This section develops and applies non-invasive methods for the study and definition of alterations in metabolic fluxes and energy status in animals and human subjects using the methods of nuclear magnetic resonance imaging and spectroscopy, near-infrared spectroscopy plus measurement of key proteins and metabolites altered in animal models of disease and in human patients.  It determines the alteration of metabolic efficiency resulting from changes in energy substrate provision to human and animal subjects under a variety of conditions including extreme physical stress, hypoxia, heart failure, cardiomyopathy and myo and neurodystrophic conditions.