For maximum effectiveness, it is necessary to lengthen the spine while turning. If the spine is not elongated, the twist will be uneven. Coordinate the twisting movement with the breath. Lift the spine on an inhalation, and turn on an exhalation. Hold, take a few normal breaths in the new position, and then gradually increase the twist. Check to see that both shoulders are level. Allow the head to turn naturally. Forcing the head to rotate too far will strain the neck muscles.
During pregnancy twists should be performed gently to prevent overstretching. The majority of the twist will come from the neck, upper back, and shoulders. The neck can rotate approximately 45 to 50 degrees, and the upper back about 35 degrees. The lower back, designed mainly for side bending and forward and backward movement, is capable of only about 5 degrees of rotation.
The most vulnerable area is the sacroiliac joint, the joint where the sacrum joins the hip bone. This joint is designed for support, and it is supposed to remain stable. The sacroiliac joint is connected by strong ligaments. During pregnancy, the hormone relaxin loosens these ligaments. If twists are done forcibly, the sacroiliac joint may become unstable. This can happen on either side of the sacrum and may cause pain.