Thesis (MApSc(HumanMovement))--University of South Australia, 2002.

Thesis (M.S. in human nutrition)--Washington State University, August 2009. / Title from PDF title page (viewed on Aug. 12, 2009). "School of Food Science." Includes bibliographical references (p. 73-93).

Thesis (M.A.)--University of North Carolina at Chapel Hill, 2002. / Includes bibliographical references (leaves 28-32).

Thesis (Ph. D.)--University of Connecticut, 2005. / Includes bibliographical references. Also available online (PDF file) by a subscription to the set or by purchasing the individual file.

Thesis (Ph. D.)--University of Connecticut, 2006. / Title on fiche header: Effects of endurance exercise on skeletal muscle protein turnover and intracellular signaling. Includes bibliographical references.

Extreme physical exertion is commonly associated with acute physiological changes in immune variables known to disturb host defences. Likely induced by the production of stress hormones (e.g., cortisol), partaking in ultra-endurance events with accompanying physiological stressors (e.g., environmental extremes, sleep deprivation and compromised hydration and (or) nutritional status) may amplify stress hormone responses and compromise immune status to a greater extent. To date, research investigating the impact of extreme physical exertion (e.g., ultra-marathon events) on physiological variables is extremely limited. More recently, the potential use of probiotics with known immunomodulatory effects may be considered an appropriate nutritional strategy to improve host defences and minimise and (or) prevent sub-clinical or clinically significant outcomes in active populations.

Glycine-arginine-alpha-ketoisocaporic acid calcium (GAKIC) is a product advertised to increase muscular endurance during exercise via metabolic intervention. Purpose: The purpose of this study was to determine the effect of GAKIC ingestion on maximum strength and muscular endurance. Methods: Utilizing a double-blinded, crossover design, participants completed an upper and lower body resistance exercise protocol once using 11.2gs GAKIC, and the other with a placebo. Results: An increase in maximum strength was observed in the 1RM portion of the lower body protocol phase with statistical trends in the lower body TLV portion of testing. No significant differences were found in upper body 1RM, upper body TLV, HR, BLa, and Glucose between conditions. Conclusion: We concluded that in this protocol, GAKIC increased maximum strength in the 1RM leg press exercise. Further research is encouraged in resistance exercise.

Ergogenic L-citrulline and malate are amino acids used in specific combination to effect muscular endurance during athletic performances. Purpose: The study aimed to investigate the ergogenic properties of citrulline-malate (CM) during a resistance training protocol. Methods: Utilizing a randomized, counterbalanced, double blind study, fifteen trained males completed a resistance training protocol once using placebo (PL) and once with CM (8.0g). Results: CM supplementation increased repetitions in chin-ups, reverse chin-ups, push-ups, and total trial repetitions. Blood lactate was significantly increased post-exercise compared to pre-exercise, but was not significantly different between CM and placebo. Further, a significant interaction effect was revealed for systolic blood pressure, a significant condition effect for diastolic blood pressure, and a significant time effect for HR. Post-hoc analysis revealed that SBP responses were more elevated in the placebo condition during recovery. Conclusion: Collectively, these novel findings suggest CM increases muscular endurance during upper body resistance exercise.

<P> The limited strength model of self-regulation describes self-regulation as a limited, consumable, and renewable internal resource that is depleted when people attempt to control their emotions, thoughts or behaviours (Baumeister & colleagues 1994; 1996). Evidence indicates a consistent relationship across emotional, mental, and physical domains that task performance in all of these areas draws on the same limited resource and is governed by processes occurring within the central nervous system (Galliot, et al., 2007). The main purpose of this study was to examine the effects of self-regulation depletion on muscle activity (EMG) and physical stamina via an isometric task (ankle dorsiflexion). A secondary objective was to investigate trait self-control as an effect modifier of cognitive self-regulation depletion effects on physical stamina. It was hypothesized that individuals would show a greater decline in isometric endurance performance after undergoing a self-regulatory depletion manipulation compared to when they were exposed to· a non-depletion task of similar duration. It was also expected that participants would exhibit greater increases in EMG amplitude after being depleted compared to when not depleted. Additionally, it was hypothesized that people who scored lower on a measure of trait self-control would demonstrate greater depletion effects (i.e., greater pre-to-post performance differences) than those who scored higher on trait self-control. The study was a within-subjects cross-over design involving 31 informed and consenting sedentary university students (M^age= 21.72 ± 2.57 years). Participants were stratified by gender and randomized to experience either cognitive depletion (modified Stroop task) or non-depletion (colour word reading task) for their first trial. In each trial, they completed two isometric ankle dorsiflexion endurance trials at 50% of their MVC (predetermined by initial MVC) separated by the cognitive task. Due to an unexpected differential carryover effect of exposure order, analysis of the data was carried out for each testing session, with primary analysis focused on Time 1 as suggested by Grizzle (1965). Time 1 data indicated a trend towards significance (p = .13) for performance declines being greater in the depletion group compared to the non-depletion group, and a small effect size of .27 was detected, which is comparable to findings in other related studies (Bray et al., 2008; Muraven & Shmueli, 2006). No statistically significant differences emerged for muscle activity in the tibialis anterior for the depletion group compared to the non-depletion group. Those individuals who scored lower on trait self-regulation showed a non-significant trend towards greater depletion effects on muscular endurance performance than those who scored higher on trait self-regulation (p = .13; Cohen's d = .32). Results support the limited strength model of self-regulation and the trait self-control as an·individual difference factor affecting self-regulation, but raise questions regarding the role of central fatigue effects on muscular activation following self-regulatory depletion. </p> / Thesis / Master of Science (MSc)

Hamm et al., 2021 reported that voluntary wheel running (R) was complementary to micro-dystrophin gene therapy (GT) in mdx mice, a model of Duchenne muscular dystrophy (DMD). After 21 weeks of running, time to fatigue on a treadmill for the mdxRGT mice was increased 1.8-fold compared to mdxGT mice (no run) and ~5-fold compared to mdx mice (no micro-dystrophin, no run). Fatigue times for mdxRGT were similar to wild type runners (WTR), while mdxGT and WT (no run) were also similar. The diaphragm is an important muscle for endurance exercise. Remarkably, diaphragm power in mdxRGT was depressed compared to mdxGT, suggesting a negative impact of running on GT. To explore mechanisms to explain this decrease, transcriptome profiles for each of the study groups were assessed. RNASeq data revealed differentially expressed genes (DEGs) from groupwise comparisons. Transcripts identified using the Jackson Labs' Gene Expression Database and extensive literature review were organized into a master signaling pathway composed of two sub-pathways: muscle regeneration and fast-slow fiber type shift. Both sub-pathways were hypothesized to explain the improved treadmill performance despite decreased diaphragm power in mdxRGT as potential adaptive mechanisms. Analysis revealed that GT alone (mdxGT) rescued transcriptome expression to WT values in the mdx phenotype more than GT and running combined (mdxRGT). This outcome indicates that, at the 26-week timepoint of sacrifice, the signaling of the transcripts in the muscle regeneration and fast-slow fiber type shift sub-pathways was likely not responsible for the observed improved running performance of mdxRGT compared to mdx. / Master of Science / Muscular dystrophy is a group of diseases characterized by progressive muscle wasting and loss of function. Duchenne muscular dystrophy (DMD) is the most common of these conditions, with an occurrence of 18 per 100,000 live births. The muscles of people with DMD lack a protein called dystrophin, which provides structural integrity for muscle fibers during contraction. This lack of dystrophin leads to muscle deterioration over time, leading to people with DMD typically being wheelchair-bound by ten years of age. Animal models of DMD have been created over time to help study this condition. One such model, the mdx mouse, was used in the study that led to this thesis project. In this study, Hamm et al., 2021, some of these mdx mice were given a micro-dystrophin gene therapy (GT). This GT aimed to deliver a smaller, but still functional version of the missing dystrophin protein to the mice, which has been shown to be beneficial in other studies. This study aimed to measure the effect of this GT when combined with voluntary wheel running. As people with DMD cannot exercise under current clinical guidelines, measuring the response of mdx mice to GT and running combined is an important step in determining the safety of such a treatment in human patients. In the study conducted by Hamm et al., 2021, the mice that received the micro-dystrophin GT and access to running wheels (mdxRGT) performed almost twice as well on a treadmill running test than the mice that received GT alone (mdxGT). Despite this positive result, the mdxRGT mice showed decreased diaphragm power generation compared to mdxGT mice. As the diaphragm is the most important breathing muscle, it is also very important for running performance; therefore, the decreased diaphragm power generation seen in mdxRGT mice is apparently contrary to their improved running performance. To explain this discrepancy, this thesis project examined the diaphragm transcriptome of the different groups in Hamm et al., 2021. The transcriptome is the sum total of messenger ribonucleic acid (mRNA) expressed in a given tissue. Deoxyribonucleic acid, or DNA, is transcribed into mRNA, which is then translated into protein. As such, this thesis project looked at the mRNA expressed in the diaphragm of the mice in the various groups of Hamm et al., 2021, specifically comparing the mdxGT and mdxRGT groups. Important mRNA transcripts, or genes, were identified and assembled into signaling pathways, cascades that highlight how transcripts affect each other and ultimately lead to function once they are translated into their corresponding proteins. Two such signaling pathways were generated based on mechanisms that were thought to contribute to the improved running performance-decreased diaphragm power discrepancy in mdxRGT mice -slow fiber type shifting, and muscle fiber regeneration. The expression of many of the mRNA transcripts in these resulting pathways was closer to the control group in mdxGT compared to mdxRGT. The control group was made up of healthy mice, and as such, their transcript expression level is seen as normal. This outcome of mdxGT having more similar expression to the control group than mdxRGT suggests that the expression of the transcripts included in the two signaling pathways (fast-slow fiber type shift and muscle fiber regeneration) likely did not explain the improved running performance despite decreased diaphragm power in mdxRGT mice. As such, future studies are warranted.