Statistics
Statistical analysis was performed using SPSS ver. 23 [To evaluate changes over time for each variable, the repeated measures analysis of variance tests (ANOVA) with Bonferroni posthoc was performed separately for each group. The effect size was estimated using the value Partial Eta Squared (η2). Values of η2 = 0.01 indicate a small effect; η2 = 0.06 indicates a medium effect; η2 = 0.14 indicates a large effect.In case of statistically significant change during the treatment in the experimental group, these changes have been compared with the same period (between time T1 and time T2) in the control group using the Analysis of Covariance (ANCOVA) test with time T1 values as a covariate. The effect size was also calculated using η2.