Quadratus lumborum stiffness is meaningfully but not simply related to chronic low back pain. A 2025 shear wave elastography study reported that QL stiffness was negatively correlated with pain intensity and central sensitization and positively correlated with physical quality of life. Together with the other clinical variables, stiffness accounted for roughly 49 percent of the variance in chronic low back pain markers.
What did the 2025 quadratus lumborum study actually find?
QL stiffness moved in the opposite direction of pain. A 2025 study in Medicina used shear wave elastography to assess QL stiffness in chronic low back pain patients and found three relationships:
- Higher QL stiffness correlated with lower pain intensity.
- Higher QL stiffness correlated with lower central sensitization scores.
- Higher QL stiffness correlated with higher physical quality of life.
Stiffness, together with pain intensity, physical quality of life, central sensitization, and chronicity, jointly explained about 49% of the variance across these clinical indicators. QL stiffness on its own did not independently explain central sensitization variance, but it improved the overall model fit. The authors suggested that quantifying QL stiffness may help identify early stages of chronic low back pain before more overt musculoskeletal changes become visible.
Why is the stiffness-pain relationship counterintuitive here?
Because stiffness in the QL of a chronic pain patient may reflect tonic stabilization, not the pain generator itself. The QL contributes to lumbar stability and lateral trunk control. Patients with worse pain and worse central sensitization tend to inhibit stabilizers rather than over-recruit them, which would show up as lower measured stiffness on the painful side or globally.
The pattern is consistent with broader literature on stiffness and pain. A 2020 PLOS ONE study found that in chronic neck and back pain patients, the more painful side did not show higher myofascial tissue stiffness than the contralateral side. Stiffness and pain can move independently, in the same direction, or in opposite directions depending on the muscle, the chronicity, and the patient's stabilization strategy.
Survey data: In a 2026 survey of 455 patients who stopped chiropractic care, 58% cited perception-based reasons: 36% felt no progress, and 22% felt better and stopped. Neither group was told their stiffness was still elevated.
What is the clinical takeaway for chiropractors and PTs?
Stiffness is a signal worth measuring, but it should not be interpreted as a direct proxy for pain. The practical use is comparing the patient to themselves over time and looking at side-to-side asymmetry, not benchmarking absolute values against population averages.
| What you observe | What it may suggest | What it does not mean |
|---|---|---|
| QL stiffness higher on painful side | Tonic guarding or compensatory recruitment | That stiffness is causing the pain |
| QL stiffness lower on painful side | Possible inhibition or weakness | That the muscle is relaxed in a healthy sense |
| QL stiffness drops over a care plan with pain improving | Down-regulated guarding alongside symptom change | That stiffness reduction caused the pain change |
| QL stiffness drops with no pain change | Mechanical change with persistent central sensitization | Treatment failure |
Does fascia play a role in QL stiffness and pain?
Yes. Fascia is increasingly recognized as a tissue layer that can be both stiff and painful. A 2025 Frontiers in Pain Research review noted that fascia is richly innervated by nociceptors and that fascial densification, fibrosis, and inflammation may contribute to both tissue stiffness and pain in myofascial pain syndrome. The QL is surrounded by thoracolumbar fascia, which is a known source of nociceptive input in low back pain populations.
A stiffness reading at the QL therefore reflects a composite signal: muscle tonus, fascial state, and connective tissue mechanics. That is one reason absolute stiffness values are difficult to interpret without a within-patient baseline.
What about other lumbar muscles?
The multifidus and lumbar erector spinae have been studied more frequently than the QL, and the findings are broadly similar: measurable but non-linear relationships with pain. A 2024 study in the International Journal of Sports Physical Therapy reported myotonometry reliability in low back pain adults was good to excellent across positions, with ICC values for the lumbar multifidus reaching 0.94 or above. A 2024 reliability study confirmed that handheld myotonometry can reproducibly assess lower lumbar myofascial stiffness in healthy adults, which is the prerequisite for any clinical comparison.
For routine practice, measuring multifidus, erector spinae, and QL at a defined landmark and standardized patient position gives a fuller stabilization profile than any one muscle alone.
How do you measure QL stiffness in practice?
Two methods are validated and clinically reproducible.
Shear wave elastography produces high-resolution stiffness mapping but requires an ultrasound machine with the elastography module and a trained operator. It is the research gold standard and the modality used in the 2025 Medicina study.
Handheld myotonometry produces single-point stiffness readings in N/m at the skin surface. A 2021 study in Diagnostics found that shear wave elastography and the MyotonPRO produced correlated stiffness readings across major muscles, supporting handheld myotonometry as a portable alternative when imaging is not available. The QL is reachable from the lateral abdominal wall with the patient prone or side-lying.
Whichever tool you use, lock down patient position, landmark, and time of day. Lumbar stiffness readings vary with posture, spinal level, and muscle activation state, so reproducibility depends on a written protocol that is followed every visit.
Frequently Asked Questions
How does quadratus lumborum stiffness relate to chronic low back pain?
A 2025 shear wave elastography study found that QL stiffness was negatively correlated with pain intensity and central sensitization and positively correlated with physical quality of life. Together with other clinical variables, it explained roughly 49% of the variance.
Does more QL stiffness mean more pain?
No. The 2025 data showed higher QL stiffness was associated with lower pain scores and better quality of life. Stiffness in this muscle may reflect tonic stabilization rather than a pain generator.
Why is the stiffness-pain relationship not one-to-one?
Pain perception is shaped by central sensitization, fascial nociception, and multisensory integration in the brain. Stiffness reflects local tissue mechanics. A 2020 PLOS ONE study found the more painful side often does not show higher stiffness in chronic populations.
Should clinicians measure QL stiffness routinely?
It is one signal among several. Side-to-side asymmetry and within-patient change over time are more useful than absolute values. Combine with multifidus and erector spinae readings for a fuller stabilization picture.
What if QL stiffness is low in a chronic low back pain patient?
Low QL stiffness may suggest inhibition or reduced tonic activity. In the 2025 data, lower QL stiffness was associated with higher pain and worse physical quality of life. The clinical implication is to evaluate stabilization patterns rather than assume looser equals better.
How is QL stiffness measured clinically?
Shear wave elastography for imaging-grade measurement, or a handheld myotonometer for portable single-point readings. A 2021 Diagnostics study showed the two modalities produce correlated readings, supporting myotonometry as a portable alternative.
Does fascia contribute to the QL stiffness signal?
Likely yes. The QL is surrounded by thoracolumbar fascia, which is richly innervated and can become fibrotic or densified. A 2025 Frontiers in Pain Research review noted that fascia contributes to both stiffness and nociception in myofascial pain syndromes.
One approach is to add a second channel of objective data alongside subjective pain reports. Options include soft tissue stiffness measurement (such as MuscleMap), range-of-motion testing, and posture analysis. Each gives you something concrete to show the patient rather than asking them to take your word for it.