Muscle FatigueFatigueMuscle, SkeletalMusclesMuscle ContractionElectromyographyIsometric ContractionFatigue Syndrome, ChronicMental FatigueMuscle Fibers, SkeletalQuadriceps MuscleRespiratory MusclesPhysical EnduranceMuscle ProteinsMuscle, SmoothAbdominal MusclesMuscle, Smooth, VascularTorqueBackMuscle DevelopmentExerciseElectric StimulationMuscle WeaknessNeck MusclesMuscle RelaxationMuscle StrengthDiaphragmPhysical ExertionIntercostal MusclesMuscle Fibers, Fast-TwitchMuscle Fibers, Slow-TwitchElbowMuscle DenervationTime FactorsLactic AcidMuscular DiseasesExercise ToleranceBiomechanical PhenomenaMitochondria, MuscleMyocytes, Smooth MuscleOculomotor MusclesBicyclingFemoral NerveElectric Stimulation TherapyMuscle SpindlesExercise TestMotor NeuronsMuscle, StriatedInhalationLumbosacral RegionOxygen ConsumptionMyographyRunningKneeLegPapillary MusclesPhosphocreatineHand StrengthLocomotionProprioceptionGlycogenAdaptation, PhysiologicalIsotonic ContractionCalciumAnkle JointSpectroscopy, Near-InfraredMuscle CellsWeight-BearingLower ExtremityHeliumFacial MusclesMasseter MuscleMusculoskeletal SystemMasticatory MusclesSignal Processing, Computer-AssistedAnalysis of VarianceSarcoplasmic ReticulumMuscular AtrophyMovementPostural BalanceTask Performance and AnalysisUpper ExtremityRespiratory MechanicsSatellite Cells, Skeletal MuscleRegional Blood FlowRespirationPulmonary Disease, Chronic ObstructiveGaitEnergy MetabolismOxygenPectoralis MusclesExercise TherapyRats, WistarAnoxiaMotor CortexPostureSpinal Cord InjuriesIschemiaAdenosine TriphosphatePhosphates