What is Electrotherapy? Overview & How it Works

what is electrotherapy?

If you’re wondering; what is electrotherapy treatment?, then you’re certainly in the right place.  

Perhaps you’re looking into treatment for yourself or you want to learn how and when to suggest electrotherapy treatment to your clients?

Whatever your reason, we have everything you need to know about the treatment, including what it is, how it works, and everything in between! 

However, if you want to advance your sports massage therapist career opportunities and offer a range of services including electrotherapy, you can do this with our Level 3 Sports Massage CourseFind out more by downloading our latest prospectus

What is Electrotherapy? 

While there are multiple electrotherapy modalities that help to define electrotherapy itself, it is essentially a medical treatment that is used for pain relief and stimulation in musculoskeletal (soft tissue) injuries.

Some patients also undergo TENS treatment in particular to improve their daily movement and overall quality of life, perhaps alongside yoga or other gentle exercise methods. If you are considering becoming a yoga instructor at some point, this may mean that electrotherapy treatment is something that you should learn about, should your clients be looking to improve their mobility. 

In most cases, electrotherapy and physiotherapy treatments are used alongside each other to tackle these issues rather than being used as an explicit solution. 

We know that the name makes it sound intimidating, but don’t panic. It’s definitely nowhere near as scary as historic ‘electrical treatments’ that make up electrotherapy history, which often involved a sharp shock or two!

While we won’t go into the details of these ‘shocking’ treatments, we’ll stick to those that truly paved the way to define electrotherapy as it is used today. 

The History of Electrotherapy 

history of electrotherapy graphic

Luigi Galvani (who rose to prominence in the 18th century) is noted as one of the first to discover key information that relates directly to how electrotherapy is performed today. 

In his article ‘Lessons from the Father of Electromedicine’, Forest Tennant (M.D. and Doctor of Public Health) writes:

Another investigation that has direct relevance to pain treatment today is Dr. Galvani’s work showing that damaged nerves emit an electric current. 

The importance of these early findings is that an injury to nerves, as found in the typical pain patient, emits an electric current that leaks into and pools in the tissue around the damaged nerves. It is this “free” or “pooled” electricity that may produce pain and inflammation.

A lot has changed since these discoveries were made (sometimes through admittedly risky experiments), but it’s still interesting to learn about those that led to modern techniques and practices. 

You’ll be glad to know that modern electrotherapy treatment involves a light electrical stimulation that is completely safe. It’s extremely common in the world of sport and was even a key modality used by sports medicine professionals at the 2012 Olympic Games

Fitness professionals have been widely known to refer their clients for electrotherapy treatment, or to work with clients who are undergiong it, as it is usually used alongside treatments such as sports massage therapy to treat various musculoskeletal conditions, and get athletes back on their feet. 

Becoming a sports massage therapist is actually one of the most profitable career moves in the fitness business, so do keep this in mind... 

One notable difference between practices used in electrotherapy history and those that we use today is that here in the 21st century, we must justify why we are using a specific modality alongside other treatments for a patient’s injury. 

If the treatment can’t be justified, then it shouldn’t be used at all. 

Electrotherapy Modalities: The Different Types of Electrotherapy

electrotherapy modalities image

When we look at the question how does electrotherapy work?, it’s difficult to give a holistic answer given the amount of different treatments that are used. 

To make things easier, we’re going to give a breakdown of the different types of electrotherapy that are used in sport and discuss how they work individually, as well as the injuries that they are used to treat. 

In electrotherapy for sports injuries, TENS, ultrasound, and shockwave therapy are the most commonly used modalities, which we’ll talk through now! 

TENS (Transcutaneous Electrical Nerve Stimulation) 

TENS electrotherapy treatment is one of the most commonly used treatments in sports injury physiotherapy. 

It’s non-invasive, extremely safe, and can even be prescribed to and carried out by patients themselves!  

How does it work?

image of electrotherapy modalities

It involves passing a mild electrical current through the muscles and nerve fibres to alleviate pain in the area, through the use of a handheld battery-powered device. This means that it is one of the main treatments used in electrotherapy for muscles that are injured or are experiencing pain. 

The device works by supplying an electric current to the electrodes that are connected to it. 

The electrodes are the sticky pads that you see attached to the patient’s skin below, and they allow the current to safely pass through the body. 

TENS electrotherapy treatment is actually one of the most popular choices of treatment that links directly to the Pain Gate theory, that we talk about in-depth later on in this article. 

It’s because of this theory that we know how TENS works for pain relief, so it’s a great thing to read up on if you want to know more! 

The idea is that when pain is experienced, it travels along the spinal cord through the microscopic fibres that run the length of it, and end at the dorsal horn. After this point, only one impulse is able to pass through at a time. 

So, if another impulse replaces the pain impulses, it can effectively overthrow them… 

When an electrotherapist uses TENS, they look to replace the pain impulses with another sensation at the site of injury created by the electrical current. 

This will then pass through the ‘gate’ at the dorsal horn rather than the pain impulses, and block their transmission to the brain. 

Essentially, TENS electrotherapy treatment works by delaying the signals of pain that are transmitted from the nerves to the brain. It replaces the pain impulses with an alternative impulse; the electrical current. 

This means that the patient’s awareness of the pain they’re experiencing at the site of injury is lessened during treatment, and can improve overtime! 


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What injuries is it used to treat? 

TENS can be used to treat a long list of common injuries, providing that the source of them is appropriately linked to a relevant musculoskeletal disorder or ailment (that is fine to be treated with electrotherapy). 

We’ll dive into electrotherapy contraindications later on in the article to give more clarity on the topic, but for now let’s take a look at the injuries treated by TENS themselves:

  • Muscle strains 
  • Tendonitis 
  • Knee osteoarthritis 
  • Neck pain
  • Shoulder pain 
  • Spinal pain 
  • Postoperative pain
  • Phantom limb pain
  • DOMS 

As you can see, most of these injuries are pretty vague when viewed alone, as they can be sustained through an endless list of possibilities. 

This is why it’s important for an electrotherapist to predetermine the cause of the pain with the patient and other health professionals that are involved in their treatment, and discuss whether the use of electrotherapy for sports injuries is relevant in each case. 

If TENS can be justified for the injury in question then treatment is good to start! 

Ultrasound Electrotherapy 

As opposed to diagnostic ultrasound (which is used to capture internal images of the body), electrotherapy ultrasound is classed as an electrotherapy treatment, although it does not involve an electrical current as such. 

It’s actually classed as an EPA (electro physical agent), as it involves passing energy or thermal energy through the patient’s body to alleviate pain symptoms. 

Deep heating is the predominant benefit from the thermal energy that is used, whereas ‘cavitation’ is the proper name for the non-thermal benefits that take place simultaneously, which we’ll take a look at shortly!  

How does it work?

electrotherapy modalities

A therapeutic or electrotherapy ultrasound device is different to that used during TENS, not only in appearance (as it’s usually less portable), but through the way that the treatment itself is administered. 

For starters, a electrotherapy ultrasound device will have an ultrasound transducer, otherwise known as a ‘sound head’ rather than electrodes. 

The electrotherapist will apply a small quantity of gel to the patient’s injured area and move the sound head in a continuous circular motion throughout the treatment. During this time, the piezoelectric waves that are created at the heart of the device are released from the sound head as ultrasound waves, and enter the tissues within the injured area. 

This is when the therapeutic effects begin, both thermal and non-thermal as we mentioned earlier. 

The deep heating of the soft tissues in the area will cause a spike in circulation, which in turn aids the overall healing process as well as reducing any pain or tightness. 

In terms of the non-thermal effects, they are created through a process known as cavitation. 

During this process, a microscopic oscillation (a back and forth movement) occurs thanks to the energy that is emitted through the area by the ultrasound waves. 

This creates a formation of gas bubbles that undergo rapid expansion and contraction, and theoretically speed up the healing process on a cellular level! 

This form of cavitation that is stimulated by an electrotherapist is known as stable cavitation, and provides healing benefits in its controlled form. However, unstable cavitation is an undesirable effect that the electrotherapist should avoid during treatment, as it can actually damage soft tissues. 

What injuries is it used to treat? 

  • Tendonitis 
  • Muscle strains
  • Ligament sprains
  • Joint inflammation or stiffness 

If you would like to learn more about this subject, you can read these great articles on Sports Massage Therapy:

Shockwave Therapy 

Shockwave therapy in electrotherapy is different again to the previously mentioned electrotherapy modalities, as it’s administered with the intent of sudden pain relief and mobility restoration, whereas TENS and ultrasound use more of a gradual approach. 

That being said, it’s still not as aggressive as the name suggests, and doesn’t involve any electric shocks! 

How does it work?

As with the previously mentioned electrotherapy modalities, shockwave therapy involves its own form of machine, which is connected to a probe. 

shockwave therapy image

During shockwave therapy in electrotherapy, ultrasound gel is applied to the troublesome area by the electrotherapist before the probe makes contact with the skin. 

Once it is placed onto the skin, however, high amplitude shockwaves are emitted from the probe into the most painful area of the injured site. 

The shockwaves rapidly travel through the external layer of skin, and spread out in a radial wave, which creates an inflammatory-like response in the surrounding area (namely in the injured tissues). 

This triggers the body to increase blood flow to the area, as well as the metabolism of the injured tissues. It activates the healing process and gets the ball rolling immediately, in comparison to other treatments. 

Most patients report no painful side effects of shockwave therapy during electrotherapy, but sometimes state that they experienced an uncomfortable or strange sensation (which is perfectly normal, and is outweighed by the beneficial effects of the treatment). 

C.J. Wang in his 2003 overview on shock wave therapy in musculoskeletal disorders states:

The application of shock wave therapy in certain musculoskeletal disorders has been around for approximately 15 years, and the success rate in non-union of long bone fracture, calcifying tendonitis of the shoulder, lateral epicondylitis of the elbow and proximal plantar fasciitis ranged from 65% to 91%. The complications are low and negligible.

This is pretty reassuring when it comes to the safety of shockwave therapy, and supports the idea that it is pretty actionable in comparison to other treatments that one can opt for when looking to treat musculoskeletal conditions. 

What injuries is it used to treat? 

  • Plantar fasciitis 
  • Elbow pain
  • Shoulder pain 
  • Tendinopathy 

Electrotherapy and the Pain Gate Theory 

electrotherapy pain gate theory

Whether you’re looking for a way to treat an injury that you yourself have sustained, or you’re here because you’re thinking of becoming an electrotherapist/someone who refers their clients for electrotherapy (and therefore need to know the ins and outs of the treatment), it’s a great idea to read up on the electrotherapy pain gate theory. 

We’re not going to go into every last scientific detail, but we’ll certainly give you an overview of the general ideas surrounding the theory, as well as the relevant references to read if you do want to know more! 

The pain gate theory originated in 1965, when Ronald Melzack (psychologist and Professor) and Patrick D. Wall (leading neuroscientist and the ‘world’s leading expert on pain’) published a paper detailing the ins and outs of their findings. 

That’s not to say that everything that they found was correct, as Lorne M. Mendell states in 'Constructing and Deconstructing the Gate Theory of Pain'

Although subsequent experiments and clinical findings have made clear that the model is not correct in detail, the general ideas put forth in the paper and the experiments they prompted in both animals and patients have transformed our understanding of pain mechanisms.

While it’s true that the ideas presented by Melzack and Wall in their original version of the theory were not completely correct, they still provided a great insight into how we view pain and it’s processes within the body. 

This is important to grasp before we move on, and we’d definitely suggest reading Mendell’s (Ph.D in Neurophysiology) paper on the subject! 

Outline of the Pain Gate Theory 

We’re going to make our outline of the theory as simple and concise as possible (to avoid boring you with every last detail). 

In short, it refers to the way that we experience pain, and provides us with an understanding of how to actively deter pain impulses from reaching the brain. 

When we sustain any kind of injury, pain impulses are created at the injured site. You may think that this is it, and that our bodies experience pain immediately from this single process, but this isn’t the case! 

Before we’re able to feel the pain, the impulses must travel along the spinal cord through the fibres that run along it, also known as A-delta and C fibres.

These fibres end at the dorsal horn, which acts as a ‘gate’ and only allows one impulse to pass through at a time. 

graphic of electrotherapy pain gate theory

Using this information it’s easy to see that when the impulse reaches the dorsal horn, one of two things will happen. 

It will either be transmitted to the brain through the transmission cells within the dorsal horn, or stopped altogether by the inhibitory interneurons that are there to obstruct any action from transmission cells (should they be overpowered by another impulse). 

This impulse will then travel to the brain, which then processes it as pain and reflects this signal back to the nerve endings. 

To make this clear, we’ll use a quick example. 

Say you go for a run and sprain your ankle. The first thing that you would do is apply ice to the area, in an attempt to combat the swelling and pain that you’re feeling. 

Your skin will register the cold sensation from the ice, and transmit a signal that travels all the way up the spinal cord to the dorsal horn, and replace the pain impulse. It will then pass through to the brain, and deaden the pain that you’re feeling since only one impulse can pass through at a time!  

How the Pain Gate Theory Relates to Electrotherapy 

The relation between electrotherapy to the pain gate theory is easily explained, as electrotherapy is used to deter pain by replacing pain impulses through an electrical current. 

To explain this in a little more depth, it involves nociceptive fibres (A-Delta and C fibres) that have a higher activation threshold than mechanoreceptive fibres (A-beta fibres). 

When the electrical currents used during TENS, Ultrasound and Shockwave therapy are delivered across the patient’s skin, it becomes possible to identify and then stimulate specific mechanoreceptive fibres. 

This then prevents the signals from the nociceptive fibres from passing through the dorsal horn and reaching higher centres of the brain. 

In theory, if this is done correctly then the client should see a significant reduction in pain! 

How to Promote Electrotherapy to your Clients 

what is electrotherapy graphic

If you’re a fitness professional looking into getting qualified in electrotherapy, it’s important to know the reasons for doing so before you invest in an electrotherapy course. 

Not only should you consider the financial benefits, as this is an important element in professional development for personal trainers and fitness professionals, but you should make it your mission to find out exactly how adding electrotherapy treatment to your services or the knowledge behind referring your clients for treatment will benefit them and their rehabilitation. 

While the course that we offer doesn’t ‘qualify’ you to practice this treatment, it definitely serves as a gateway insight into the topic. 

It allows fitness professionals to understand why a client of theirs may benefit from being referred to a physiotherapist or sports therapist to receive electrotherapy, and also gives them a starting point into finding out how they can get qualified in electrotherapy application itself. 

By all means a professional could purchase a TENS machine online and administer treatment to themselves, but they would have to check out their insurance policy before they placed it on a client; in most cases they may not be covered to do so. 

Luckily for you, we’ve put together a list of the general benefits of electrotherapy, along with a quick-fire explanation of the scenarios where it’s relevant to suggest it as a treatment method. 


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Benefits of Electrotherapy

While there is some debate surrounding the effectiveness of electrotherapy treatment, this is outweighed by a great deal of scientific research that supports the idea that it is indeed a beneficial method of physical therapy. 

It’s important to remember that electrotherapy is rarely used in isolation, and that it will typically be applied alongside other physical therapy or sports rehabilitation treatments, such as sports massage therapy. 

NOTE: if you're already practising as an SMT, check out our sports massage marketing ideas and boost your business! 

Irena Kola (Faculty of Medical Technical Sciences, University of Medicine, Albania) in her study ‘Rehabilitation of Lower Back Pain with Manual Therapy and Electrotherapy’ writes: 

By concluding, the most effective therapy for the rehabilitation of the lower back pain is combined therapy with manual therapy, exercises and electrotherapy. This conclusion is also supported by International evidence.

While this is just one example, it certainly captures what we’re trying to say about the effectiveness of electrotherapy treatment alongside other means of rehabilitation. 

electrotherapy modalities graphic

As pain relief is one of the most significant benefits of electrotherapy, for example, the treatment can aid the patient in being able to partake in exercise, which is incredibly important for their overall recovery. 

Here’s how electrotherapy benefits those suffering from musculoskeletal injuries or conditions: 

  • Pain relief (chronic, post-surgical acute and post-injury) 
  • Relaxation of muscle spasms
  • Boost in blood flow and circulation (especially in injured areas)
  • Improved range of motion 
  • Neuromuscular re-education through direct stimulation 
  • Prevention of muscular atrophy (which is common in those who cannot exercise frequently) 
  • Improved chance of successfully delivering prescription drugs to affected areas via EMDA 
  • Prevention of post-surgery deep vein thrombosis 

As well as making your client aware of the advantages of electrotherapy, you should always be  sincere and make them aware of the contraindications as well as any possible disadvantages of the treatment, which we’ll talk about shortly. 

However, to sum this up, here are our tips for promoting electrotherapy to clients:

  • Only ever offer electrotherapy to clients/recommend that they see a specialist and receive electrotherapy treatment when are suffering from an injury/condition that it has been scientifically linked to
  • Always inform them of the success rate of any electrotherapy modalities that are useful in treating their specific condition 
  • Remain sincere and act in their best interest at all times; only ever administer electrotherapy if you truly believe it will benefit the client 
  • Ensure that they’re made aware of the advantages AND the disadvantages, so that they can make their own informed decision 

Not only will following this advice help you to remain benevolent and supportive from the client’s perspective, but it will ensure that you’ve followed the best practices should any form of bad situation arise. 

Check out our article on personal trainer insurance for more information on this topic, as it covers everything that fitness professionals need to know about insuring themselves and their services! 

Electrotherapy Contraindications

electrotherapy contraindictations image

When answering the broad question, 'what is electrotherapy?', it’s important to go through the contraindications of the treatment so that those interested understand what it shouldn’t be used for. 

It goes without saying that anyone looking to get qualified in electrotherapy should ensure that they understand this, perhaps before learning anything else, as it’s vital for safe practice. 

So, what are the electrotherapy contraindications? And how can an electrotherapist ensure that they are administering treatment safely? 

Electrotherapy contraindications:

  • Electrotherapy should not be used as a treatment of symptomatic pain (unless the pain has been specifically diagnosed) 
  • It should not be applied to swollen, inflamed, or infected areas of skin (e.g. varicose veins)
  • If a patient displays or discloses symptoms of any serious infectious diseases, they should not undergo electrotherapy treatment 
  • Any areas of the body with cancerous ulcers, wounds, abscesses, tumours, etc. should not be treated with electrotherapy 
  • Pregnant women should avoid electrotherapy altogether as it has not been cleared for use during pregnancy 
  • Children should never be treated with electrotherapy 
  • Those with pacemakers or cardiovascular disease should not be treated with electrotherapy 
  • Electrotherapy should never be applied to the anterior neck or through the head 

Although professionals must abide by this list, there may be rare occasions where electrotherapy is used on those listed above. 

However, this should be done with a great deal of caution as research is inconclusive in terms of the negative effects that could arise in patients if any of the electrotherapy contraindications apply. 

If you want to read more about contraindications, you can read our article on Sports Massage contraindications.  

Disadvantages of Electrotherapy 

what is electrotherapy contraindictations

This may sound particularly negative, but every treatment comes with its disadvantages as well as contraindications (which are mostly interlinked). 

There are always rare cases of things not going as planned, but as long as you make yourself aware of this (as you certainly will through gaining a relevant qualification), you should be prepared to relay this information to your clients. You’ll also be prepared in the event of one of the listed possibilities occuring. 

The disadvantages of electrotherapy are as follows: 

  • In some (extremely rare) cases, it has been known to cause allergic reactions and irritations on the skin, and/or pain from the electrical charge 
  • It cannot be applied to an injury that is still bleeding 
  • It cannot be used to treat an area that is classed as ‘cancerous tissue’, or that is infected 
  • It cannot be used on body areas that are deemed ‘sensitive’ 
  • It cannot be used to treat the back of pregnant women (and should be avoided by pregnant women in general) 

Hopefully this gives you some clarity, and re-assurance in the sense that there aren’t too many disadvantages of electrotherapy treatment, as it is pretty non-invasive and low-risk. 

On the whole, there is nothing much to worry about if a client is properly screened, and electrotherapy has been cleared for use for their specific injury or condition.  

Before You Go! 

Whether you’re a fitness professional looking to expand on your continued professional development or you’re looking into undergoing electrotherapy treatment yourself, you'll have found your answer to ‘what is electrotherapy?’. 

Interested in advancing your career as a sports massage therapist? You can do exactly this with our Level 3 Sports Massage Course! By developing your knowledge, you'll not only improve your skills but also increase your employment opportunities.

You can also download our latest prospectus here for more information on our range of fitness courses! 


  1. Grant, M.E., Steffen, K., Glasgow, P., Phillips, N., Booth, L. and Galligan, M., 2014. The role of sports physiotherapy at the London 2012 Olympic Games. British journal of sports medicine, 48(1), pp.63-70.
  2. Practical Pain Management. 2020. Lessons From The Father of Electromedicine — Dr. Luigi Galvani. [ONLINE] Available at: [Accessed 17 March 2020].
  3. Wang, C.J., 2003. An overview of shock wave therapy in musculoskeletal disorders. Chang Gung medical journal, 26(4), pp.220-232.
  4. Kola, I., Frroku, E. and Kola, S., 2019. Rehabilitation of Lower Back Pain with Manual Therapy and Electrotherapy. life, 4, p.6.

Written by Chloe Twist

Fitness Content Executive, OriGym

Join Chloe on Facebook at the OriGym Facebook Group

Chloe graduated with a BA (Hons) English and Creative Writing from Liverpool John Moores University and prior to OriGym worked at J&R Digital Marketing Agency on the Liverpool 'Female Founders' series. Since joining the company, she has become a qualified Personal Trainer and advanced Sports Nutrition Specialist. Chloe’s professional interests intersect content-development and the world of online fitness, especially across social media and YouTube, and Chloe has herself contributed pieces on fitness and weight loss to sites including the Daily Star and The Express. Outside her day-to-day role, Chloe enjoys playing the guitar, gaming and kettlebell training. 

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