First of all, let us see two exercises of the opening of the groin in order to prepare backward flexions. These two exercises are done on the wall, and they are also two variations of Bhujangasana.
The first exercise is also called “Rope # 1″ in Iyengar Yoga (where the use of a support for the groin is not compulsory). In both cases represented on the upper sketches – the groins are supported:
In the first case (left drawing) by a bolster placed on a chair,
In the second (right-hand drawing) the strap is placed at the level of the hollow of the groins. Pressing gives information to the muscle and allows it to relax so that it opens up more. The first sub-variation makes it possible to open the frontal groins and the chest (almost) passively, since one “hangs” from the strings.
The second variation opens the groins and strongly urges the extensor muscles of the back to lift the unsupported chest.
2 – Bhujangasana with chair
(or how to understand the circular legs to torso movements)
What is remarkable in this asana is that the legs are completely on the ground which produces a large surface of grounding as there are few or none in other back flexions. Here we learn the ABC of the legs, trunk and the pelvis work in the back bending, a work that will be all the easier to understand that the important points have a grounded support.
What are the actions which help provide space to the lumbar?
a. You need to work on your feet and legs:
The small toe will be pressed more closely towards the carpet (if you choose to hold your feet together you will leave the big toes in contact). This has the effect of moving the heels outwards and this pressure combined with the activation of the thigh muscles supporting the internal rotation initiated by the correct work of the feet has the effect of giving space to the buttock bones and thus to the lumbar (QED).
b. Through the work of the pelvis (Tadasana effect).
Here, as in Tadasana, the pelvic girdle makes a circular motion, the pubis, and the outer hips press the ground while the tail bone descends.