Inspiratory CapacityExpiratory Reserve VolumeDyspneaLung Volume MeasurementsBronchodilator AgentsPulmonary Disease, Chronic ObstructiveVital CapacityTotal Lung CapacityForced Expiratory VolumeScopolamine DerivativesRespiratory Function TestsFunctional Residual CapacitySpirometryRespiratory MechanicsAlbuterolExercise TolerancePulmonary VentilationTidal VolumeExercise TestPlethysmographyDiaphragmEthanolaminesRespiratory MusclesAdministration, InhalationLungCross-Over StudiesExerciseDouble-Blind Method