Electronic Thesis and Dissertation Repository


Master of Science




Dr. Marsh


Previous research suggests that estrogen exhibits a protective effect on skeletal muscle and may help curb the effects of induced damage. Eccentric (ECC) exercise has been shown to provide the greatest levels of exercise induced muscle damage (EIMD) and with indirect markers of muscle damage including decreases in strength, increased inflammation, and higher magnitudes of delayed onset muscle soreness (DOMS). Studies have shown that elevations of the T2 relaxation times of activated muscles coincide with these other indirect measures of muscle damage. The purpose of this study was to compare the effects of a high intensity ECC elbow flexor exercise in both a group of males and females on T2 relaxation time and coinciding indirect measures of muscle damage to determine if sex provided any differences in results. No significant differences were found in T2 times within or between groups in the 3 regions of interest except for the brachialis measures in the female group (81.9% increase) and average measures of the male group (38.6% increase) from baseline to 72 hours post protocol. These findings coincided with no significant relative differences in cross-sectional area (CSA) (14.5%; 32.6%), strength (-33.6%; -15.2%), or pain measures in males and females respectively from baseline to 72 hours post protocol. The main finding of this study was that following high intensity ECC exercise, estrogen did not provide evidence of a protective effect on skeletal muscle. T2 relaxation time may not be an adequate direct measure of muscle damage. The size of the groups in this study, especially the females, could potentially have resulted in low statistical power therefore affecting the significance of the results.