Inclusion Criteria:  ≥ 18 and ≤ 65 years old. Suffering low back pain. In a subacute and chronic phase  Exclusion Criteria:  Non signature of the informed consent Red Flags are risk factors detected in low back pain patients' past medical history and symptomatology and are associated with a higher risk of serious disorders causing low back pain compared to patients without these characteristics. Yellow Flags are psychosocial factors that increase the risk of developing, or perpetuating chronic pain and long-term disability (including) work-loss associated with low back pain. Pregnancy and lactation Serious trauma or back surgery before the study Illness or dysfunction of balance Visual dysfunction. Neurological illness, dysfunction or pain. Inability to stand up and sit without help Inability to read, understand and complete questionnaires, read and understand a brochure, or understand and follow verbal instructions (e.g. Illiteracy, dementia or blindness) or read, understand and use an app