Inclusion Criteria:  adults over 18 years of age, lumbar pain and/or referred pain above or below the gluteal fold , with intensity > 3/10, persisting for > 6 months and presenting during the day > 50% of the time.  Exclusion Criteria:  history of serious spinal or lower extremity injury or surgery in the last year identifiable back pain or known pathology known rheumatological condition oral or injectable corticosteroids in the lumbar spine within the last 3 months psychiatric disorder pregnancy manual treatment of the lumbo-sacral region 1 month prior to the experimentation and during the week of the study