Interferential Therapy


Stort Physio leads the UK and the world in the clinical application of Interferential Therapy.


Wendy Emberson has been working with Interferential Therapy (IFT) for the last 35 years and is the world leader in the clinical applications and use of this electro-therapeutic technique.

It is estimated that Wendy has  carried out more than 123,000 treatments since she was involved with the development of the first British designed machines in the late 1970’s.

She is currently writing her second textbook on IFT and is working on the next generation of machines with a UK manufacturer.

What is IFT?

Interferential Therapy (IFT) is a low frequency current treatment which was invented in Austria in the late 1940’s. The first machines came into the UK in 1949. The wide range of frequencies available in the British designed machines has extended the range of conditions that can be treated within a physiotherapy programme.

Essentially, IFT is a system of introducing a range of low frequency currents that the body itself produces. These low frequency currents stimulate different systems, so we use different frequencies for different effects.

Conditions that we can treat with IFT

IFT has a wide range of effects:

  • Increases the healing rate of soft tissue injuries - muscles, tendons, and ligaments
  • Increases circulation
  • Speeds the recovery rate of nerves and bone
  • Pain relief
  • Chest conditions, such as asthma (two undergraduate research projects confirmed that it is a better broncho-dilator than ventolin)
  • Bowel conditions, such as IBS

Patients with conditions as diverse as cirrhosis of the liver, IBS and asthma have been successfully carried out based on the research of Professor Lilyana Nikolova in the mid 1980s. Unfortunately, students at university can only look at research carried out within the last 5 years or so and are unaware of the work carried out before then.

The more common conditions that respond to IFT are all the musculo-skeletal conditions including low back problems and sports injuries.

History of IFT 

The equipment we use was developed some years ago when Wendy Emberson collaborated with the Bioengineering Department at St Batholomew’s Hospital, London to produce the first British machine. Four of these bioengineers formed SNS Bioengineering Ltd and Wendy worked with them again to design and develop the second British machine.

Since SNS Bioengineering ceased trading following the death of the director, there have been no new  machines on the market that can provide all the frequencies and treatment applications that we can offer.

With the advent of the much needed next generation of machines, Wendy will be able to start teaching again and be able to publish her second edition of the textbook.

In the meantime, our patients will continue to have the benefit of IFT as part of their treatment programmes.


There is a great deal of research evidence into the clinical effects of low frequency currents. At Stort Physio, we are continuing to gather copies of all the research of the last 66 years to build a complete library and information resource, as well as to develop full research projects of our own.

Interestingly, this research is not limited to the physiotherapy profession, but other researchers are unaware of the existence of Interferential Therapy.

One example is the Royal London Hospital who are using low frequency currents applied via an acupuncture needle, in one of the nerves in the leg, to stimulate normal function of the bowel.

Very recently, Google and Glaxo Smith Kline are looking at using low frequency "implants" to affect diseases such as type 2 diabetes. We have known which frequencies will stimulate the pancreas to produce insulin for some 20 years now, but the problem there is how to monitor the results and change the "dose" according to the sugar levels.

In the late 1970’s at St Mark’s and St Bartholomew’s Hospitals carried out a trial using IFT for IBS with very successful results - unfortunately they didn’t publish these results! This is just one area of interest where we intend to repeat the research and publish the results.

There are very few side effects when used correctly by physiotherapists with the right post graduate training, under the right circumstances and for the right conditions.

At Stort Physio we have begun compiling a series of single case studies that demonstrate the range of conditions that can be treated using IFT as part of the Treatment Plan.

With the advent of new equipment, with new features, we hope to be able to start full scale research into the actual mechanisms.