Ultrasound is a therapeutic modality that has been used by physiotherapists since the 1940s. Ultrasound is applied by using a round-headed wand or probe that is put in direct contact with the patient's skin.

Ultrasound can produce many effects other than just the potential heating effect. It has been shown to cause increases in tissue relaxation, local blood flow, and scar tissue breakdown. The effect of the increase in local blood flow can be used to help reduce local swelling and chronic inflammation.