Date of Award

2010

Document Type

Thesis

Publisher

Edith Cowan University

Degree Name

Bachelor of Science Honours

School

School of Exercise, Biomedical and Health Sciences

Faculty

Faculty of Computing, Health and Science

First Supervisor

Anthony Blazevich

Abstract

The post exercise inflammatory response is a key signalling mechanism regulating muscle protein synthesis. The purpose of this research was firstly to determine whether muscle mass in non-strength trained individuals was associated with the inflammatory muscle gene response after a single bout of eccentric muscle loading. Secondly, to determine whether changes in muscle cross-sectional area after a chronic increase in muscle loading (resistance training) is related to the inflammatory gene response to a single bout of muscle loading. Eleven male participants (21.6 ± 4.1 years) volunteered for this study. Each participant completed a preliminary testing session that consisted of two triggered muscle biopsies, one immediately before and a second, one hour after a leg extensor resistance exercise bout, including the exercises leg press and leg extension. Eight weeks comprising 3 sets of 10 to 12 reps per set of training followed, where by all participants completed training at moderate intensity (MR; 70% 1 RM) or high intensity (HR; 90% 1 RM). The relationship between GSA, measured using GT scans of the subjects and gene expression of IL-6 and IL-8 were correlated. It was found that the change in IL-6 gene expression and pre-training GSA were related (r=.61, p (one tailed) < 0.05), as were change in IL-8 expression and pre-training GSA were correlated (r=.85, p (one tailed) < 0.05). For the MR group post-exercise IL-6 and IL-8 expression were correlated with pre-training GSA (r=.93, p (one tailed) < 0.05 and r=.90, p (one tailed) < 0.05, respectively). For the HR group neither the change in IL-6 nor IL-8 expression correlated with pre-training GSA or any change in GSA. Individuals with the largest initial muscle mass prior to resistance training had the largest inflammatory response to training. However, there was no relationship between the change in GSA and change in gene expression. Only those in the MR group with the largest initial muscle mass showed a large inflammatory response to the exercise. However they did not increase muscle mass the most after the training period. The present research shows that those with a larger muscle mass have a greater inflammatory response to an exercise bout. However, those that have large increases in gene expression over the course of a single exercise bout do not necessarily show a greater increase in muscle mass over the course of a period of strength training.

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