TWT with NIV increase forced expiratory volume on 1s ( FEV1 ; p = 0.036 ) , tidal volume ( Vt ; p = 0.005 ) , minute ventilation ( MV ; p = 0.013 ) , pulmonary rib cage volume ( Vrcp ; p = 0.011 ) , and decrease the abdominal volume ( Vab ; p = 0.013 ) after test .