One of the greatest benefits of ultrasound therapy is, that it is thought to reduce the healing time of certain soft tissue injuries. As the ultrasound waves pass from the treatment head into the skin they cause the vibration of the surrounding tissues, particularly those that contain collagen. This increased vibration leads to the production of heat within the tissue. In most cases this cannot be felt by the patient themselves. 

The increase in temperature may cause an increase in the extensibility of structures such as ligaments, tendons, scar tissue and fibrous joint capsules. In addition, heating may also help to reduce pain and muscle spasm and promote the healing process.

Ultrasound may also stimulate the production of more collagen which is the main protein component in soft tissue such as tendons and ligaments. Hence ultrasound may accelerate the proliferative phase of tissue healing. It is thought to improve the extensibility of mature collagen and so can have a positive effect to on fibrous scar tissue which may form after an injury.