Visit 3 after 6 months Clinical examination: Functional assessment of the back. Manual balance test, muscle strength of the back extensors, grip strength with JAMAR, pain drawing, back pain measured by VAS-scale and Borg CR-10, EQ-5D, SF-36, Qualeffo-41. Spirometry. Weight and height. Assessment of spinal curvature. Report of falls since 3 month visit. Use of drugs and analgesics. Blood sample for substance P, IL-6 and CGRP analysis (Calcitonin Gene Related Peptide).