HindlimbMuscle, SkeletalIschemiaForelimbLocomotionNeovascularization, PhysiologicRegional Blood FlowDecerebrate StateMuscular AtrophyWeightlessness SimulationCatsSpinal CordLaser-Doppler FlowmetryAmputation StumpsRats, Sprague-DawleyExtremitiesCollateral CirculationElectromyographyCapillariesBiomechanical PhenomenaSpinal Cord InjuriesMotor NeuronsFemoral ArteryReflexPhysical Conditioning, AnimalElectric StimulationDisease Models, AnimalMuscle ContractionLimb BudsRats, WistarRecovery of FunctionLumbosacral RegionMuscle Fibers, Slow-TwitchTurtlesMuscle Fibers, Fast-TwitchMusclesSciatic NerveAfferent PathwaysMuscle Fibers, SkeletalWeight-BearingGaitTime FactorsMice, Inbred C57BLNeurons, AfferentMotor ActivityImmobilizationMuscular Disorders, AtrophicTarsus, AnimalPerfusionLameness, AnimalSpinocerebellar TractsMyosin Heavy ChainsPhysical ExertionLigationMuscle DenervationWeightlessnessOrgan SizeVascular Endothelial Growth Factor AEfferent PathwaysBlood PressureRunningPhysical StimulationAdaptation, Physiological