Ultrasound therapy obviously has a correlation  to ultrasound: acoustic waves that vibrate at a frequency not audible to the human ear, i.e. 20000 Hertz. Their use in a therapeutic setting is possible because the ultrasound penetrates the biological system and releases a wave. This is precisely why ultrasound therapy is a widely used treatment in physiotherapy; it is a mechanical heat therapy that brings benefits through a high-frequency cellular and intracellular massage action. The sound, in fact, has elastic characteristics that generate an oscillating movement. This vibration produces a series of compressions and rarefactions that spreads in the form of a sound wave. Its propagation speed depends above all on the characteristics and temperature of the body being treated. Therefore, the tissues reached by the ultrasound in turn vibrate, producing heat. This is why ultrasound therapy has an analgesic, antiphlogistic, muscle-decontracting and local metabolism-stimulating therapeutic action.

The use of ultrasound therapy is used exclusively in orthopaedic and some rheumatic conditions, mainly due to the analgesic function of ultrasound.

Precisely because this therapy varies the pressure in the tissues, it generates a compression and decompression phenomena that produces heat through friction. The effect obtained is similar to that of a massage, which promotes tissue fluid exchange with anti-oedemigenous effects, ideal for reducing the onset of oedema following trauma. In addition, ultrasound heals tissues.

The thermal effects generated by ultrasound therapy are part of some forms of thermotherapy that can boost local metabolism, reactivate circulation, and reduce muscle spasms and contractures.

Ultrasound therapy is performed by means of an electro-medical ultrasound device. Conductive gel is applied to its probe to enable a better transmission of sound vibrations. The probe is moved in a slow rotary motion over the part to be treated. A session usually lasts between 10 and 15 minutes.

It is widely used for its analgesic effect in the treatment of knee or ankle pain reduction following muscle injuries.

The therapy can be used in two ways: with direct contact and with indirect contact. Direct contact (see procedure above) is the most commonly used. Indirect contact, on the other hand, is carried out in water by immersing the area to be treated in a basin and keeping the probe about 1 cm away from the skin. This is a less common method, but essential when dealing with irregular areas that are difficult to treat directly such as elbows, hands or malleoli.

As we have seen, ultrasound therapy is particularly used in physiotherapy, since ultrasound generates an effect that is very reminiscent of a massage; this sensation, combined with the thermal effect generated by the pulsation, deeply warms the injured area and facilitates cellular and intracellular exchanges.

The benefits it brings have analgesic, anti-inflammatory, muscle-decontracting and metabolism-stimulating effects. It is no coincidence that this type of therapy is very popular among athletes.

Another advantage of ultrasound therapy is the fact that it is a deductible health treatment, but must be prescribed by a doctor and performed in specialised centres. There are also portable ultrasound therapy devices, but their use cannot be carried out without the presence of a specialist who personally handles the application.

Under no circumstances should ultrasound be used in the cardiac area, on the cephalic region and on testicles and ovaries as there is a risk of severe damage. Extra caution must be exercised when performing ultrasound therapy on the spine of patients who have had laminectomies as a result of spinal cord damage.

Other people at risk are undoubtedly patients with prostheses or with metal fragments inside the body, who have problems with varicose veins, wear pacemakers or other electronic medical devices. People who have suffered haemorrhaging and pregnant women should also abstain from this type of therapy.