How Does Ultrasound Therapy Work?
Ultrasound produces high frequency sound waves as a result of synthetic crystals expanding and contracting in the metal treatment head of the machine when an electrical current is introduced. These sound waves are absorbed into the skin. Additionally, ultrasound has both thermal and non thermal effects. The thermal effect is where tissues (particularly those that contain collagen) produce heat from the increased vibration and this increase in temperature helps to reduce swelling and increase the extensibility of ligaments, tendons, scar tissue and fibrous joint capsules. The non-thermal effect is used more for healing wounds as the ultrasound promotes new connective tissue growth and accelerates the repair. This is achieved by the ultrasound attracting more mast cells to the site of the injury, thus accelerating the normal resolution time of the inflammatory process and causing an increase in blood flow (hence it is not recommended to use ultrasound immediately after injury).
A special ultrasound gel is placed on the skin to ensure maximum contact between the head and the surface of the skin as sound waves dissipate on contact with air. This gel also provides a medium through which the sound waves can travel.
Ultrasound therapy can be beneficial for:
Chronic inflammation or swelling
Inflammation & swelling
Restricted range of motion