Not reliably, at least not the stiffness you can measure. A 2024 trial of six weeks of IASTM found better ankle range of motion and stretch tolerance with no significant change in muscle or tendon stiffness on shear wave elastography. Pain and function did improve in a 2025 meta-analysis of 11 randomized trials.
What did the trials measure?
The clearest result comes from a study that separated range of motion from tissue stiffness and reported both. A 2024 study in Sports applied IASTM to one leg three times a week for six weeks and used the untreated leg as a within-person control. Ankle dorsiflexion improved. Stretch tolerance, measured as maximal passive torque, improved. Muscle and tendon stiffness on shear wave elastography did not change significantly. The control limb did not change on any measure.
That combination is the useful part. The patient moves further, and the mechanical property of the tissue stays roughly where it was. Both things can be true at once.
Does the wider evidence agree?
On pain, yes. On stiffness, there is not enough data to pool. A 2025 meta-analysis in BMC Musculoskeletal Disorders covering 11 randomized trials and 427 participants found moderate-certainty evidence that IASTM reduces patient-reported pain and low-certainty evidence that it improves function. The authors reported only a single data point per study for pressure pain threshold and stiffness outcomes, which was too little to analyze together.
A 2026 review in Frontiers in Physiology reached a similar place across myofascial and fascial-targeted mechanical techniques. Short-term improvements in pain and range of motion show up consistently. Evidence for lasting structural change in muscle or fascia does not.
| Outcome | What the evidence shows | Certainty reported |
|---|---|---|
| Patient-reported pain | Reduced after IASTM | Moderate |
| Function | Improved after IASTM | Low |
| Range of motion | Improved short-term | Consistent across reviews |
| Measured muscle stiffness | No significant change at six weeks | Single trial, too few studies to pool |
| Long-term structural change | Not demonstrated | Inconsistent |
Why would range of motion improve without stiffness changing?
Stretch tolerance is the most likely explanation. The patient allows the joint to be taken further before the movement stops. The angle you record goes up. The passive mechanical resistance of the muscle, which is what a stiffness reading estimates, has not necessarily moved.
This matters because the two get reported as if they were the same finding. A patient who gained 8 degrees of dorsiflexion has gained something real. It may reflect a change in tolerance rather than a change in the tissue, and only one of those is captured by a stiffness measurement.
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 shown that their soft tissue stiffness was still elevated.
What should this change in practice?
Keep the technique and narrow the claim. Telling a patient that IASTM broke up their tight tissue sets an expectation the evidence does not support. Telling them it may reduce their pain and improve how far they can move is supported and still worth saying.
The measurement habit follows from that. If you want to know whether the tissue itself changed in a specific patient, group averages will not tell you. You need a reading at baseline and another at a consistent interval, taken at the same site with the patient in the same position. That is the only way a stiffness number becomes evidence about this patient rather than about a trial population.
Hold the interpretation loosely either way. A stiffness reading that drops after treatment may reflect a short-term change in the tissue. It does not indicate that pain will follow, because stiffness and pain move independently.
Frequently Asked Questions
Does IASTM reduce muscle stiffness?
Not reliably, based on objective measurement. A 2024 trial of six weeks of IASTM found improved ankle dorsiflexion and stretch tolerance with no significant change in muscle or tendon stiffness measured by shear wave elastography.
Does IASTM work at all then?
Yes, for pain and function. A 2025 meta-analysis of 11 randomized trials in 427 participants found moderate-certainty evidence that IASTM reduces patient-reported pain and low-certainty evidence that it improves function.
Why does range of motion improve if stiffness does not change?
The most likely explanation is stretch tolerance rather than tissue change. The patient tolerates being taken further into range, which raises the measured angle while the passive mechanical property of the muscle stays where it was.
Does Graston Technique change tissue structure?
The evidence for lasting structural change is thin. A 2026 review of myofascial and fascial-targeted mechanical interventions reported short-term gains in pain and range of motion but inconsistent evidence for long-term structural change in muscle or fascia.
Should you stop using IASTM?
No. The pain and function findings are real. The change worth making is what you claim it does and what you measure to check, because pain relief and reduced stiffness are separate outcomes that move independently.
How would you know if IASTM changed stiffness in a specific patient?
You would need a stiffness reading at baseline and again at a consistent interval, taken at the same site and position. Group averages in trials cannot tell you what happened in the patient in front of you.
How long do the effects of IASTM last?
Most trials measure immediately after treatment or over a few weeks, so durability beyond that is largely unknown. Reported gains in pain and range of motion are consistently described as short-term rather than lasting.
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.