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Exercise Science Commons

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Full-Text Articles in Exercise Science

Role Of Fat Content On The Structure And Function Of Human Skeletal Muscle, Joseph A. Gordon Iii Aug 2023

Role Of Fat Content On The Structure And Function Of Human Skeletal Muscle, Joseph A. Gordon Iii

Doctoral Dissertations

Muscle size does not fully explain variations in muscle strength. Fat content has been implicated in muscle weakness, though this relationship remains unclear. The relationship between fat and strength may vary between scales (e.g., cellular, organ, and organism). The goal of this dissertation was to clarify the role of fat in the structure and function of muscle using in vitro and in vivo techniques across multiple scales in adults 21-45 years old. Study 1 tested the agreement of intramyocellular lipid (IMCL) content between oil red o (ORO) and magnetic resonance spectroscopy (MRS) techniques. These measures of IMCL were also compared …


Bioenergetic Mechanisms Of Age-Related Differences In Muscle Fatigue, Liam F. Fitzgerald Mar 2020

Bioenergetic Mechanisms Of Age-Related Differences In Muscle Fatigue, Liam F. Fitzgerald

Doctoral Dissertations

Muscle fatigue is defined as the reduced capacity to produce torque or power in response to contractile activity. Previous work has observed greater fatigue in older than young adults in response to high-velocity contractions, but similar fatigue with age in response to moderate-velocity contractions. The mechanisms for these age-related differences is not clear. One potential explanation is a greater accumulation of putative agents of fatigue (e.g., Pi, H2PO4-, and H+) in older than young muscle during high- but not moderate-velocity contractions. Older muscle may accumulate these metabolites to greater extent because of deficits …


Mechanisms That Limit Oxidative Phosphorylation During High-Intensity Muscle Contractions In Vivo, Miles F. Bartlett Oct 2019

Mechanisms That Limit Oxidative Phosphorylation During High-Intensity Muscle Contractions In Vivo, Miles F. Bartlett

Doctoral Dissertations

Skeletal muscle oxidative capacity plays a critical role in human health and disease. Although current models of oxidative phosphorylation sufficiently describe skeletal muscle energetics during moderate-intensity contractions, much is still unknown about the mechanisms that control and limit oxidative phosphorylation during high-intensity contractions. In particular, the oxygen cost of force generation is augmented during exercise at workloads above the lactate threshold. Presently, it is unclear whether this augmentation in muscle oxygen consumption is driven by increased rates of oxidative ATP synthesis (ATPOX) or by decreases in the efficiency of ATPOX due to mitochondrial uncoupling. To address this …


Changes In Muscle Control And Coordination In Novel Task Learning, Sangsoo Park Mar 2019

Changes In Muscle Control And Coordination In Novel Task Learning, Sangsoo Park

Doctoral Dissertations

Learning many daily life motor skills is critical for survival and the quality of living in humans. As children, we develop walking and running patterns to move the body from point A to B without falling, and we learn to grasp a wide variety of objects during activities of daily living. Motor skills can be properly performed by appropriate muscle activations which are controlled by the central nervous system. How does the central nervous system develop and fine-tune its control strategy to learn a new motor skill? The aim of this dissertation was to better understand how human participants alter …


Cardiovascular Disease Risk And Menopause: Effects Of Cardiorespiratory Fitness, Exercise, And Follicle Stimulating Hormone, Corinna Serviente Nov 2018

Cardiovascular Disease Risk And Menopause: Effects Of Cardiorespiratory Fitness, Exercise, And Follicle Stimulating Hormone, Corinna Serviente

Doctoral Dissertations

Menopause is associated with adverse changes in cardiovascular disease risk factors. A reduction in estrogens is most commonly associated with changing cardiovascular disease risk; however, recent observations suggest that the increase in follicle stimulating hormone that accompanies menopause may also influence risk, potentially through its influence on lipid levels. The changes in cardiovascular disease risk factors may adversely affect endothelial cell function, a pre-clinical marker for cardiovascular disease. Whether cardiorespiratory fitness is protective of endothelial health in this population, thereby mitigating the changes in risk that accompany menopause, is unclear. This dissertation evaluated differences in endothelial health and endothelial responses …


Observing The Molecular Basis Of Thin Filament Activation With A Three Bead Laser Trap Assay, Thomas Longyear Mar 2018

Observing The Molecular Basis Of Thin Filament Activation With A Three Bead Laser Trap Assay, Thomas Longyear

Doctoral Dissertations

Muscle contracts after calcium (Ca++) is released into the muscle cell, resulting from a cascade of events which result in myosin, the molecular motor of muscle, to produce force and motion. Myosin cyclically binds to a regulated thin filament, using the chemical energy of ATP to produce force and motion. Perturbations in muscle, such as a build-up of metabolic by-products or point mutations in key contractile proteins, can inhibit these functions in both skeletal and cardiac muscle either acutely or chronically. Despite the many years we have studied skeletal and cardiac muscle, we still do not have a clear picture …


A Comprehensive Validation Of Activity Trackers For Estimating Physical Activity And Sedentary Behavior In Free-Living Settings, Albert R. Mendoza Nov 2017

A Comprehensive Validation Of Activity Trackers For Estimating Physical Activity And Sedentary Behavior In Free-Living Settings, Albert R. Mendoza

Doctoral Dissertations

The aim of study one of this dissertation was to compare consumer activity trackers (ATs) with the research-grade ActiGraph™ GT3X-BT accelerometer (AG) in estimating energy expenditure (EE) and steps during orbital shaking at different frequencies. To address this aim, we utilized an electronic orbital shaking protocol (twenty-four, 3-minute trials; 2-hour trials). For all comparisons, the AG served as the reference measure. In the 3-min protocol, we showed that on average, the NL-1000 pedometer (NL) produced the lowest error (-9 steps/3-min) at 0.9 Hz (corresponding to moderate intensity). The magnitude of the error for the NL was 14 steps/3-min at a …


Interfacing Continuous Measurement Of Glucose And Physical Activity To Predict Glycemic Control In Individuals With Type 2 Diabetes, Jennifer Blankenship Mar 2017

Interfacing Continuous Measurement Of Glucose And Physical Activity To Predict Glycemic Control In Individuals With Type 2 Diabetes, Jennifer Blankenship

Doctoral Dissertations

Physical activity is a cornerstone in the management of hyperglycemia and risk of cardiovascular disease in type 2 diabetes (T2D). However, the dose response relationship between physical activity and glucose regulation is not well defined. The overall goal of this dissertation was to assess the magnitude and timing of changes of daily glucose concentrations in response to continuous and intermittent light physical activity in T2D. Through utilizing continuous glucose monitors (CGM) and physical activity monitoring concurrently, we were able to assess the glycemic impact of physical activity and sedentary behavior in the free-living environment. Study 1 aimed to examine the …


Feasibility Of A Combined Physical Activity And Sleep Education Intervention For Girls Living In A Low Socioeconomic Status Urban Community, Cory J. Greever Jul 2016

Feasibility Of A Combined Physical Activity And Sleep Education Intervention For Girls Living In A Low Socioeconomic Status Urban Community, Cory J. Greever

Doctoral Dissertations

Declining sleep duration and poor sleep quality is a public health epidemic disproportionately effecting elementary age girls living in low socioeconomic status urban communities. The Girls Dancing and Sleeping for Health (Girls DASH) program was designed to test the feasibility, acceptability, and efficacy of a combined physical activity and sleep education program in this population. In combination with baseline data from a previously conducted intervention in elementary age urban girls living in a low SES community in Springfield, MA, results from a cross-sectional analysis indicated that greater screen time was positively associated with parental reports of child’s sleep quality. Additionally, …


Molecular Mechanisms Underlying The Contralateral Repeated Bout Effect (Crbe) In Human Skeletal Muscle, Ling Xin Aug 2015

Molecular Mechanisms Underlying The Contralateral Repeated Bout Effect (Crbe) In Human Skeletal Muscle, Ling Xin

Doctoral Dissertations

Eccentric (muscle lengthening) exercise induces temporary muscle damage that can lead to long-term muscle adaptation, a process known as the repeated bout effect where subsequent exercise results in less damage. The existence of a contralateral repeated bout effect (CRBE) has been controversial. The primary goals of this study were to: 1) validate the existence of the CRBE; and 2) define the underlying molecular mechanisms. Thirty-six young men performed 100 maximal eccentric actions of the knee extensors using one leg (bout 1) and repeated the exercise with the contralateral leg five weeks later (bout 2). Vastus lateralis muscle biopsies were …


The Role Of The Extracellular Matrix In Mediating Muscle Soreness, Karen L. Riska Mar 2015

The Role Of The Extracellular Matrix In Mediating Muscle Soreness, Karen L. Riska

Doctoral Dissertations

The goal of this dissertation was to examine the role of the extracellular matrix (ECM) in muscle soreness. Study 1 examined how the disruption of the ECM from a minor surgery (e.g. muscle biopsy) affected muscle soreness. Study 1 showed that soreness levels increased at 24 h post-biopsy compared to baseline and resolved within 96 h. However, the level of muscle soreness at 24 h post-biopsy (20 mm) was lower than that reported for performing a strenuous and naïve exercise (40–80 mm). These results will help review boards at institutions where muscle biopsies are performed understand how a muscle biopsy …