Muscle FatigueMuscle ContractionFatigueMuscle, SkeletalMusclesIsometric ContractionMuscle, SmoothMuscle Fibers, SkeletalMuscle ProteinsElectromyographyMuscle, Smooth, VascularQuadriceps MuscleElectric StimulationMuscle DevelopmentRespiratory MusclesMuscle RelaxationFatigue Syndrome, ChronicAbdominal MusclesMental FatiguePhysical EnduranceMuscle Fibers, Fast-TwitchNeck MusclesTorqueMuscle Fibers, Slow-TwitchMuscle WeaknessCalciumMuscle DenervationMyocytes, Smooth MuscleExerciseMuscle SpindlesMitochondria, MuscleDiaphragmTime FactorsPhysical ExertionIntercostal MusclesBiomechanical PhenomenaMuscle, StriatedBackMyocardial ContractionOculomotor MusclesMuscle StrengthUterine ContractionPapillary MusclesMotor NeuronsRabbitsMuscular DiseasesElbowIsotonic ContractionMuscle CellsFacial MusclesMyofibrilsTracheaMyographyGuinea PigsMasticatory MusclesLactic AcidHindlimbRats, WistarMasseter MuscleLegOxygen ConsumptionGlycogenPhosphocreatineVasoconstrictionRats, Sprague-DawleyMuscular AtrophyActinsKneeSarcoplasmic ReticulumAdenosine TriphosphatePsoas MusclesElectric Stimulation TherapySarcomeresModels, BiologicalMovementLocomotionTropomyosinFemoral NerveNeuromuscular JunctionSatellite Cells, Skeletal MuscleHand StrengthRegional Blood FlowDose-Response Relationship, DrugExercise ToleranceAdaptation, PhysiologicalPotassium ChlorideAcetylcholineCells, CulturedLumbosacral RegionPectoralis MusclesPeristalsisExercise TestBicyclingAction PotentialsAnalysis of VariancePotassiumMyosinsMyosin Heavy ChainsEnergy MetabolismWeight-Bearing