Muscle FatiguePhysical EnduranceFatigueMuscle, SkeletalMuscle ContractionMusclesElectromyographyIsometric ContractionFatigue Syndrome, ChronicMuscle Fibers, SkeletalMental FatigueQuadriceps MuscleRespiratory MusclesExerciseMuscle ProteinsRunningAbdominal MusclesMuscle, SmoothMuscle StrengthBackPhysical ExertionMuscle, Smooth, VascularTorqueBicyclingMuscle WeaknessOxygen ConsumptionElectric StimulationNeck MusclesMuscle DevelopmentExercise ToleranceMuscle RelaxationDiaphragmLactic AcidExercise TestMuscle Fibers, Fast-TwitchPhysical Conditioning, AnimalMitochondria, MuscleTime FactorsElbowMuscle Fibers, Slow-TwitchIntercostal MusclesAdaptation, PhysiologicalPhysical Education and TrainingMuscle DenervationBiomechanical PhenomenaGlycogenAthletesSportsExercise TherapyMuscular DiseasesLegInhalationMyocytes, Smooth MusclePhysical FitnessAthletic PerformanceKneeElectric Stimulation TherapyOculomotor MusclesHand StrengthCitrate (si)-SynthaseEnergy MetabolismFemoral NerveMotor NeuronsMuscle SpindlesMuscle, StriatedLumbosacral RegionIsotonic ContractionLocomotionPhosphocreatineMyographyLower ExtremityAnalysis of VariancePapillary MusclesPulmonary Disease, Chronic ObstructiveRespirationWeight-BearingAnkle JointTask Performance and AnalysisAnaerobic ThresholdPostural BalanceCalciumProprioceptionTrack and FieldOxygenRespiratory MechanicsSpectroscopy, Near-InfraredMuscle CellsMuscular AtrophyAgingCross-Over StudiesRegional Blood FlowRats, WistarResistance TrainingHeliumFacial MusclesSwimmingMasseter MuscleMotor ActivityMusculoskeletal SystemGait