Discussion
The results of this study will enhance our knowledge on the efficacy of combining the interferential current with the modified Pilates exercises in participants with chronic low back pain. The existing literature on the use of Pilates exercises have shown significant effects in reducing pain and disability. However, these effects were only maintained in the short-term [47]. The same results were observed with interferential current, which apparently is more effective than placebo when combined with other therapies [48] in reducing pain. This effect was also only maintained in the short-term. Therefore, it is assumed that the combination of these two techniques could facilitate the participant’s ability to perform the exercises more efficiently, resulting in a significant clinical improvement that could be maintained in the medium-term. Thus, the results of this randomized controlled trial will help physical therapists in the process of clinical decision-making.
The present study will be conducted with a satisfactory sample size to detect a significant clinical effect of treatment with a low risk of bias, since it was designed to obtain a score of eight on the PEDro scale. Another feature of the study is its pragmatism since the Pilates exercises will be individualized and will respect the condition of the participants. The exercises will follow a handout created by researchers with approximately 130 exercises divided into levels of progression (Additional file 1), which increases the clinical relevance of the results.
Limitations of this study are related primarily to the inability to blind the therapists and participants of the study. The therapists applying the interferential current must be aware to the type of electrotherapy used. In addition, to minimize bias and therapist interference, the therapists conducting the Pilates exercise session will be blinded to the electrotherapy intervention. Since the participants are involved in the Pilates exercise, they may not be entirely blind. However, participants will be unaware of which group of electrotherapy they were allocated and will be asked to refrain from talking to each other and from talking about the resources used in the treatment. The evaluator and the therapists responsible for the Pilates method will be aware of the allocation only after data analysis.
We are currently at the stage of data collection. A total of 116 participants have been evaluated at baseline, 90 participants have been evaluated immediately after treatment (6-week follow-up after randomization) and 30 participants have been assessed at the 6-month follow-up after randomization. Up to this time, five losses were recorded at the 6-week follow-up and two losses in the 6-month follow-up. Publication of the results and release of the spreadsheet with the data encoded is expected to occur during the first semester of 2015.