RESUMEN
Chronic nonspecific low back pain (CNLBP) is the most common musculoskeletal condition, which can be influenced by nociceptive, psychosocial, cognitive, and affective aspects, causing vulnerabilities and impairing the individual's ability to manage pain. The association of continuous shortwave diathermy (CSWD) with Pilates-based exercises may contribute to reduce pain, depression, and anxiety in patients with CNLBP. A single-blind randomized clinical trial was performed in which 36 patients with CNLBP were divided into a control group that received placebo CSWD and an intervention group that received active CSWD. Both groups received 12 sessions of Pilates-based exercises. Pain, depression, and anxiety variables were evaluated using the McGill questionnaire, the Beck Depression Inventory, and the Visual Analog Anxiety Scale. Assessments were performed at baseline, after three and six weeks of treatment, and at the three-month follow-up. The Shapiro-Wilk test, Student's t-test, Mann-Whitney U test, chi-squared test, and repeated measures ANOVA, with α=0.05, were used to compare the outcomes, and indicated that active CSWD did not present additional improvement in the assessed variables in CNLBP patients compared to the placebo group. Both groups improved pain and depression at follow-up and reduced anxiety only during Pilates-based exercises. Therefore, only Pilates-based exercises seemed sufficient to manage patients with CNLBP.