Non-specific low back pain is a worldwide health issue that remains poorly understood. Some authors have shown that the thoracolumbar fascia of low back pain adults presents changes in biomechanical properties. As it is richly endowed with pain receptors, the thoracolumbar fascia could therefore be a key contributor to this chronic pain condition. Myofascial techniques (MFTs) are commonly used in manual therapy by practitioners of various backgrounds to address fascia biomechanical properties, but there is a paucity of objective evidence on their effects on tissue state. Musculoskeletal ultrasonography, sonoelastography and myometry are emerging imaging techniques that can quantify the biomechanical properties of fascia and underlying muscle. These innovative techniques could in turn contribute to a better understanding of MFTs effects on fascial properties.

The main objective of this study is to evaluate the immediate effect of a standardized MFT on the elastography features of the lumbar paraspinal muscle and fascia (i.e. myofascial unit). The secondary objectives are to evaluate the immediate effects of a MFT on: i) ultrasonography features of the myofascial unit; ii) myometry features of the myofascial unit; ii) pain intensity.

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