The functions of skeletal muscle, one of the largest organs in the human body, extend well beyond only locomotion. While seldomly the primary cause of disease, healthy and optimally functioning skeletal muscles are essential in preventing various pathophysiological conditions ranging from metabolic to cardiovascular and neurological diseases. Regular physical exercise is one of the cornerstone strategies to prevent or even treat many of these conditions. The molecular mechanisms responsible for these health-promoting adaptations are a complex interplay between countless biological pathways and regulatory networks that are far from completely understood. Rapid technological developments are constantly providing additional insights, while creating more and more layers of complexity. The work described in this thesis is an attempt to further improve our understanding of the homeostatic control of skeletal muscle in relation to exercise adaptations and its rich cell diversity.