The stay active concept was the basic management strategy in all study groups. Treatment was individual, in groups or both. Treatment modalities were chosen from a group-specific 'toolbox' after clinical assessment of the patients and according to need. Two orthopedic surgeons at Visby Hospital and eight physiotherapists treated the reference patients. In accordance with the study design, muscle stretching was a treatment option in 51% of the reference group, 41% actually received muscle stretching. Two GPs and nine physiotherapists treated the experimental patients. They received the full reference treatment, plus specific mobilization, spinal manipulation, and auto-traction when indicated. Steroid injections were a treatment option in 52% of the experimental group, 36% actually received injections.