Browsing by Author "Thomson, Jasmine Sarah"
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- Item[Beta]-hydroxy-[beta]-methylbutyrate (HMB) supplementation of resistance trained men : a thesis presented in partial fulfilment of the requirements for the degree of Masters of Science in Nutritional Science at Massey University(Massey University, 2004) Thomson, Jasmine SarahA randomised double-blind placebo controlled study design was used to investigate the effects of supplementing 34 resistance trained men (RTM) with 3g/d of β-hydroxy-β-methylbutyrate or a cornstarch placebo on strength and body composition over a 9 week supplementation period. At the beginning of the study period, questionnaires were given to each participant. Prior to and following the period of supplementation; anthropometric measurements were taken, including 8 skinfold sites, height, and body weight; body composition was measured using bioelectrical impedance analysis: strength was assessed using 1 repetition maximum (1RM) strength testing on the leg extension, bench press, and preacher curl apparatus; and food intakes were assessed using 3-day dietary records. During the supplementation period, all participants completed the same resistance training programme and physical activity was assessed using training log book records. Prior to the supplementation period, a significant difference was found between the two supplementation groups for initial body mass indices (BMI: HMB 26.2 ± 0.8; Placebo 22.8 ± 0.9, P=0.0I4). There was no significant difference found between the HMB and Placebo supplemented groups for any other baseline anthropometric (P>0.056). or strength measurements (P>0.583). Over the study duration there was no significant difference found in number of training sessions between the two supplemented groups (P>0.056). Following the supplementation period there was no significant change in anthropometric measurements (P>0.095). nor actual strength (P>0.086) over the study duration. However, percent change in leg extension strength increased significantly more for the HMB-supplemented group than the placebo group (LE: HMB 14.7 ± 3.69% Placebo 4.84 ± 2.8%, P=0.04l). During the supplementation period there was a significant difference found between the dietary intakes of some nutrients between the supplementation groups.The HMB group tended to consume a greater percent of energy from carbohydrates, and had a higher maltose intake. The HMB group had a lower percent of energy from fats in the diet, and consumed lower average cholesterol intake than the placebo group (P <0.047). Several study participants failed to meet the recommended dietary intakes for adult New Zealanders of certain nutrients. The average intakes of energy front carbohydrates, intakes of vitamin A, vitamin E, vitamin B6. potassium, magnesium, calcium, and selenium were low for some participants. The conclusion of this study was that there was no beneficial effect of HMB supplementation on body composition in resistance trained humans, however there was a significant increase found in leg extension strength with HMB supplementation in response to resistance exercise over the 9 week supplementation period.
- ItemEffect of leucine-protein high-carbohydrate post-exercise nutrition on subsequent performance and the protein regulated genomic and signalling events governing adaptive remodelling : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Nutritional Science, Massey University, Albany, New Zealand(Massey University, 2010) Thomson, Jasmine Sarah; Thomson, Jasmine SarahRecovery from prolonged endurance exercise requires fuel replenishment and ultrastructure repair to restore cellular homeostasis; and improvement requires adaptive remodelling. Timing nutrient intake to closely follow exercise may be advantageous to recovery and subsequent performance by facilitating the adaptive processes stimulated by exercise. The objective of this research was to firstly determine if leucine-enriched protein feeding after hard training improved subsequent performance, and secondly to explore the candidate means by which protein-rich post-exercise nutrition mediates recovery, primarily transcriptomic and signalling mechanisms. Study 1 Ten male cyclists ingested leucine-enriched protein-carbohydrate (0.1/0.4/1.2/0.2 g∙kg-1∙h-1 leucine/protein/carbohydrate/fat) or isocaloric high-carbohydrate control (0.06/1.6/0.2 g∙kg-1∙h-1) meals following 2-2.5 h high-intensity interval training on 3 consecutive days. Cyclists performed a repeat-sprint performance test 39 h after training, and markers of physiological recovery and mood state were examined. Study 2 Eight male cyclists ingested protein (0.4/1.2/0.2 g∙kg-1∙h-1 protein/carbohydrate/fat) or isocaloric high-carbohydrate control (0.03/1.6/0.2 g∙kg-1∙h-1) beverages following a single 1.75 h high-intensity interval cycling bout. Muscle tissue samples were collected from the vastus lateralis before exercise, 3-h and 48-h post-exercise. The transcriptome response was assessed by Illumina microarray, candidate gene expression by real time RT-PCR; and phospho-protein signalling by Western blot. Leucine-enriched feeding increased mean sprint power by 2.5% (99% confidence limits, ±3.1%; P = 0.013) and reduced overall tiredness during sprints by 13% (90% confidence limits, ±9.2%). Serum creatine kinase was 19% (90% confidence limits, ±18%) lower than control, but difference in lactate dehydrogenase and muscle pain were trivial and unclear. In the second study, protein-carbohydrate feeding led to moderate and very large increases in cell signalling to translation; mTOR, 4E-BP1 and RPS6 phosphorylation by 3-h. Bioinformatics analysis indicates protein ingestion effects the transcriptome response involved in immune/inflammatory processes, tissue development (extracellular matrix, cytoskeletal, and scarcomere remodelling), and metabolism consistent with increased fatty acid oxidation, compared to control. Post-exercise protein and carbohydrate coingestion during a period of hard training enhances subsequent high-intensity endurance performance and may reduce membrane disruption in comparison to high-carbohydrate feeding. Furthermore, the mechanism responsible for protein-nutrition mediated adaptation may be through enhancing protein translation and fine-tuning the gene expression profile induced by exercise.