Ultrasound therapy uses sound waves of a high frequency to affect tissue in many beneficial ways. During the treatment a gel substance is first applied to the skin of the injured area to provide a medium for the sound waves to travel through. A specialized wand is used to transmit the sound energy into the tissue. This causes a vibration of the surrounding tissue increasing the internal temperature of deeper structures like torn muscles, tendons and ligaments, fibrous joint capsules and other scar tissue. The increased heat causes an increase in blood flow to the site of the injury, which is important in bringing in vital nutrients that repair the injured tissue, but also to remove any waste products. The sound energy increases the extensibility of these structures by stimulating new collagen growth, and making old collagen more pliable. Thus reduces pain and muscle spasms and promotes healing.