For all patients in both intervention groups the same methods are applied for testing out exercises at the start of the treatment, and for grading exercises during the treatment period. A major goal is to grade exercises so that they are performed pain-free or close to pain-free in both intervention groups. The exercises are standardized for both exercise programs, however individualized and graded continuously in relation to the patient's clinical status. All treatments are carried out under the supervision of experienced and skilled physiotherapists.