Muscle ContractionElectromyographyVolitionMuscle, SkeletalIsometric ContractionMuscle CrampMuscle FatigueMusclesHandwritingMuscle, SmoothEvoked Potentials, MotorRectus AbdominisTorqueElectric StimulationMotor CortexHandMotor NeuronsMuscle ProteinsMuscle, Smooth, VascularMuscle Fibers, SkeletalVoluntary ProgramsUterine ContractionMuscle DevelopmentMuscle RelaxationMyocardial ContractionCalciumMuscle Fibers, Fast-TwitchMuscle SpindlesMuscle Fibers, Slow-TwitchRabbitsMyocytes, Smooth MuscleTracheaMuscle DenervationGuinea PigsBiomechanical PhenomenaMuscle, StriatedMitochondria, MuscleTime FactorsNeck MusclesQuadriceps MuscleVasoconstrictionRespiratory MusclesPapillary MusclesMuscle WeaknessPhysical ExertionIsotonic ContractionOculomotor MusclesMovementMyofibrilsMyosinsAbdominal MusclesHindlimbPeristalsisPotassium ChlorideMyosin Light ChainsRats, Sprague-DawleyTropomyosinMasticatory MusclesRats, WistarReflexAcetylcholineFacial MusclesActinsElbowDose-Response Relationship, DrugSarcomeresDiaphragmTroponin CMuscle CellsRecruitment, NeurophysiologicalGastrointestinal MotilityNeuromuscular JunctionUrinary BladderCarbacholMuscle TonusReflex, Stretchrho-Associated KinasesModels, BiologicalCatsMasseter MuscleVasoconstrictor AgentsPhysical Conditioning, AnimalExercisePhysical EnduranceH-ReflexDogsLegAdenosine TriphosphateActomyosinPhenylephrineMuscular DiseasesPsoas MusclesTroponinIleumNorepinephrineCells, CulturedAction PotentialsCaffeineMyographyIntercostal Muscles