Quadriceps MuscleMusclesMuscle, SkeletalThighAnuraMuscle ContractionMuscle StrengthMuscle FatigueMuscle WeaknessTorqueIsometric ContractionKneeKnee JointFemoral NerveMuscle ProteinsMuscle Strength DynamometerMuscle Fibers, SkeletalElectromyographyRana pipiensElectric Stimulation TherapyPatellaRana temporariaExerciseMuscle, SmoothLegMuscular AtrophyElectric StimulationAnterior Cruciate LigamentBiomechanical PhenomenaKnee InjuriesMuscular DiseasesPatellar LigamentNeuromuscular JunctionMuscle, Smooth, VascularRespiratory MusclesMuscle Fibers, Slow-TwitchJoggingMuscle DevelopmentRanidaeOxygen ConsumptionArtificial OrgansMitochondria, MuscleMuscle DenervationTendonsImmobilizationPhysical EnduranceMyofibrilsOsteoarthritis, KneeTime FactorsPatellofemoral JointRange of Motion, ArticularMyostatinWeight LiftingJoint InstabilityBicyclingMuscle Fibers, Fast-TwitchPhysical ExertionMotor EndplateMotor NeuronsWeight-BearingExercise TestBufo bufoGaitPatellofemoral Pain SyndromeBufo marinusCurareArthroplasty, Replacement, KneePotassium IsotopesExercise TherapyMembrane PotentialsRecovery of FunctionRana esculentaPulmonary Disease, Chronic ObstructiveCardanolidesHindlimbRana ridibundaAbdominal MusclesMyocytes, Smooth MuscleMuscle SpindlesLactic AcidAdaptation, PhysiologicalDiaphragmPotassiumParaplegiaBiopsyTubocurarineMuscle RelaxationHypertrophyNeck MusclesOculomotor MusclesGlycogenSodium IsotopesCalcium IsotopesRegional Blood FlowMuscle, StriatedNeostigminePhosphocreatineAnalysis of VarianceOrgan SizeAction Potentials