MyalgiaMuscle FatigueFatigueMuscle, SkeletalMusclesPainMuscle ContractionMuscle ProteinsMuscle Fibers, SkeletalMuscle, SmoothElectromyographyMuscle, Smooth, VascularIsometric ContractionMuscle DevelopmentQuadriceps MuscleRespiratory MusclesFatigue Syndrome, ChronicMental FatigueAbdominal MusclesPhysical EnduranceNeck MusclesMuscle WeaknessMuscle Fibers, Fast-TwitchMuscle RelaxationMuscle DenervationMuscle Fibers, Slow-TwitchElectric StimulationTorqueMyocytes, Smooth MuscleMitochondria, MuscleExerciseIntercostal MusclesBackOculomotor MusclesDiaphragmMuscle, StriatedMuscle SpindlesTime FactorsPhysical ExertionPapillary MusclesMuscular DiseasesMuscle StrengthBiomechanical PhenomenaMuscle CellsMasseter MuscleElbowFacial MusclesMasticatory MusclesLactic AcidMotor NeuronsMuscular AtrophySatellite Cells, Skeletal MuscleExercise ToleranceCalciumOxygen ConsumptionLegGlycogenPectoralis MusclesBicyclingExercise TestElectric Stimulation TherapyPhosphocreatineRunningInhalationFemoral NerveLumbosacral RegionKneePsoas MusclesAdaptation, PhysiologicalLocomotionHindlimbMyographyMyofibrilsHand StrengthTemporal MuscleRabbitsProprioceptionSarcoplasmic ReticulumRats, WistarMovementWeight-BearingCells, CulturedAnalysis of VarianceAnkle JointMyosin Heavy ChainsPharyngeal MusclesLower ExtremityRegional Blood FlowSpectroscopy, Near-InfraredEnergy MetabolismNeuromuscular JunctionAgingIsotonic ContractionModels, BiologicalAdenosine TriphosphatePostural BalanceAction PotentialsRats, Sprague-DawleySignal Processing, Computer-AssistedHelium