During intermediate and advanced practice of rapid breathing and alternate nostril breathing techniques, the breath is held after full inhalation. With rapid breathing, the breath is held between groups of rapid breaths for just a few seconds initially and, after more practice, for as long as comfortable. With alternate nostril breathing, each completed inhalation is held for a few seconds initially and gradually extended to a period four times as long as the inhalation time--the time ratios for inhalation, breath hold, and exhalation being 1:4:2 in the final stage.
In more advanced practices, the breath may also be suspended after exhalation. The mind is focused inward during breath holding and may concentrate on a particular area of the body such as the heart or forehead regions.
During breath suspension, the head is bent forward with the chin pressing against the hollow of the throat, and the anal sphincter muscles are usually contracted. These techniques are called the chin lock (Jalandhra Bandha) and root lock (Moola Bandha) respectively.
The abdominal lock (Uddiyana Bandha) is applied in more advanced breath holding, but is performed as an independent practice first. In the initial practice, the person stands, bending forward slightly with the arms resting on slightly bent knees. As air is exhaled, the abdominal muscles are drawn back and up toward the spine, creating a hollow in the abdomen.
After maximum exhalation, the chin lock is applied and the chest is expanded, creating inhalation pressure against the closed air way, which further draws the abdominal region upward. When used with other breathing practices, the abdominal lock is initially used with exhalation. Later, chest expansion and abdominal muscle contraction are applied with breath holding after full inhalation, although inhalation pressure, of course, reduces as lung inflation increase.
