Ultrasound Therapy and its Uses in Physiotherapy

Ultrasound therapy can be used in a variety of different situations, from treating a sprain to administering drugs. We'll tell you more about it in this article.
Ultrasound Therapy and its Uses in Physiotherapy

Last update: 30 July, 2020

The ultrasound is one of the pieces of equipment most commonly used by physiotherapists. Medical professionals have been employing ultrasound therapy for several decades now, using it to help diagnose and treat a number of different conditions.

While ultrasound is perhaps more commonly used as a diagnostic tool, we’ll be leaving that particular usage aside for today, to focus instead on the different applications of the ultrasound within the field of physiotherapy.

How does an ultrasound work?

An ultrasound machine sends small vibrations or mechanical waves into the body. While human beings are only capable of perceiving frequencies of up to 20,000 Hz, an ultrasound machine will operate in a frequency range of between 1 and 3 MHz. In other words, between 1 and 3 million cycles per second.

This means that we, as patients, won’t notice any effect. However, when we apply an ultrasound probe to a part of the body, it’ll produce waves, which cause the tissues in that area to vibrate very quickly. As well as vibrations, this will also produce heat, along with increased blood flow to the area. These two physical processes make ultrasound therapy so beneficial.

Finally, a study published in the Journal of Orthopaedic Research demonstrated that ultrasonic waves are particularly good at stimulating collagenous tissue. As a result, this kind of therapy usually works best on structures such as tendons, ligaments, fascia, and scar tissue.

Ultrasound therapy – methodology

Before using ultrasound, a physiotherapist will first apply a layer of gel to the skin. This is because an ultrasound probe needs a conductor in order to penetrate the skin and reach the deeper layers of tissue. The gel is ideal for this.

Treating a knee injury.

It’s important to move the probe constantly to avoid “hammering” the same tissues for a long period of time. Tracing small circles allows the vibrations to spread through the tissue without causing damage.

An ultrasound machine can produce waves in a constant or a pulsatile flow. A constant flow of ultrasonic waves produces a greater thermal effect, while a pulsatile flow helps to create a greater mechanical effect.

Using ultrasound in physiotherapy

So, in what situations can we use heat and high-frequency vibrations to treat patients? Let’s take a look at some of the conditions ultrasound therapy is most commonly used to treat.

  • Inflammation: ultrasound therapy is an effective treatment for conditions that cause inflammation. The effect of the ultrasonic waves increases blood flow to the target area, promoting healing. If the inflammation is no longer acute, increasing blood flow encourages the body to replace any old or damaged cells. Ultrasound therapy can, therefore, be used to treat conditions such as tendinitis, bursitis, and capsulitis, among others.
  • Sprains: as we’ve already mentioned, tendons are some of the best ultrasound-absorbing tissues, making injuries where the tendon has been overstretched and damaged good candidates for this kind of treatment.
  • Healing and scarring: ultrasound treatment may also speed up the healing process by increasing cell metabolism, and promoting recovery.

As yet, there’s not enough scientific evidence to confirm whether or not ultrasound therapy is an effective treatment for musculoskeletal injuries. While some recommend ultrasound therapy for problems such as muscle cramps, its effectiveness has not yet been proven. In any case, physiotherapists already have a range of proven treatment options to offer patients.

Using ultrasound therapy to treat injuries.


Iontophoresis treatment consists of using ultrasound to deliver drugs into the patient’s subcutaneous tissue. Instead of applying a conductive gel to the skin, this technique involves applying the drugs directly to the skin in gel form, allowing for better absorption. The results achieved will depend on the drugs used.

Ultrasound therapy – contraindications and precautions

Because it uses high-frequency vibrations, there are certain precautions you have to take when using ultrasound in physiotherapy. Firstly, an ultrasound isn’t suitable for use on tumors, or any tissue that might bleed.

Similarly, it’s not recommended if the patient is suffering from an infection, or from conditions such as deep vein thrombosis, arteriosclerosis, or similar circulatory issues. Finally, it’s important to be careful when using it on patients with metal implants or pacemakers. It’s important to move the probe frequently, taking particular care with bony areas.

Ultrasound therapy and its place in physiotherapy

Taking all of this into account, it seems that ultrasound therapy has an important role to play in physiotherapy. While further research is still required, its effect on inflamed tissues and chronic conditions seems promising. However, as always, it’s important to know the risks, as it can be a rather aggressive form of treatment.

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All cited sources were thoroughly reviewed by our team to ensure their quality, reliability, currency, and validity. The bibliography of this article was considered reliable and of academic or scientific accuracy.

  • Wen‐Chung Tsai, Jong-Hwei S. Pang, Chih-Chin Hsu, et al. Ultrasound stimulation of types I and III collagen expression of tendon cell and upregulation of transforming growth factor β. Journal of Orthopaedic Research. Volume 24, Issue 6, Pages 1310-1316. 2006.
  • Gail ter Haar. Therapeutic ultrasound. European Journal of Ultrasound. Volume 9, Issue 1, Pages 3-9. 1999.
  • Gail ter Haar. Therapeutic applications of ultrasound. Progress in Biophysics and Molecular Biology. Volume 93, Issues 1–3, Pages 111-129. 2007.

The contents of this publication are written for informational purposes. At no time do they facilitate or replace the diagnoses, treatments, or recommendations of a professional. Consult your trusted specialist if you have any doubts and seek their approval before beginning any procedure.