How Does Shockwave Therapy Work?

What is shockwave therapy?

How does shockwave therapy work?

In a nutshell, is simple. It’s a non-invasive treatment often used as an alternative to surgery for any MSK conditions, particularly tendons, ligaments, and bone.

There are other applications for men’s health and wounds/skincare, but for now, we will focus on MSK.

Shockwave is a SOUNDWAVE, not an electrical shock. This sound wave, aka acoustic pressure, generates energy that passes into tissues through a medium (water) to create mechanical stress on the tissue and activate a biological response in the cells. We know this as mechanotransduction.

With radial shockwave therapy (RPW), the energy hits the surface of the skin and impacts superficial structures.

For focused shockwave therapy (f-ESWT), the energy bypasses healthy tissues, converges and stimulates activity at a specific point.

The bio-effects of f-ESWT and RPW on MSK tissues will differ as these are related to the energy levels and pressure waveforms.

There is an argument that f-ESWT and RPW may complement each other. However, much of the literature compares the technologies rather than looking at how they could work together.

To find out more about radial vs focused shockwave, click here.

radial shockwave gallery 2

How are shockwaves generated?

There are a few ways a shockwave is generated, and this has an impact on:

The amount of energy delivered
The frequency it is delivered
The accuracy of the treatment
o All impacting the overall treatment outcome.

To find out more about the different types of shockwaves, click here.

How it works

Despite lots of clinical success across many studies for shockwave therapy, the mechanism of action is not fully known or understood for many applications.

Basically, we know a lot without knowing very much! But we will give you a quick run-through of the main principles of what we know so far.

There are lots of studies available investigating this looking at particular areas, e.g. tendons, wound care, and bone.

Haupt (1997) proposed four possible mechanisms of ESWT on tissue. 1

1. Physical Phase – physical actions of shockwave therapy
Positive pressure to generate absorption, reflection, refraction and transmission of
energy to tissue and cells. 2

Negative pressure causes a tensile phase which induces cavitation, ionisation of
molecules, cell membrane permeability.

2. Physicochemical phase

Stimulate cellular activity to release biomolecules such as adenosine triphosphate (ATP).

ATP release leads to cell signalling pathways being activated, like T-Cell proliferation 3 and extracellular signal-regulated kinase (ERK) 4 .

3. Chemical Phase

Shockwave has been shown to alter the chemical balance of biological tissues by;

Changing the functions of the ion channels in the cell membrane
Altering the calcium mobilization in cells. 5,6

All help the transport of ions across the plasma membrane to regulate cell potential, which plays an essential role in neural communication, nerve conduction, and muscle contraction.

4. Biological Phase

Studies into shockwave therapy have shown how it can modulate:

Angiogenesis
Wound healing
Bone healing
Inflammation

Here is a headache of a table showing you all the documented up-regulation and down-regulation factors.

how it works

*Table sourced from Moya et. al. (2018) The Role of Extracorporeal Shockwave Treatment in Musculoskeletal Disorders.

But don’t worry, you do not need to know this in detail. This is more of a “making you aware” of what shockwave therapy can stimulate!

Differences in biological effects between focused and radial shockwave

Focused shockwave AND radial pressure wave:

Stimulation of circulation (vasodilation)
Release of Substance P
Increase in cell wall permeability

Focused shockwaves ONLY:

Release of nitric oxide to increase cell metabolism, angiogenesis
Reduce non-myelinated nerve fibres
Anti-inflammatory effect
Release of growth hormones/factor

Indications

The differences in biological response between focused shockwave and radial pressure wave therapy have an impact on what you can treat, with good clinical effects.

It must be said that shockwave is very safe, and some of the indications are still somewhat experimental. You may hear anecdotal applications, and there are some indications that may be outside your scope of practice.

If you have any questions about the application, speak to our clinical specialist team for advice, which is always FREE!

Overall

There is substantial evidence to suggest focused shockwave therapy, and radial shockwave therapy stimulates a variety of cellular responses linked to tissue healing.

NB. that many of the studies are performed on animal models.

We don’t fully understand the relationship between energy levels and the effects on tissues raising the questions:

Can we be over-stimulating?
Are under-treating?

Shockwave therapy is fundamentally a mechanical load delivered at a specific point in the tissues.

Thinking about the gym and weights, the MSK system responds to mechanical load/input differently, making us think, should we stick to protocols or vary our treatments – we try and answer that question here.

Despite this, it is clear shockwave therapy is safe and effective and stimulates tissue healing.

Get in touch

If you have any more questions about Shockwave and how it works, contact us to speak to our team, who are here to help and advise!

References

1. Haupt G. (1997). Use of extracorporeal shockwaves in the treatment of pseudarthrosis, tendinopathy and other orthopedic diseases. J Urol. Jul;158(1):4-11.

2. Ogden JA, et. al. (2001) Principles of shockwave therapy. Clin Orthop Relat Res. 2001 Jun;387:8-17.

3. Yu T, et. al. (2010). Shockwaves increase T-cell proliferation and IL-2 expression through ATP release, P2X7 receptors, and FAK activation. AmJ Physiol Cell Physiol. Mar; 298(3): C457-64.

4. Weihs AM, et. al. (2014). Shock wave treatment enhances cell proliferation and improves wound healing by ATP release-coupled extracellular signal-regulated kinase (ERK) activation. J Biol Chem. Sep 26;289(39):27090-104.

5. Jan CR, Huang JK, Tseng CJ. (1998). High-energy shock waves alter cytosolic calcium mobilization in single MDCK cells. Nephron. ;78(2):187-94.

6. Frairia R, Berta L. (2012). Biological effects of extracorporeal shock waves on ﬁbroblasts. A review. Muscles Ligaments Tendons J. Apr 1;1(4):138-47.