Cardiovascular DeconditioningHead-Down TiltBed RestHeadPostureDown SyndromeHead and Neck NeoplasmsHead MovementsSyncope, VasovagalFemur HeadSperm HeadSyncopeRotationFemur Head NecrosisHead Injuries, ClosedSupine PositionCraniocerebral TraumaOtolithic MembraneGravity SensingGravitationVestibule, LabyrinthOrientationPelvisDizzinessAccelerationOrthostatic IntoleranceWeightlessness SimulationCarcinoma, Squamous CellHeart RateSemicircular CanalsEye MovementsPelvic BonesHead Protective DevicesPostural Orthostatic Tachycardia SyndromeAutonomic Nervous SystemHumeral HeadNeck MusclesVestibular DiseasesTime FactorsTorsion AbnormalityPediculusBlood PressureVestibular Function Tests