Chapter 3
How Does Shockwave Therapy Work?
Understanding the Science Behind ESWT
One of the questions patients ask most often is:
“How does shockwave therapy actually work?”
The honest answer is that research is still evolving. Scientists do not believe there is one single mechanism responsible for the effects of Extracorporeal Shockwave Therapy (ESWT). Instead, current evidence suggests that ESWT influences several biological and neurological processes that may support recovery in some long-standing tendon conditions.
This is why shockwave therapy should be viewed as part of a comprehensive rehabilitation programme, rather than a treatment that “repairs” tendons by itself.
The Body is Constantly Repairing Itself
Many people imagine the body as a machine that simply wears out.
In reality, your body is continually repairing, rebuilding and adapting.
Every day:
- Bone is being remodelled.
- Muscle fibres are repaired.
- Skin renews itself.
- Tendons adapt to the forces placed upon them.
This process is called tissue remodelling.
Healthy tissues constantly adapt to the demands placed upon them.
When the demands exceed the tissue’s capacity for a prolonged period, symptoms can develop.
Understanding Tendon Adaptation
A healthy tendon is never static.
Every time you:
- walk
- run
- climb stairs
- play golf
- lift weights
- carry shopping
your tendons experience load.
The cells within tendons detect this loading and respond by maintaining or adapting the tissue over time.
Appropriate loading generally encourages tendons to become stronger and better able to tolerate everyday activities.
Too much loading, too quickly, or inadequate recovery may exceed the tendon’s current capacity.
What Happens in Persistent Tendinopathy?
In persistent tendon pain, several changes may occur.
These can include:
- reduced organisation of collagen fibres
- altered tendon cell activity
- changes in the surrounding extracellular matrix
- increased sensitivity of local nerves
- reduced ability of the tendon to tolerate repeated loading
Importantly, this does not necessarily mean the tendon is “wearing away” or “torn.”
Many people have structural changes on imaging but experience little or no pain.
Likewise, some people experience significant pain despite relatively minor imaging findings.
This highlights why treatment decisions should not be based on scans alone.
The Goal of Shockwave Therapy
Rather than simply trying to reduce pain, ESWT aims to influence the biological environment within the tendon while rehabilitation exercises progressively improve its ability to tolerate load.
Think of it like gardening.
Imagine a neglected garden.
Removing weeds alone won’t produce healthy flowers.
Similarly, simply reducing pain is rarely enough.
The soil needs improving.
Plants need watering.
Sunlight is needed.
Over time, healthy growth becomes possible.
Shockwave therapy can be thought of as helping prepare the environment, while exercise provides the ongoing stimulus needed for adaptation.
Mechanical Stimulation
Shockwave therapy delivers rapid acoustic pressure waves into tissue.
These mechanical forces are believed to stimulate cells within the tendon.
Cells respond to mechanical forces throughout the body.
For example:
- Bone becomes stronger when loaded.
- Muscles become larger after resistance training.
- Tendons adapt when exposed to appropriate exercise.
Shockwave therapy provides another form of carefully controlled mechanical stimulation.
Cellular Responses
Research suggests ESWT may influence tendon cells (tenocytes).
These specialised cells help maintain tendon structure.
Laboratory studies suggest mechanical stimulation may encourage cellular activity associated with tissue remodelling.
Although research continues, scientists believe this response may contribute to improvements seen in some patients.
Blood Vessel Formation (Neovascularisation)
Healthy tissues require oxygen and nutrients.
Some laboratory studies suggest ESWT may encourage the formation of new small blood vessels in treated tissue.
This process is known as angiogenesis.
Improved blood supply may support normal tissue repair processes, although the exact role in clinical recovery is still being investigated.
Growth Factors
Growth factors are naturally occurring proteins involved in healing.
Research suggests ESWT may influence the release of certain growth factors that participate in tissue repair and regeneration.
These include proteins involved in:
- cell communication
- collagen production
- blood vessel development
- tissue remodelling
These responses are part of the body’s own biology rather than something added from outside.
Collagen Remodelling
Collagen provides tendons with their strength.
In persistent tendinopathy, collagen organisation may become less orderly.
Shockwave therapy is thought to support the processes involved in collagen remodelling.
However, this is gradual.
It takes weeks to months for tendon tissue to adapt meaningfully, which is why exercise and patience remain essential.
Pain Modulation
Pain is produced by the nervous system, not by the tendon alone.
Current research suggests ESWT may influence pain through several mechanisms, including changes in how pain signals are processed at the treated area.
This may help explain why some patients notice a gradual reduction in symptoms over time.
Pain reduction is not immediate for everyone, and improvement often occurs alongside ongoing rehabilitation.
Why Exercise Still Matters
One of the biggest misconceptions is:
“Shockwave fixes the tendon.”
In reality:
Exercise remains the cornerstone of treatment for most tendon conditions.
Shockwave therapy may help create an environment in which the tendon responds more effectively to rehabilitation, but it does not replace the need for progressive loading.
Without appropriate exercise:
- strength may not improve
- movement patterns may not change
- load tolerance may remain limited
Successful rehabilitation depends on combining the right treatments at the right time.
Why Results Vary
Patients often ask:
“My friend had shockwave and improved. Will it work for me?”
Not necessarily.
Outcomes depend on many factors, including:
- the accuracy of the diagnosis
- how long symptoms have been present
- the specific tendon involved
- your general health
- smoking status
- metabolic health (such as diabetes)
- medications
- activity levels
- adherence to the rehabilitation programme
This is why no ethical clinician can guarantee success.
Recovery is a Process
Many patients expect recovery to follow a straight line.
Unfortunately, rehabilitation rarely works that way.
It is common to experience:
- good days
- bad days
- temporary flare-ups
- gradual improvement over weeks or months
These fluctuations do not necessarily mean treatment is failing.
Your physiotherapist will help you interpret symptoms and adjust your programme when needed.
Putting It All Together
Current evidence suggests ESWT may support recovery through a combination of:
- mechanical stimulation of tissue
- influencing tendon cell activity
- supporting collagen remodelling
- promoting angiogenesis (formation of new blood vessels)
- influencing growth factors involved in repair
- modulating pain signalling
These effects appear to work best when combined with:
- an accurate diagnosis
- progressive exercise
- education
- appropriate activity modification
- regular clinical review
Key Takeaways
- ESWT does not “repair” tendons overnight.
- It is believed to influence several biological processes involved in tissue adaptation.
- Research supports the idea that ESWT may complement rehabilitation for some persistent tendon conditions.
- Exercise remains the most important part of most tendon rehabilitation programmes.
- Recovery depends on many factors, including diagnosis, load management and patient engagement.
- Improvement is usually gradual rather than immediate.
Clinical Insight
The strongest evidence for ESWT is generally for selected chronic tendinopathies, particularly when symptoms have persisted despite appropriate conservative treatment. It should be offered as part of an evidence-informed treatment plan, with patients understanding both its potential benefits and its limitations.
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