Clinical Research Directory

Inclusion Criteria: * Men and women aged 16 years or older. * History of non-specific low back pain during the previous three months and/or recurrent or chronic non-specific low back pain. * Limited hamstring flexibility, defined as hamstring tightness with 75 degrees or less of hip flexion with knee extension during the Straight Leg Raise test. * No previous surgery involving the spine or lower limb. * No hamstring stretching exercises performed in the weeks prior to participation. * Ability and willingness to provide informed consent. * Availability to perform both self-administered physiotherapy techniques according to the study protocol. Exclusion Criteria: * Pregnancy or breastfeeding. * History of hamstring muscle or tendon injury during the previous year. * Lumbar or lower-limb neurological deficits. * Lower-limb length discrepancy. * Specific spinal pathology, including tumor, infection, fracture, or inflammatory disease. * History of lumbar disc herniation. * History of whiplash injury. * Any contraindication to physical exercise. * Menstrual pain at the time of assessment or intervention. * Scheduled surgery during the intervention or follow-up period. * History of cardiac disease. * Incomplete or incorrectly completed questionnaires or missing assessment data. * Refusal to complete part or all of the study intervention. * Development of a low back pain episode during the study intervention.