Table 1. Comparison of FVC, FEV1, PBU between pre-test and post-test in each group (Mean±SD).

	Category	experimental group	control
FVC (ℓ)	Pre-test	2.72±0.95	1.83±0.74
	Post-test	2.90±0.97*	1.86±0.53
FEV1 (ℓ)	Pre-test	2.42±0.61	1.81±0.70
	Post-test	2.56±0.70*	1.85±0.53
PBU (mmHg)	Pre-test	41.18±1.32	41.64±1.29
	Post-test	44.09±3.08*	41.27±0.90

* p<0.05; FVC, Forced vital capacity; FEV1, Forced expiratory volume in 1 second; PBU, Pressure biofeedback unit