In the published myotonometry data, yes. A 2026 case-control study of 31 fibromyalgia patients found significantly higher muscle tone and dynamic stiffness than age-matched controls across three separate muscles. The effect was strongest in the upper trapezius. Elasticity, measured separately, showed no group difference at all.
What did the study find?
Higher tone and stiffness in every muscle tested, with a clear gradient by site. Esen and colleagues, publishing in the European Journal of Applied Physiology in 2026, compared 31 people with fibromyalgia against 31 age-matched healthy controls. They measured the upper trapezius, extensor carpi radialis brevis, and medial gastrocnemius with a handheld myotonometer, alongside pressure pain thresholds, pain intensity, and the Revised Fibromyalgia Impact Questionnaire.
Muscle frequency, which reflects tone, and dynamic stiffness were significantly higher in the fibromyalgia group at all three sites. Logarithmic decrement, the elasticity parameter, did not differ between groups.
| Muscle | Tone and stiffness vs controls | Effect size |
|---|---|---|
| Upper trapezius | Significantly higher | Strong |
| Extensor carpi radialis brevis | Significantly higher | Weak to moderate |
| Medial gastrocnemius | Significantly higher | Weak |
| Elasticity (all sites) | No significant difference | Not applicable |
Why does the upper trapezius show the strongest signal?
It is the site where several stiffness findings converge, not just this one. A 2026 study in Physiotherapy Theory and Practice using shear wave elastography found significantly higher upper trapezius stiffness in office workers with chronic neck pain than in controls, with stiffness correlating positively with Neck Disability Index scores and fear-avoidance beliefs.
Two different conditions, two different measurement technologies, same muscle. That does not prove a shared mechanism. It does suggest the upper trapezius is a practical default site when you want a reading that is likely to move.
Does the stiffness reading track the patient's pain?
No, and that is the useful part. The only notable within-group correlation was a moderate positive relationship between medial gastrocnemius frequency and its pressure pain threshold. Stiffness and reported pain behaved as separate variables in this data, as they do in most of the stiffness literature.
For a fibromyalgia patient that separation is worth something. Pain intensity in this population moves week to week for reasons that have nothing to do with what you did in the room. A second measured channel gives you a comparison that is not hostage to how the patient slept.
How should you measure a fibromyalgia patient?
Mark your sites, keep the positioning identical, and keep the session short. These patients are frequently sensitive to sustained pressure, which makes extended palpation a poor assessment strategy and a worse experience. A fast handheld reading at a marked site is easier to tolerate and easier to repeat.
Two cautions. Group differences in a case-control study do not give you a diagnostic threshold, so measure to track a patient against their own baseline rather than against a published cutoff. And a higher number may reflect altered mechanical properties without indicating tissue damage. Say that out loud to the patient, because they will otherwise fill the silence with something worse.
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. Fibromyalgia patients are unusually exposed to the first group, because a fluctuating pain score makes real but slow change nearly impossible to feel.
Frequently Asked Questions
Do fibromyalgia patients have stiffer muscles?
In the published myotonometry data, yes. A 2026 case-control study in the European Journal of Applied Physiology found significantly higher tone and dynamic stiffness in the upper trapezius, extensor carpi radialis brevis, and medial gastrocnemius of 31 fibromyalgia patients compared with 31 age-matched controls.
Which muscle showed the biggest difference?
The upper trapezius. Effect sizes were strong there, weak to moderate in the extensor carpi radialis brevis, and weak in the medial gastrocnemius. If you measure one site in these patients, the upper trapezius is where the published signal is largest.
Was elasticity different in fibromyalgia patients?
No. Logarithmic decrement, the elasticity parameter, showed no significant difference between groups. Tone and stiffness separated the groups while elasticity did not, which is a reminder that these parameters are not interchangeable.
Does a stiffness reading track how much pain a fibromyalgia patient reports?
Not reliably. In the same study the only notable correlation was a moderate positive one between medial gastrocnemius frequency and its pressure pain threshold. Read stiffness as a separate channel of information, not as a proxy for reported pain.
Can soft tissue stiffness measurement diagnose fibromyalgia?
No. Fibromyalgia is diagnosed clinically using established criteria. Group-level differences in a case-control study do not establish a threshold that identifies the condition in an individual patient.
How should you measure a fibromyalgia patient without provoking symptoms?
Mark your sites, use consistent positioning, and keep the session short. These patients are often sensitive to sustained pressure, so a fast handheld reading at a marked site is easier to tolerate than extended palpation.
Why measure at all if the patient already knows they hurt?
Because pain intensity in fibromyalgia fluctuates enough to hide slow change. A second measured channel gives you something to compare across weeks when the pain score bounces around and the patient concludes nothing is happening.
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.