Date of Award
Master of Science (MSc)
Stuart Phillips, Martin Gibala
The extent of skeletal muscle hypertrophy in response to resistance training is highly variable in humans. To explain the nature of this variability, we focused on the myogenic stem cell population, the satellite cell (SC) as a potential mediator of hypertrophy. Twenty-three males (aged 18-35yrs) underwent 16wk of progressive, whole body resistance training, resulting in changes of 7.9%±1.6 (range of -1.9 – 24.7%) and 21.0%±4.0 (range of -7.0 to 51.7%) in quadriceps volume and myofibre cross-sectional area (CSA) respectively. The SC response to a single bout of resistance exercise (80% 1RM), resulted in an expansion in type one fibre associated SC (MHCI-SC) content of 43.7%±10.4 24h post-exercise pre-training, that shifted, post-training, to an increase in type two fibre associated SC (MHCII-SC) content of 47.6%±21.2 72h post-exercise. Analysis of individual SC responses revealed a correlation between the relative change in MHCII-SC content between 24-72h pre-training and the percentage increase in quadriceps lean tissue mass assessed by MRI (r=0.663, p=0.001). The proportion of SC co-localized with MSTN decreased progressively in the acute time-course following exercise and correlated with SC expansion between Pre-24h (r=0.563, p=0.012) and Pre-72h (r=0.454, p=0.045) in the pre- and post-training time-courses. In conclusion, the SC response to exercise appears to become more specific with training; while individual capacity to invoke the SC response is predictive of training induced muscular hypertrophy and may be limited by the degree of MSTN co-localization.
Bellamy, Leeann M., "TEMPORAL PATTERN OF TYPE II FIBRE-SPECIFIC SATELLITE CELL EXPANSION TO EXERCISE CORRELATES WITH HUMAN MUSCLE HYPERTROPHY: POTENTIAL ROLE FOR MYOSTATIN" (2012). Open Access Dissertations and Theses. Paper 7234.
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