PhosphocreatineMagnetic Resonance SpectroscopyCreatineAdenosine TriphosphateEnergy MetabolismPhosphatesPhosphorus IsotopesCreatine KinasePhosphorusMuscle, SkeletalCreatine Kinase, BB FormAdenosine DiphosphateLactatesCreatine Kinase, MM FormLactic AcidOxygen ConsumptionCreatine Kinase, Mitochondrial FormHydrogen-Ion ConcentrationOxidative PhosphorylationGlycolysisMitochondria, MuscleMusclesMyocardiumExerciseMuscle ContractionGuanidinoacetate N-MethyltransferaseGlycogenAdenine NucleotidesAspartic AcidHypoxia, BrainBrainMuscle FatigueAdenosine MonophosphateInosine MonophosphateDichloroacetic AcidPhysical ExertionPhosphorus CompoundsErgometryKineticsPerfusionPhysical Conditioning, HumanCholineIodoacetic AcidRats, Inbred StrainsOxygenBrain ChemistryAcetylcarnitineMyocardial ContractionAcidosisGlycerylphosphorylcholineIodoacetatesIsometric ContractionPerhexilineGlucoseHeartPyruvate Dehydrogenase ComplexRestDinitrofluorobenzeneProtonsPyruvic AcidTime FactorsPropionatesMitochondria, HeartLegMagnetic Resonance ImagingPhysical EnduranceAmidinotransferasesPyruvatesAdenylate KinaseAnoxiaBrain IschemiaQuadriceps MuscleRats, Wistar