Source: http://www.sonima.com/yoga/uddiyana-bandha/
The Sanskrit word bandha is generally considered to mean “lock” but more literally “to bind” or “to hold captive.” In hatha yoga, bandhas are physical contractions that give structural support to the body including the organs in the pelvis, abdomen, and spine. These locks become especially important in keeping the body healthy during a vigorous and physically demanding practice because they engage the tissue surrounding the core. When engaged in conjunction with pranayama (breath work) and kumbhaka (breath retention), bandhas stop the movement of prana (the vital life force, or energy). According to the Hatha Yoga Pradipika, a classic Sanskrit manual on hatha yoga, when this force stops moving, the mind stops moving as well.
Uddiyana means “to rise up” or “fly.” In the practice of uddiyana bandha, also known as the abdominal lock, the abdominal wall is firmed and lifted. The tension created when working with the uddiyana bandha is a form of “tensegrity,” the relationship between tension and compression. When the core is engaged (tension) there is a natural upward flow (compression) of energy that gives the necessary support to the abdominal organs and spine. On a more subtle and esoteric level, uddiyana bandha fans the agni, or element of fire that is most highly concentrated at the navel. Strengthening this fire aids in purifying the body’s subtle channels, or nadis. This purification pro…