
    Long-chain omega-3 polyunsaturated fatty acids (LC n-3 PUFAs) are associated with multiple benefits, primarily related to cognitive and cardiovascular health. Recently, LC n-3 PUFAs, eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), have received considerable attention from the athletic and military communities for their potential application to physical performance and recovery. While multiple lines of evidence have provided valuable insight into the plausible mechanisms, the influence of LC n-3 PUFAs on functional skeletal muscle outcomes remain elusive. As such, this dissertation will investigate the potential anabolic influence of LC n-3 PUFA supplementation on body composition and strength. Additionally, the differential effects of two bioactive LC n-3 PUFAs, EPA and DHA, on muscle recovery following exercise-induced muscle damage will be explored.
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    Effectiveness of lifetime fitness course activities at improving movement efficiency through Fusionetics movement efficiency test.
    (2022-05-02) Ruckman, Sarah, 1998-; Shim, Jaeho.
    Exercise has lifelong benefits, specifically increased quality of life. University physical activity courses are designed to instruct on fundamental principles of exercise form and specific sports. Yet, in these courses there is a lack of evidence of improving movement efficiency (ME) that may highlight poor movement quality. The main purpose of this study was to determine how effective lifetime fitness (LF) activities at Baylor University are at improving ME. Eleven participants were recruited to perform a Fusionetics movement efficiency test at the beginning, middle, and end of the academic semester. Significance was found in overall ME scores from the pre and the post-test (pre 75.33 ± 6.34, post 70.69 ± 4.96). Within subgroups, a significant decrease was found between tests of the 2-leg squat (pre 78.786 ± 10.883, mid 89.19 ± 6.906) and the 1-leg squat (mid 47.72, post, 27.27). A significant increase was found between left (pre 54.55, mid 75.7) and right (pre 27.28, mid 60.6) hip symmetry. Future research should include a longer testing period to determine the effectiveness of ME testing detecting muscular or movement deficits in a sedentary university population.
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    Intra-rater reliability of rehabilitative ultrasound imaging of the erector spinae and gluteus medius muscles.
    (2021-11-03) Pokhrel, Swikriti, 1995-; Koppenhaver, Shane.
    Rehabilitative ultrasound imaging (RUSI) is an evolving tool which allows non-invasive quantification of muscle function. Currently, RUSI is used primarily in abdominal and lumbar multifidus muscles, and there is a need to expand its use to other clinically relevant muscle groups. The purpose of this study was to examine intra-rater reliability of RUSI measurements of erector spinae (ES) and gluteus medius (GM) muscle thickness at rest and at submaximal contraction in healthy participants. Methods: ES and GM muscles of 30 participants were imaged at rest and submaximal contraction. Intra-rater reliability estimates using a single and average of three measurements were also compared. Results: ICCs for both ES and GM muscle thickness ranged between .89 to .93 for single measures and from .94 - .97 for average measures. Conclusion: This study confirms a high intra-rater reliability of ultrasound measurements of ES and GM muscle thickness when an average of three measures are used.
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    The potential synergistic effect of combined blood flow restriction training and betaine supplementation on skeletal muscle mechanotransduction-associated cell signaling.
    (2021-10-19) Machek, Steven Brian, 1991-; Willoughby, Darryn Scott, 1963-
    Blood flow restriction (BFR) training and betaine supplementation both possibly facilitate myofibril-level mechanotransduction via intracellular cell swelling. Furthermore, the latter may augment the former through osmolyte-associated protein protection and subsequently attenuated fatigue. Therefore, the purpose of this randomized, double-blind, placebo-controlled investigation was to explore a potential extra-to-intracellular fluid flux-mediated BFR-betaine synergy on intramuscular phosphorylated signaling targets. The present investigation also examined the impacts of a possible BFR-betaine synergy and whether it may enhance total resistance load-volume accrued, which would ultimately promote greater metabolic stress and commensurate anabolic hormone concentrations. Erstwhile, a novel narrow-elastic BFR cuff was validated (against a commonly employed wide-rigid device) amongst 20 resistance trained subjects (25±5y) to demonstrate that these products could produce the previously standardized full-venous and partial-arterial occlusion that otherwise mediates BFR-associated adaptation. Eighteen resistance trained men (23±5y) visited the laboratory after supplementing with either 6g/day betaine anhydrous (BET) or equivalently dosed cellulose placebo (PLA) for 14-days. Following supplementation, all participants performed six sets (last two to muscular failure) in further randomized, counterbalanced, and crossover fashion of either high-load (HL; 70% one-repetition maximum [1RM]) or low-load BFR (LL-BFR; 20%1RM) leg press exercise. Participants underwent vastus lateralis muscle biopsies and venipuncture before (PRE) and 30-minutes post (POST30M) exercise to assess phosphorylated focal adhesion kinase (FAKTyr397), insulin receptor substrate 1 (PanTyrIRS1), and ribosomal protein S6 kinase beta-1 (p70S6KThr389), as well as serum hormone (growth hormone and insulin-like growth factor-1 [IGF-1-] levels. All statistical analyses were performed at a significance level of p<.05. Analyses revealed no significant main exercise or supplement effects, nor any interactions for FAKTyr397 or PanTyrIRS1. Furthermore, BFR combined with betaine yielded similarly equivocal main effects and failed to reveal any notable interactions for total load-volume, nor any metabolic or hormonal targets. There was nevertheless significant supplement-specific effects for p70S6KThr389 (p=.030) and IGF-1 (p=.042), whereby BET supplementation yielded higher relative levels versus PLA. Despite lacking evidence for a BFR-betaine synergy, these data further substantiate BFR as a suitable alternative to conventional high-load resistance training, as well as ultimately support betaine’s potential anabolic potential.
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    More than a place to play : evaluation of youth physical literacy at Play Streets.
    (2021-07-29) Bridges Hamilton, Christina Nicole, 1993-; Umstattd Meyer, M. Renée.
    Play Streets are being implemented across the U.S. during the summer months as temporary street closures (recurring or episodic) that for a specified time, create safe, free (i.e., no cost for attendees) opportunities for outdoor play. Despite numerous benefits of physical activity, many youth, especially those from low-income and/or communities of color, fail to meet physical activity guidelines. Physical literacy is a multifaceted conceptualization of knowledge and skills, throughout experiences, required to realize physical activity potentials. Research examining the role of physical literacy in non-school based physical activity settings is lacking. PlayStreets provide one example of a free, safe physical activity opportunity for youth. The purpose of this study was to examine the structural validity of the PLAYself assessment tool and describe perceived physical literacy of youth attendees at an established Play Streets program in Chicago, Illinois (PlayStreets) during 2018. During summer 2018, trained researchers collected intercept survey data at 16 PlayStreets across 11 hosting organizations in Chicago, Illinois. Youth aged 7-17 years attending PlayStreets, with guardian permission and verbal assent, could participate by interview administered survey. Data were analyzed using SPSS v. 27 and AMOS v. 26. The original PLAYself (27-items) model did not provide acceptable fit. Modifications were made to the model using the physical literacy definitions as a guide. The final model resulted in a 11-item, 4-factor model that provided acceptable fit (χ2=40.47, df=37, p=0.32, CFI=0,96, TLI=0.94, GFI=0.91, RMSEA=0.04, SRMR=0.07). The average physical literacy score for youth (n=62) was 69.72 (SD=14.28) = moderate perceived physical literacy. Youth who participated in sports had higher physical literacy, physical competence, and affective psychological scores compared with their non-participating peers (p<0.05). Physical competence scores were also significantly higher for males than females (p<0.05). While this study provides some evidence of the validity of the 11-item modified PLAYself it should be revisited before it continues to be used in the field. Findings contribute valuable information to the limited literature regarding physical literacy in community-based settings. More research is needed to cross-validate the modified scale in larger and diverse samples and determine if Play Streets can facilitate increasing youth’s perceived physical literacy.
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    Exploring adverse outcomes and potential alleviators of burnout in athletic training students.
    (2021-06-25) Vineyard, Ashlyne P., 1993-; Gallucci, Andrew R.
    The primary purpose of this study was to determine if increased burnout scores (i.e., EE, DP, PA) predicted negative academic outcomes (i.e., low GPA, depressive symptoms, thoughts of drop out, unprofessional clinical and cheating behaviors) in athletic training students. A theoretical model predicting the relationships between academic variables (e.g., study time), burnout scores, and adverse outcomes in dental students proposed by Atalayin et al. (2015) was adapted for use in this study. The secondary purpose of this study was to determine if physical wellness behaviors (i.e., diet quality, physical activity) and coping mechanisms related to burnout scores in a sample of athletic training students. This relationship was hypothesized based on previous literature identifying relationships between coping mechanisms and burnout scores in other samples of healthcare professionals and student samples (Cumbe et al., 2017; Guo et al., 2018; Naugle et al., 2013; Palupi & Findyartini et al., 2019). We also sought to determine if coping mechanisms and physical wellness behaviors mediate the relationship between stress and burnout in our sample of athletic training students based on findings identified in other samples of students and healthcare providers (Raedeke & Smith, 2004; Wallace et al., 2010). Path analysis and structural equation modeling were utilized to identify if our adapted model successfully described the relationships between academic variables, burnout scores, and adverse outcomes in our sample of athletic training students. Our model successfully identified that increased study time predicted increased burnout scores in our sample of athletic training students. Additionally, increased burnout scores predicted one or more adverse outcomes of burnout in our sample. Pearson correlation coefficients identified relationships between stress, burnout, physical wellness behaviors, and coping mechanisms. Adaptive coping mechanisms and diet quality were related to reductions in burnout scores on one or more burnout subscales. Furthermore, we identified that diet quality and maladaptive coping mechanisms mediated the relationship between stress and burnout scores on one or more subscales.
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    Obesity-induced alterations to the immunoproteasome : a potential link to impaired proteostasis in skeletal muscle.
    (2021-07-09) Fletcher, Emma A., 1982-; Gordon, Paul M., 1960-
    Effective maintenance of muscle mass is a highly regulated, complex process dependent on a tight balance between muscle protein synthesis and breakdown. Evidence suggests obesity creates a toxic intramuscular environment, which can damage cellular proteins. Such a disruption to proteostasis likely contributes to obese muscle pathology. Although inflammation and/or oxidative stress are considered central to impaired proteostasis, the underlying mechanisms are unclear. Nevertheless, the immunoproteasome (iProt), known to respond to inflammation and oxidative damage, may play a role. The overarching aims of the studies depicted in this body of work were two-fold. The investigation discussed in Chapter Four sought to elucidate whether a high-fat, high-sucrose diet alters intramuscular iProt content and catalytic activity in wild-type mice to identify a possible mechanism for impaired muscle proteostasis in obesity. Total proteasome content and activity, as well as estimates of muscle oxidative damage, inflammation, muscle mass and strength were also assessed. However, the procedure to analyze iProt activity was previously validated on mouse spleen extracts, and the translatability to skeletal muscle was unknown. Consequently, Chapter Three describes a preliminary study to optimize the assay protocol in murine skeletal muscle. The results from Chapter Four demonstrate oxidatively damaged proteins were increased in the muscle of obese mice. These intramuscular alterations also coincided with reduced iProt and total proteasome activity, and reductions in relative muscle mass and strength. Muscle inflammation was unaffected by obesity. Since the proteasome, particularly the iProt, is a prime mediator in the removal of oxidized proteins, our findings suggest proteasome dysfunction could be a key determining event in the loss of intramuscular proteostasis with obesity. As impaired proteostasis diminishes muscle integrity, the inability to contain oxidative protein damage via the proteasome, provides a plausible explanation for the loss of muscle mass and strength noted in the obese mice. Consequently, the results from the study in Chapter Four not only enhance our understanding of proteasome function in obese muscle pathology, but also suggest the proteasome could be a potential therapeutic target to optimize the maintenance of muscle mass and function in obese individuals.
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    Metabolic health, obesity, and chronic kidney disease : findings from the national health and nutrition examination surveys.
    (2021-07-28) Adair, Kathleen E., 1993-; Bowden, Rodney G., 1966-
    Rising rates of metabolic syndrome, obesity, and death from chronic kidney disease (CKD) have prompted further investigation into the association between metabolic syndrome and CKD. The purpose of this study was to report the frequency of metabolic phenotypes, constellations, and clusters as well as their relationship to renal function in a representative sample of individuals in the United States. We utilized a subsample from the 2013-2018 National Health and Nutrition Examination Surveys (NHANES) and complex survey sample weighting techniques to represent non-institutionalized US civilians. Four metabolic phenotypes were identified including metabolically healthy normal weight (MHN), metabolically healthy obese (MHO), metabolically unhealthy normal weight (MUN), and metabolically unhealthy obese (MUO). Renal function as measured by estimated glomerular filtration rate (eGFR) was compared among the phenotypes. Sixteen possible constellations of 3 or more risk factors were classified and four metabolic clusters, which represented MetS with hyperglycemia (Cluster I), MetS with hypertension (Cluster II), MetS with hyperglycemia and hypertension (Cluster III) or MetS with normoglycemia and normotension (Cluster IV), were assessed for renal function and CKD status. The metabolically healthy normal (MUN) phenotype was most frequent in the subsample taken (38.40%). Renal function was lowest in this phenotype in the regression analysis (B= -9.60, p<0.001) and highest in the MHO (B= 2.50, p>0.05) and this persisted with more liberal definitions of metabolic syndrome. Systolic blood pressure had the strongest correlation with overall eGFR (r= -0.25, p<0.001) and individuals with low HDL had higher renal function compared to the overall sample. The constellation with the lowest renal function consisted of hypertension, high triglycerides, and large waist circumference (82.86 ml/min/1.73m2). Cluster III had the highest odds of CKD (OR=2.57, 95%CL=1.79, 3.68) and Clusters II and III had the lowest renal function (87.82 and 87.28 ml/min/1.73m2, respectively). In conclusion, the metabolically unhealthy phenotypes had the lowest renal function regardless of weight status. Metabolic constellations and clusters with hypertension as a risk factor had low renal function. HDL had a small negative correlation with renal function, indicating that more research should be done in this area.
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    Effects of prophylactic lace-up ankle bracing on kinetics of the lower extremity during a state of fatigue.
    (2021-05-01) Alonzo Rocchio, Diana Nicole, 1996-; Shim, Jaeho.
    Prophylactic lace-up ankle braces are worn to prevent ankle sprains during states of fatigue, which may increase GRF and VLR during landings and increase risk of injury. Studies have not examined effects of wearing lace-up ankle braces while fatigued when completing functional sport movements. 15 subjects completed this study throughout two sessions. One session they wore a brace and the other they didn’t. Kinetic data (Fz, Fy, Mz, Mx, VLR) was collected during a cutting task and drop landing both pre and post-fatigue each session. There were significant effects from brace on Fz and Fy (P=.004, P=.014), from fatigue on Fz, Fy, and VLR (P=.001, P=.023, P=.008), and interaction between brace and fatigue on Fz between sessions and comparing R and L during same session (P=<.001, P=.015). Significant interactions between brace and fatigue do not show increases in GRF and VLR, so wearing a brace during fatigue doesn’t seem to put individuals at higher risk for injury. Lace-up ankle braces alone do however increase GRF.
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    The effects of carbon insoles on reactive strength and vertical leg stiffness as an indicator to sprint performance.
    (2021-05-02) Sims, Benjamin Jeffrey, 1993-; Shim, Jaeho.
    Sprinting is the peak expression of performance. Different strength and physical characteristics play roles in the expression speed. Leg stiffness is a major factor on rate of force development, and performance. The pairing of eccentric and concentric contractions is termed the stretch shortening cycle and is assessed by the reactive strength index (RSI). The purpose of this study was: (1) to investigate the effects of the carbon insole on the expression of vertical leg stiffness (kvert) and RSI; (2) examine the effects of the carbon insoles on sprint kinematics. Fifteen participants were recruited and were asked to perform a drop jump and a 20-yard sprint in two conditions (carbon, traditional insoles). The only significant differences between conditions for the performance variables were in the drop jump (p > 0.05). Further research is needed looking at sprint kinetics and kinematics and varying insole stiffness at maximal velocity.
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    Effects of prophylactic lace-up ankle braces on kinetics and kinematics of the lower extremity during a state of fatigue.
    (2021-04-23) Hagan, Austin Michael, 1995-; Shim, Jaeho.
    Prophylactic lace-up braces are commonly used on athletes regardless of ankle injury history to reduce lateral ankle sprains (LAS). However, their ability to limit ankle sagittal range of motion has the potential to alter knee kinematics and is linked to chronic knee pathologies. Thirteen college-aged (6 males) and (7 females) experienced in landing/cutting sports completed a random crossover design study consisting of a 90° cutting task and a 15m beep test fatigue protocol. Braced conditions elicited a significant reduction in ankle sagittal displacement (ASD) in both pre-fatigue (-10.08°) and postfatigue (-9.51°). Also, w/brace increased in time to peak knee flexion pre-fatigue (3.26fps) and post-fatigue (1.74fps) and peak knee flexion pre-fatigue (6.14°) and post fatigue (10.92°). Prophylactic ankle braces limiting ASD appear to alter knee mechanics that are associated with chronic knee pathologies. Clinicians should use other prophylactic measures of hinge ankle braces or prevention programs to reduce LAS.
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    Changes in activation of Mexican-heritage children and father physical activity social networks in response to a father-focused family-centered health program.
    (2021-04-13) Prochnow, Tyler, 1992-; Umstattd Meyer, M. Renée.
    Physical activity (PA) and active play are beneficial for physical, mental, and emotional health; however, very few families meet PA guidelines to attain health benefits. Unfortunately, Latinx children report lower PA levels and are at elevated risk for developing obesity. PA is also significantly associated with PA behaviors of friends and family through support, influence, and co-participation. Past studies have focused on mother’s influence on and perception of child PA, especially within Mexican-heritage families; however, recently scholars have called for a renewed focus on fathers to promote the health of their children. This dissertation examined if participation in a father-focused family-centered health program changes the social connections within Mexican-heritage children’s and fathers’ PA networks. Participating families consisting of child (aged 9-11), mother, and father were recruited from colonias by promotoras for participation in a six-week father-focused family-centered health program focused on family dynamics relative to healthy eating and active living. Children reported up to five people (alters) they actively played with the most in the previous month before and after the program. Likewise, fathers reported up to five people they with whom they were physically active. Children and fathers then reported each alters’ sex, their relationship to the alter, and frequency with which they played with the alter, if they thought the alter was active regularly, and if they alter helped them to be active as well as what they did most often with that person. Multilevel regression models examined the change in alter level variables. Children and fathers were more likely to report more frequent PA with their alters after the program when compared to before the program. Additionally, girls were more likely to report more frequent active play with alters when compared to boys; however, a significant interaction term indicated boys were more likely to increase this frequency as compared to girls. Supporting families to activate their social network ties to be more active, which is theoretically supported through family systems theory and Social Ecological Model, could result in more PA for children and families. Results indicate these connections or activations are possible through a family-centered father-focused health program.
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    Effects of resistance exercise load on androgen receptor–DNA binding, androgen regulated gene expression, and β-catenin mediation in human skeletal muscle.
    (2020-07-17) Cardaci, Thomas D., 1994-; Willoughby, Darryn Scott, 1963-
    The purpose of the study was to determine the effect low (LL) and high (HL) load resistance exercise on serum total and free testosterone, and muscle testosterone, dihydrotestosterone (DHT), androgen receptor (AR), and AR-DNA binding, β-catenin, and AR-regulated/responsive gene expression. Ten participants completed LL and HL resistance exercise with samples collected pre-, 3h post-, and 24h post-exercise. Separate 2x3 factorial repeated measures ANOVAs were completed. Serum free and total testosterone significantly decreased 3h post-exercise with free testosterone remaining significantly decreased 24h post-exercise in both conditions (p<.05). No significant differences were observed in muscle AR, testosterone, or DHT in either condition (p >.05). In response to HL, AR-DNA binding significantly increased at 3h post-exercise (p<.05), whereas no significant differences were observed in response to LL (p>.05). Muscle β-catenin content was significantly greater in HL condition (p<.05). No significant/practical differences were observed in AR, MyoD, MYOG, IGF-1Ea, or p21-cip1 expression (p>.05).
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    Stages of change in dietetics practice.
    (2020-07-16) Beretich, Kaitlan Nicole, 1992-; Funderburk, LesLee K.
    Registered dietitian nutritionists (RDNs) have provided nutrition counseling to patients and clients across practice settings for over 60 years. A major component of a RDNs work includes conducting nutrition assessments and providing nutrition interventions. RDNs must assess the “readiness” or stages of change for all patients and clients to provide appropriate interventions. The Transtheoretical Model (TTM), an integrative model of behavior change, uses stages of change to integrate the processes and principles of change across major theories of psychotherapy. At the core of the TTM is the stages of change construct, which suggests individuals change behaviors over time through a series of stages. While assessing stages of change and the provision of a stage-matched intervention in nutrition counseling is important, there is limited research surrounding the stages of change construct in dietetics practice. Thus, the purpose of this project is to first determine the extent to which RDNs are assessing stages of change in dietetics practice and how this assessment is being conducted, and then develop and validate a staging algorithm for healthy eating in the general population. Chapter Three is a descriptive study of nutrition professionals’ knowledge and use of the stages of change construct in dietetics practice. Chapter Four is a criterion validity study for the dietary stages of change algorithm. Results from the descriptive study revealed most nutrition professionals are familiar with the stages of change construct and are assessing stages of change. However, the methods differed, with the majority using open-ended questions during the patient interview. Assessing stages of change is appropriate and feasible in most practice settings, with low utility in acute care settings and pediatric populations. Results of the criterion validity study revealed a non-linear relationship between stages of change and total healthy eating index (HEI) scores. Mean total HEI-2015 scores were highest among those in precontemplation, suggesting the algorithm misclassified some individuals. However, mean total HEI-2015 scores increased linearly from contemplation to maintenance. These findings are promising and warrant further validity testing to refine this tool for clinical practice.
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    An investigation of acute exercise and FGF21.
    (2020-07-14) Peterson, Matthew, 1992-; Funderburk, LesLee K.
    Fibroblast growth factor 21 (FGF21) is a molecule that freely circulates in the blood and helps to regulate metabolism. Interest in FGF21 stems from its ability to promote weight loss and ameliorate type II diabetes in animal models. Recent findings have shown that blood levels of FGF21 increase after a single bout of aerobic exercise. Neither the mechanism behind this post-exercise increase in FGF21 nor the potential downstream effects of this increase are known. Similarly, little is known about the effect of biological sex or other types of exercise on circulating levels of FGF21. This dissertation will investigate the effects of two different types of exercise – steady state aerobic and sprint interval – on blood levels of FGF21 in healthy males and females. Related to this aim, the dissertation will also investigate the relationship between potential upstream promoters of FGF21 production and circulating levels of FGF21 as well as the potential downstream effects that arise from a post-exercise increase in FGF21. A secondary aim is to investigate the relationship between baseline levels of FGF21 and physiological and lifestyle factors.
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    Effects of blood flow restriction resistance training on strength, vascular and motor function in persons with Parkinson's disease.
    (2020-04-22) Bane, Annie Allison, 1984-; Willoughby, Darryn Scott, 1963-
    Parkinson’s disease (PD) is a neurodegenerative disease that displays itself most notably through motor symptom disruptions. The first line of defense for persons with Parkinson’s disease (PwP) is carbidopa-levodopa (levodopa). While this drug therapy effectively treats motor symptoms, the deleterious effects to the vessels can lead to increased homocysteine, endothelial dysfunction, poor peripheral circulation, restless leg syndrome, autonomic dysfunction and cardiovascular disease. Homocysteine has been identified as a cardiovascular disease risk factor and has been associated with cognitive dysfunction. Resistance exercise is effective at lowering homocysteine and improving motor symptoms of PD. Resistance exercise, however, may cause increased arterial stiffness due to the increased hemodynamic load it causes and may not be complementary for the vessels of older individuals with present arterial stiffness. Blood flow restriction (BFR) resistance exercise has been shown to improve vascular function in healthy, older individuals. The effects of low-intensity BFR (LIRT-BFR) on the vascular and motor symptoms of PD has not been studied. Therefore, the purpose of this study was to determine if LIRT- BFR attenuates or improves endothelial function and homocysteine levels in PwP compared to high-intensity resistance exercise. Thirty-eight PwP on levodopa therapy were assigned LIRT-BFR, high-intensity resistance training (HIRT) or to a control group (CNTRL). The LIRT-BFR and HIRT groups participated in exercise three days per week for four weeks and the CNTRL group was asked to continue their normal routine. Hemodynamic loads and strength improvements were similar between the two exercise groups. There were significant improvements in homocysteine and endothelial nitric oxide synthase (eNOS) for LIRT-BFR and HIRT. Reactive hyperemia index (RHI), peripheral circulation and resting blood pressure only improved for LIRTBFR. HIRT showed worsening RHI, autonomic symptoms and resting blood pressure values. LIRT-BFR significantly improved vascular function in our participants with decreased endothelial function and circulation. This is the first intervention proposed to help attenuate the disruptive vascular effects of levodopa. More research is needed, however, to understand if these effects are lasting and will continue with LIRT-BFR intervention.