Statistical analysis
Statistical analyses were performed using the SPSS 20.0 software package (version 20.0; IBM, New York, US). The Shapiro–Wilk test was used to verify the distribution of data. Descriptive statistics were expressed as mean ± standard deviation. A repeated measures ANOVA was used to verify the differences within each group. Between-group differences were assessed using analysis of covariance (ANCOVA) with the baseline score included as the covariate. The statistical significance was set at 