Ischemia means a lack of blood supply, with associated tissue irritation and congestion. Ischemic compression is used in both Shiatsu and trigger point work. The purpose of ischemic compression is to deliberately increase the blockage of blood to an area so that, upon release, there will be a resurgence of blood. This washes away waste products, supplies necessary oxygen and helps the affected tissue to heal. This increase of blood flow to the area is called a hyperemia.
"To apply ischemic compression to a trigger point, the relaxed muscle is stretched to the verge of discomfort. Initially, a thumb (or strong finger) is pressed directly on the TP to create tolerably painful (7 to 8 on a client pain scale of 10), sustained pressure. Treatment is useless if the patient tenses the muscles and so protects the TP from pressure. As the discomfort tends to abate, pressure is gradually increased by adding a thumb or finger from the other hand, as necessary, for reinforcement. This process is continued up to 1 min. with as much as 20 or 30m lb. of pressure. If TP tenderness persists, the procedure can be repeated, preferably after a hot pack and active range of motion.’" Travell, Janet, Myofascial Pain and Dysfunction, The Trigger point manual, v1.
Following treatment it is valuable to gently stretch the area to help the muscle "remember" its full length.
The first treatment should be conservative, lasting one or two minutes only, followed by a day of rest for the treated part. The treatment is resumed on alternate days until the pain abates and full usage is returned, usually within 3 to 10 sessions. Appropriate application of ice following treatment is recommended.