Effectiveness of a cognitive behavioural intervention on mental health in young footballers: A quasi-experimental study

Table 4 Pre-post changes by group in the Depression Anxiety Stress Scales-21 (Wilcoxon test and Rosenthal’s r), mean ± SD

Subscale	Group	Pre-test	Post-test	Z (Wilcoxon)	P value	r (Rosenthal)
Depression	Control	4.13 ± 3.66	5.78 ± 4.88	-1.701	0.089	-0.30
	Experimental	3.00 ± 2.98	3.46 ± 2.99	0.639	0.523	0.13
Anxiety	Control	5.75 ± 5.05	5.25 ± 4.28	-0.388	0.698	-0.07
	Experimental	2.92 ± 3.24	3.25 ± 3.04	-0.196	0.844	-0.04
Stress	Control	6.50 ± 5.08	6.38 ± 4.93	-0.226	0.821	-0.04
	Experimental	4.58 ± 3.12	3.79 ± 3.89	-1.388	0.165	-0.28

Z: Test statistics of the Wilcoxon signed-rank test (normal approximation); P: Probability value associated with the within-group comparison; Rosenthal’s r: Effect size calculated from Z and n (|10| = small, |30| = medium, |50| = large).