Effects of Laser Therapy and Exercise in Participants With Chronic Low Back Pain

Inclusion Criteria: * Patients with non-specific chronic LBP, defined as pain or discomfort between the costal margins and inferior gluteal folds with or without referred pain to the lower limbs; * Persistent LBP for at least 3 months; * Low back pain of intensity reported 3 or higher by the Visual Analogue Scale (VAS), at least once in the previous 7 days; * Aged between 18 and 65 years; * Both genders. Exclusion Criteria: * Patients with severe skin diseases (eg, skin cancer, erysipelas, severe eczema, severe dermatitis, severe psoriasis and severe hives lupus); * Participants with known or suspected serious spinal pathology (e.g., fractures, tumors, inflammatory, rheumatologic disorders, or infective diseases of the spine); * Nerve root compromise; * History of previous spinal surgery (even in a segment other than the lumbar spine) or scheduled surgery; * Pain due to or associated with pregnancy or structural deformity (for example, scoliosis); * Pregnancy; * Comorbid health conditions that could prevent active participation in the exercise programs such as high blood pressure, pregnancy, or cardio-respiratory illnesses; * Having answered "yes" to any of the questions in the Physical Activity Readiness Questionnaire (PAR-Q); * Be treated with PBMT; * Being under physiotherapeutic treatment or perform physical exercise; * Who are using NSAID or start it during the trial; * Who have inability to tolerate the proposed experimental procedures (such as tests of mobility and strength of the lumbar muscles).