Skeletal muscle is a highly plastic tissue that constitutes approximately thirty percent of total body mass and adapts rapidly to changing functional demands. Skeletal muscle is not only the generator of force production, but also plays a crucial role in whole body metabolism and energy consumption. In this book, leading experts in the area of exercise biochemistry and molecular biology in skeletal muscle provide an up-to-date view of the molecular basis of various adaptations of skeletal muscle, with emphasis on new biological concepts (muscle stem cells, muscle steroidogenesis, etc). This book deals with the recent intriguing role of heat shock protein (HSP), AMPK and reactive oxygen species (ROS) for muscle morphology, function and metabolism. Discussed also is the molecular mechanism for protein metabolism and therapeutic application for sarcopenia. The deeper understanding of the signal transduction and modification in skeletal muscle will develop new therapeutic strategies for preventing physical disability and increased risk of morbidity/mortality due to the loss of muscle mass.