Isometric Stability vs. Isotonic Mobility for Chronic LBP

Inclusion Criteria: * Age between 18 and 60 years; * Diagnosis of non-specific CLBP, defined as pain localized between the lower rib margin and the gluteal folds persisting for more than three months; * Self-reported pain intensity score between 40 mm and 80 mm on a 100-mm Visual Analogue Scale (VAS), indicating moderate to severe pain; * Pain experienced on at least three days in the month preceding enrollment, with documented interference in daily activities; * A formal referral for physiotherapy management. Exclusion Criteria: * The presence of "red flag" pathologies (e.g., spinal tumor, infection, fracture); - Neurological signs or symptoms suggestive of radiculopathy or myelopathy; * a history of spinal surgery or epidural steroid injections within the previous 12 months; * Systemic inflammatory diseases (e.g., rheumatoid arthritis) or major neurological disorders; * Pregnancy; * Receipt of physiotherapy for low back pain within the last six months; * Current use of non-steroidal anti-inflammatory drugs (NSAIDs) or inability to refrain from their use during the study period; * Any diagnosed psychiatric condition.