This is a randomized and blind clinical trial, whose objective is to evaluate the effects of transcranial stimulation by direct current associated with exercises based on the pilates method on the performance of patients with chronic low back pain.

Considered a public health problem, low back pain is globally presented as a symptomatology of high prevalence, incidence and recurrence. In addition, it is responsible for a large part of disabilities, reduced functional performance, absences from work and impaired quality of life, which brings biopsychosocial impacts to the affected subjects. Treatments that relieve the symptoms of these patients are of great importance to improve the quality of life of these individuals. Thus, this study aims to evaluate the effects of transcranial direct current stimulation associated with Pilates based exercise on chronic low back pain. This is a randomized clinical trial that will be composed of women between 18 and 65 years of age, with a history of low back pain for more than 12 weeks and a minimum pain intensity equal to 3 cm on the numerical pain scale. The volunteers will be randomized into two distinct groups: stimulation + exercise group (EG - will perform a Pilates based exercise protocol combined with transcranial direct current stimulation) and sham stimulation + exercise group (SG - will perform the same exercise program combined with sham stimulation). The interventions, regardless of the group, will be carried out three times a week for four weeks. Participants will be submitted to three assessments: the first (T0) will be performed before the treatment protocols; the second (T1) will be performed after the four weeks of intervention; and the third (T2) will be a follow-up one month after the end of the treatment protocol. Pain sensation, performance, pressure pain threshold, use will be evaluated. For the statistical analysis, a mixed model ANOVA will be performed for the inter and intragroup comparison, with Tukey's post hoc, considering a significance level of 5%.

Inclusion Criteria:

Women with chronic nonspecific low back pain (for more than 12 weeks) and minimum pain intensity of 3 on numerical pain rating scale

Exclusion Criteria:

• diagnosis of fracture and spine pathologies, fibromyalgia, spine surgery in the last year;
• low cognitive level assessed by the Mini Mental State Examination;
• presence of central neurological diseases (such as Parkinson's and stroke) or psychiatric (such as depression or schizophrenia);
• history of epileptic illness;
• seizure history;
• brain implants;
• pacemaker;
• pregnancy