From the net... The noise from a kiai is said to arise from the
hara or
dantien: it involves the abdominal muscles and diaphragm and
should not be sounded merely from the throat.[2]
As well as the above, the kiai can be used to:
- prime oneself for combat, by "amping up."
- protect the upper body from a strike by providing an escape route for exhaled air.
- protect the lower body by rapidly contracting the transverse abdominals and other core muscles, shielding the internal organs.
- provide solid abdominal support for striking techniques.
- startle and demoralize actual or potential adversaries ? especially at close quarters, or if previously unobserved.
[FONT="]The proper use of kiaijutsu involves concentrating on the use of one's
ki more than it does shouting. A sound is just an audible indication of good kiai (aligned body structure, focused intent, and good breathing). Kiai can be a silent;
[1] coordination of breath with activity. A relaxed and powerful exhalation can add power to movement. [/FONT]