Abstract

Mitochondrial biogenesis (i.e., the expansion of the mitochondrial reticulum) is one of the most well-established adaptations to exercise training in skeletal muscle. Since the first in vivo demonstration of mitochondrial biogenesis in the early 1960s, advances in molecular biology have provided valuable insight into the cellular and molecular mechanisms that underpin this adaptive response. These mechanisms include the contraction-induced activation of key signalling proteins within skeletal muscle; the activation of transcriptional regulators that promote DNA binding; the coordinated up-regulation of the nuclear- and mitochondrial-encoded genomes; and the subsequent translation, import, and assembly of newly formed proteins into their final destination within the mitochondria. The bulk of this chapter focuses on the impact of exercise on these regulatory mechanisms in skeletal muscle. We then also discuss the importance of exercise variables such as intensity and volume on training-induced changes in mitochondrial content and respiratory function in skeletal muscle, as well as the functional implications of training-induced mitochondrial remodelling for exercise performance.