Nauli is mentioned in various yogic scriptures but with little detail. In the Gherand Samhita it says: “Vigorously rotate the abdomen from side to side. This practice eliminates all types of disease and increases the digestive fire.” (v. 1:53) Nothing more is explained. From the description given it is completely impossible for a beginner to learn and practise nauli. Personal guidance is necessary. In the Hatha Yoga Pradipika it says: “Bending the shoulders forwards, the abdomen should be rotated from right to left and then left to right. This practice is called nauli by yogis. Nauli removes abdominal ailments, increases the digestive fire and brings happiness. This is the greatest practice of hatha yoga.” (v. 11:33, 34) Again the description is valid, but too brief for learning nauli. These short verses in the scriptures are intended more as a method of remembrance than as instruction. Instructions had to be learned directly from the guru.
In nauli various muscles are utilized in the abdomen, back, legs, arms, etc. However, the practice is primarily concerned with contraction of the rectus abdominii muscles. These are two long vertical muscles located in front of the abdomen. The top ends are fixed under the centre of the ribcage near the diaphragm and the bottom ends are fixed at the pubic bone just above the genital region. The two muscles are wider at the top than the bottom.
The rectus abdominii function in conjunction with other abdominal muscles. The main ones are called the external and internal obliques and the transverse abdominii. These muscles, together with the rectus abdominii, are arranged in sheets in such a way as to give maximum strength and control. They protect the inner abdominal organs. When they are insufficient then hernia can result. These muscles also contract and massage the internal organs and aid one another in the process of micturition (passing of urine), defecation, vomiting and also childbirth in women.
It is these muscles that are directly manipulated during the practice of nauli.
Before attempting nauli you should master the practices of agnisar kriya4 and uddiyana bandha5. Without mastering these two preparatory techniques you will find nauli difficult, if not impossible.
Stand with the feet a little less than one meter apart. Bend the knees slightly. Lean forwards. Place the hands firmly on the thighs just above the knees. The fingers can point inwards or outwards; choose the position that you find from experience to give the greatest contraction of the abdominal muscles during nauli. The arms should be straight throughout the whole practice. Bend the head forwards and gaze at the abdomen. This position of the body is clearly illustrated.
Summary of full practice
Time and practice are required in order to master nauli. Also, one should progressively develop control over the abdominal muscles. For this reason we have divided nauli into two stages, as follows.