Effects of Different Exercise Programs Plus Photobiomodulation on Non-specific Low-back Pain.

The purpose of this study will be to investigate the effects of two different exercise programs (Pilates and multicomponent) combined with photobiomodulation therapy (PBMT) on pain intensity, postural balance, and psychological aspects in individuals with chronic non-specific low back pain (CNLBP). Participants will be randomized into four groups (n = 20 per group): Pilates exercise program + active PBMT (PIL+PBMT), Pilates exercise program + sham PBMT (PIL+SHAM), multicomponent exercise program + active PBMT (EX+PBMT) and multicomponent exercise program + sham PBMT (EX+SHAM). The PIL+PBMT and PIL+SHAM groups will be submitted to a supervised 8-wk mat Pilates exercise program (2 x/week) and will receive their respective PBMT (active or sham) on the lumbar region (between L1 and L5) 10 min before and after exercise sessions (totaling 20 min), through a device containing 264 LEDs (132 red and 132 infrared. The EX+PBMT and EX+SHAM groups will be submitted to a supervised 8-wk multicomponent exercise program (3 x/week) and will receive their respective PBMT (active or sham) on the lumbar region (between L1 and L5) imediately before each workout, through a device containing 200 LEDs (100 red and 100 infrared). The sham PBMT will be applied with the device turned off. Participants and the two physiotherapists responsible for the assessments and exercise sessions will be blinded to PBMT treatments. The following variables will be assessed at pre and post-training: anthropometric measures, peak pain intensity, postural balance, perceived disability (Oswestry Disability Index [ODI], Roland Morris disability questionnaire [RMDQ]), kinesiophobia (Tampa Scale of kinesiophobia [TSK]), and Pain-related fear of movement (Pain Catastrophizing Scale [PCS]), and Fear Avoidance Beliefs Questionnaire [FABQ]. Statistical analyses were performed using IBM SPSS Statistics for Windows (version 24.0; IBM Corp., Armonk, New York). The baseline characteristics will be analyzed using an unpaired Student's t test. Nonparametric tests will be used due to ordinal data of the dependent variables (pain intensity, ODI, RMDQ, TSK, PCS, and FABQ-Phys). The Wilcoxon signed-rank test will be used to assess within-group changes (from pre-intervention to postintervention), while the Mann-Whitney U test will be used to compare the between-groups changes (relative difference, ∆% = [post - pre]/pre*100) for all dependents variables. The significance level will set at p < 0.05. The effect size (r) for within- and between-groups changes will be considered trivial (0.0-<0.1), small (0.1-<0.3), moderate (0.3-<0.5), and large (≥0.5).

Inclusion criteria

• Men and women aged 18-75 years
• Self-report of recurrent (≥ 3 x/week) or continuous episodes of nonspecific low back pain for at least 3 months, comprising the lumbar region between L1-L5

Exclusion criteria

• To present a history of musculoskeletal disorders that could affect muscle function
• To make use of medicines that could affect muscle function.
• To present low back pain of specific etiology, such as: tumor, herniated disc, facet syndrome, canal stenosis, among others.
• To have used ergogenic supplements and anabolic steroids for at least six months before study
• To present severe skin diseases in the lumbar region, such as: erysipelas, eczema, dermatitis, psoriasis and urticaria
• To have restrictions for exercises practice considering Physical Activity Readiness Questionnaire (PAR-Q) responses.