This is a bodywork procedure that uses suction force against the skin to reduce pain. Suction is achieved by using plastic or glass cups, which helps to increase circulation, break up adhesion and siphon fresh blood into affected tissue. It is also effective in increasing muscle firing in muscles that are deficient. Cups are placed stationary at the site of pain, or moved up and down the muscles. Since the involved tissue binds with normal tissue, it develops a blood supply. As restrictions are released from healthy tissue, bruising may occur, especially in treating chronic conditions. Some areas of the body that have a very rich blood supply may produce more bruising. An increase in soreness and discomfort is not uncommon after the first treatment session and is most often a positive sign that restrictions have been released. Soreness is usually minimized after 48 to 72 hours and can be controlled with ice and stretching.