2.5. Statistical Analysis
SD
The statistical analysis was performed using IBM SPSS v.20.0. Descriptive statistics were calculated for all variables. Frequencies were calculated for qualitative variables. Quantitative variables and their differences were expressed as mean and standard de-viation (SD). Prior to the use of the parametric test, the normality assumption was eval-uated using the Shapiro–Wilk test. Levene’s test was used to test for homogeneity of variances between groups. The two-way ANOVA was used to compare between-group and within-group changes over the three measurement periods. This model was performed for each dependent variable where the FR group or PNF group was the between-subjects factor and time was the within-subjects factor. If the assumption of sphericity was violated, the Greenhouse–Geisser correction was utilized for interpretation. When a statistically significant effect was noted, a post-hoc analysis was performed, and the Bonferroni correction was used to adjust for multiple comparisons. Effect sizes (ES) were calculated using Cohen’s d coefficient [