Five-step Model of Exercise-induced Muscle Hypertrophy: Contribution of Satellite Cells

Satellite cells are undifferentiated skeletal muscle stem cells lying at the periphery of muscle fiber. The role of satellite cells is now being much appreciated, not only as crucial players during growth and regeneration, but also as mediators in exercise-induced skeletal muscle hypertrophy. This enlargement of muscle mass mainly results from resistance training which initiates five steps of cellular mechanism: signals to synthesis protein, alteration of skeletal muscle growth factor expression and/ or release, regulation of gene transcription, activation of mTOR signaling pathways and finally increased satellite cell proliferation and differentiation. Thus, activated satellite cells are crucial contributors of hypertrophied muscle by providing additional nuclei.