표 2. | Table 2. 유의미한 공기역학 변수의 평균(표준편차) | Mean and SD of significant aerodynamic parameters

Parameter	Mean(SD)			p-value$	Group paired
	PRE	P1	P3
Peak expiratory airflow	4.79 (2.09)	3.64 (1.55)	3.71 (1.37)	0.004**	PRE-P1
Mean pitch	218.20 (28.01)	199.80 (33.67)	202.41 (29.15)	<0.000**	PRE-P3
Expiratory airflow duration	0.76 (0.25)	0.80 (0.27)	0.98 (0.29)	0.001**	PRE-P3
Expiratory volume	0.10 (0.06)	0.12 (0.09)	0.14 (0.07)	0.018*	P1-P3

two-way mixed ANOVA.
p<0.05,
p<0.01.