Skeletal muscle hypertrophy and response to training

Abstract

Skeletal muscle of adult mammals retains remarkable plasticity. Hypertrophy is evoked by resistance exercise through increased satellite cell activity and activation of the phosphoinositide 3-kinase pathways involving insulin-like growth factor signaling. Skeletal muscle undergoes fast-to-slow fiber type transformation along with enhanced mitochondrial biogenesis and angiogenesis following endurance exercise. Activation of the Ca2+/calmodulin- dependent kinase and phosphatase signaling pathways and exercise-induced expression of peroxisome proliferator-activated receptor-γ coactivatorlαt play important roles in neuromuscular activity-dependent induction and maintenance of slow muscle gene expression. © 2006 Humana Press Inc.