Respiratory MusclesVital CapacityRespiratory Function TestsDiaphragmBreathing ExercisesInhalationNeuromuscular DiseasesWork of BreathingTotal Lung CapacityRespiratory MechanicsForced Expiratory VolumeMuscle StrengthSpirometryRespirationPressureHypercapniaMuscle WeaknessMusclesMuscle, SkeletalMaximal Voluntary VentilationLungLung Volume MeasurementsIntercostal MusclesInspiratory CapacityMuscle FatigueMaximal Midexpiratory Flow RateLung Diseases, ObstructiveForced Expiratory Flow RatesMuscle ContractionResidual VolumePulmonary VentilationPulmonary Disease, Chronic ObstructiveDyspneaMaximal Expiratory Flow RateAbdominal MusclesRespiration DisordersPulmonary Diffusing CapacityRespiratory ParalysisMuscle Fibers, SkeletalMuscle ProteinsExercise ToleranceMuscle, SmoothRespiratory InsufficiencyLung DiseasesElectromyographyPeak Expiratory Flow RateFunctional Residual CapacityPhysical EnduranceRespiratory Physiological PhenomenaAirway ObstructionAirway ResistanceMuscle, Smooth, VascularThoraxMuscle DevelopmentMuscular DiseasesTidal VolumeAsthmaExercise TestTime FactorsBronchodilator AgentsMaximal Expiratory Flow-Volume CurvesMuscular Dystrophy, DuchenneRespiratory TherapyOxygen ConsumptionPulmonary Gas ExchangeExerciseRespiration, ArtificialMuscle Fibers, Fast-TwitchQuadriplegiaMuscle Fibers, Slow-TwitchCoughMuscular AtrophyLung Diseases, InterstitialPhrenic NerveSmokingIdiopathic Pulmonary FibrosisCarbon DioxideIsometric ContractionCystic FibrosisQuadriceps MuscleVentilator WeaningBronchitisPhysical ExertionNeck MusclesThoracic WallRespiratory Tract DiseasesReference ValuesExhalationCross-Sectional StudiesAdministration, InhalationDustPulmonary EmphysemaBlood Gas AnalysisOxygenSeverity of Illness IndexMuscle DenervationProspective StudiesMethacholine ChlorideScopolamine DerivativesBronchoconstrictor Agents