Acupressure [from Latin acus "needle" (see acuity) + pressure (n.)] is an alternative medicine technique similar in principle to acupuncture. It is based on the concept of life energy which flows through "meridians" in the body. In treatment, physical pressure is applied to acupuncture points with the aim of clearing blockages in these meridians. Pressure may be applied by hand, by elbow, or with various devices.
Some medical studies have suggested that acupressure may be effective at helping manage nausea and vomiting, for helping lower back pain, tension headaches, stomach ache, among other things, although such studies have been found to have a high likelihood of bias. Like many alternative medicines, it may benefit from a placebo effect.
Acupoints used in treatment may or may not be in the same area of the body as the targeted symptom. The traditional Chinese medicine (TCM) theory for the selection of such points and their effectiveness is that they work by stimulating the meridian system to bring about relief by rebalancing yin, yang and qi (also spelled "chi").
Many East Asian martial arts also make extensive study and use of acupressure for self-defense and health purposes, (chin na, tui na). The points or combinations of points are said to be used to manipulate or incapacitate an opponent. Also, martial artists regularly massage their own acupressure points in routines to remove supposed blockages from their own meridians, claiming to thereby enhance their circulation and flexibility and keeping the points "soft" or less vulnerable to an attack.