Muscle FatigueFatigueMuscle, SkeletalMusclesMuscle ContractionCell HypoxiaIsometric ContractionMuscle ProteinsElectromyographyFatigue Syndrome, ChronicMuscle Fibers, SkeletalMyocardiumAnoxiaMental FatigueHeartMyocytes, CardiacQuadriceps MuscleMuscle, SmoothPhysical EnduranceRespiratory MusclesAbdominal MusclesMuscle, Smooth, VascularPapillary MusclesMuscle DevelopmentMyocardial ContractionElectric StimulationTime FactorsTorqueBackExerciseCalciumMuscle RelaxationMuscle WeaknessNeck MusclesMuscle StrengthCardiac OutputDiaphragmPhysical ExertionOxygenMuscle Fibers, Fast-TwitchMyofibrilsMuscle Fibers, Slow-TwitchSarcomeresIntercostal MusclesOxygen ConsumptionHypoxia, BrainMuscular DiseasesSarcoplasmic ReticulumLactic AcidHeart VentriclesBiomechanical PhenomenaArrhythmias, CardiacElbowRabbitsMitochondria, MuscleMuscle DenervationMyocytes, Smooth MuscleExercise ToleranceCells, CulturedTroponin CRats, WistarRats, Sprague-DawleyCardiac Surgical ProceduresExercise TestFetal HypoxiaMuscle CellsTroponinCardiomegalyAdaptation, PhysiologicalDeath, Sudden, CardiacTroponin IBicyclingPhosphocreatineOculomotor MusclesAction PotentialsInhalationFemoral NerveRNA, MessengerRespirationElectric Stimulation TherapyCardiac MyosinsGlycogenHypoxia-Inducible Factor 1, alpha SubunitMyosin Heavy ChainsMotor NeuronsMuscle, StriatedDogsAdenosine TriphosphateAnalysis of VarianceMuscle SpindlesSarcolemmaRunningLumbosacral RegionEnergy MetabolismMyographyLegCardiomyopathiesModels, BiologicalHeart RateRyanodine Receptor Calcium Release Channel