PhosphocreatineMagnetic Resonance SpectroscopyCreatineAdenosine TriphosphateEnergy MetabolismPhosphatesPhosphorus IsotopesCreatine KinasePhosphorusMuscle, SkeletalLactatesAdenosine DiphosphateLactic AcidCreatine Kinase, BB FormCreatine Kinase, MM FormGlycolysisHydrogen-Ion ConcentrationOxygen ConsumptionCreatine Kinase, Mitochondrial FormOxidative PhosphorylationMusclesMitochondria, MuscleMyocardiumExerciseMuscle ContractionGuanidinoacetate N-MethyltransferaseAspartic AcidGlycogenAdenine NucleotidesBrainBiotransformationChromatography, High Pressure LiquidKineticsHypoxia, BrainCholineMuscle FatigueAdenosine MonophosphateDichloroacetic AcidRats, Inbred StrainsInosine MonophosphatePerfusionBrain ChemistryOxygenPhosphorus CompoundsPhysical ExertionTime FactorsErgometryGlucoseMetabolomicsGlycerylphosphorylcholinePhysical Conditioning, HumanMetabolomeIodoacetic AcidAcetylcarnitineGas Chromatography-Mass SpectrometryAcidosisMyocardial ContractionProtonsPropionatesPyruvic AcidHeartIodoacetatesPerhexilineIsometric ContractionPyruvatesRats, Sprague-DawleyRats, WistarPyruvate Dehydrogenase ComplexOxidation-ReductionMagnetic Resonance ImagingRestModels, BiologicalMitochondria, HeartDinitrofluorobenzeneAnoxiaLegPhysical EnduranceAmidinotransferasesInositolAdenylate KinaseMass SpectrometryMicrosomes, LiverBrain IschemiaReference ValuesSwineDogsChromatography, LiquidMitochondriaCitric Acid CycleAnaerobiosisQuadriceps MuscleHydroxylation2,4-DinitrophenolMetabolic Clearance RateCytochrome P-450 Enzyme System