Muscle FatigueFatigueMuscle, SkeletalMusclesMuscle ContractionCell HypoxiaIsometric ContractionElectromyographyMuscle ProteinsFatigue Syndrome, ChronicMuscle Fibers, SkeletalMyocardiumAnoxiaMental FatigueHeartMyocytes, CardiacQuadriceps MuscleMuscle, SmoothPhysical EnduranceRespiratory MusclesAbdominal MusclesGenetic VariationMuscle, Smooth, VascularPapillary MusclesTime FactorsMuscle DevelopmentMyocardial ContractionElectric StimulationTorqueBackExerciseCalciumMuscle RelaxationMuscle WeaknessNeck MusclesCardiac OutputMuscle StrengthDiaphragmPhysical ExertionOxygenMuscle Fibers, Fast-TwitchMyofibrilsMuscle Fibers, Slow-TwitchSarcomeresIntercostal MusclesOxygen ConsumptionHypoxia, BrainMuscular DiseasesBiomechanical PhenomenaSarcoplasmic ReticulumHeart VentriclesLactic AcidArrhythmias, CardiacRabbitsElbowMitochondria, MuscleMuscle DenervationMyocytes, Smooth MuscleCells, CulturedExercise ToleranceRats, WistarRats, Sprague-DawleyAdaptation, PhysiologicalTroponin CCardiac Surgical ProceduresExercise TestFetal HypoxiaMuscle CellsCardiomegalyTroponinDeath, Sudden, CardiacAnalysis of VarianceRNA, MessengerTroponin IBicyclingModels, BiologicalPhosphocreatineMolecular Sequence DataAction PotentialsRespirationInhalationOculomotor MusclesDogsFemoral NerveMotor NeuronsGlycogenMyosin Heavy ChainsElectric Stimulation TherapyCardiac MyosinsHypoxia-Inducible Factor 1, alpha SubunitAdenosine TriphosphateEnergy MetabolismMuscle, StriatedRunningMuscle SpindlesSarcolemmaHeart RateLumbosacral RegionAgingLeg