Table 1 Eligibility of the participants

Inclusion criteria

   - 18 to 60 years of age

   - permanent or long-term employment (30 hours or more per week)

   - no sick leave or other absence exceeding two weeks during the preceding month

   - not more than 30 days on sick leave due to any health problem during three preceding months

   - employee is not listed for any surgery that requires more than one week of sickness absence

   - no plan for longer absence from work during 12 months after enrollment

   - an employee can be enrolled only once

General exclusion criteria

   - acute infections

   - major accidental injury

   - active inflammatory arthritis

   - suspected occupational injury or disease

   - malignant tumour diagnosed or treated during the preceding year

   - severe mental disorder

   - pregnancy

   - severe pain (> 7 on a scale from 0 to 10)

   - pain interferes with sleep severely (> 7 on scale from 0 to 10)

Pain area specific exclusion criteria

   Back region:

   - muscle weakness in the lower extremities related to back pain

   - positive straight-leg-raising test

   - pain-related trunk list

   - painful spasm of the back when bending forward

   Neck and shoulder region:

   - muscle weakness in the upper extremities related to the pain

   - head compression or movements induce radiating pain below elbow level

   - painful torticollis

   Shoulder and upper extremity regions:

   - muscle weakness related to the pain

   - severe pain in movements interfering with most functions

   Lower extremities:

   - pain prevents walking