Data analysis
disability, pain
The statistical package SPSS IBM version 21 was used for data analysis. Analysis included descriptive statistics. Normality was checked with Kolmogorov–Smirnov. An intention-to-treat analysis was performed using a repeated measures ANOVA. If the assumptions of homoscedasticity and equality of variance were met, we included the baseline variables that presented differences between groups as covariates. If not met, nonparametric analysis of variance (Kruskal–Wallis test) for between-group comparisons at the three evaluation times for the pain, disability, QOL, flexibility and posture variables was included. Between-group differences for each measure were explored using either Student’s The analysis of the data of the qualitative study began with manual transcriptions of the interviews. Names were coded with initials and the consecutive number of the interview to protect the identity of the participants.The formulation of meanings was developed, beginning with the reading of each transcript several times. This process was carried out by the principal investigator and four final year physiotherapy students. After reading the first interview, a meeting was established to create the initial codes. Each researcher coded an additional interview to validate the interpretation which was evaluated in another group meeting. The codebook for data analysis was created using the emergent codes from an interview. Similar codes were grouped into categories that were continuously refined and organized. After axial coding, the relationship between the categories was sought, thus establishing the subcategories. Only those that approached the identified central category were considered. The software used for the qualitative analysis was ATLAS.ti.Integration of the results of the RCT and the qualitative study was developed in a comparative way based on the data; the results are shown in the integration process combining each variable with the categories emerged by interviews [