Metabolic adaptations to marathon training and racing.

During the past 30 years, considerable progress has been made in our understanding of the cellular and molecular factors regulating fuel metabolism during exercise. In particular, advancements in the fields of exercise biochemistry and cell signalling have helped elucidate the mechanism(s) by which perturbations in energy status are monitored inside contracting muscle cells, and have helped identify target molecules that increase fuel supply to maintain adenosine triphosphate concentration. In this brief commentary, we summarise some of the major cellular and molecular adaptations in human skeletal muscle resulting from the intense endurance training required to run a marathon.