Cost Effectiveness and Effectiveness of the Addition of Different Weekly Frequency of Modified Pilates Method Exercises to a Minimal Intervention in the Treatment of Chronic Nonspecific Low Back Pain: A Randomized Controlled Trial

Low back pain is a major cause of disability and absenteeism and the supervised exercise is a recommended treatment by the guidelines and has been cost-effective. Currently, the Pilates method has shown to be effective in improving pain and disability in patients with chronic low back pain (CLBP). However, there is still no evidence about the ideal number of sessions for the treatment and the interval between sessions to achieve better efficacy of this method for these patients. Thus, the aim of this study is to investigate the effectiveness of the Pilates method with different weekly frequency of sessions in the treatment of patients with nonspecific CLBP. Investigators will assess 296 patients of both genders, with nonspecific CLBP lasting more than three months and aged between 18 and 80 years. Participants will be randomly divided into four groups (n = 74 patients per group): Control Group will receive an educational booklet and no additional exercise, Pilates 1 Group will receive a program of exercises based on Pilates method once a week for six weeks, Pilates 2 Group will receive the same program of exercises twice a week for six weeks and Pilates 3 Group will receive the same program of exercises three times a week for six weeks. The outcomes overall disability (Roland Morris Disability questionnaire), specific disability (Patient-Specific Functional scale), kinesiophobia (Tampa scale for kinesiophobia), pain intensity (Pain Numerical Rating scale) and global perceived effect (Global Perceived Effect scale) will be assessed by a blinded assessor before, six weeks, six and 12 months after randomization. Investigators expect that the largest number of weekly sessions of Pilates method may influence the results in all analyzes (short, medium and long term), since there is a relationship between frequency of exercises and effect size of the treatment.