Playing with Eka Pada Raja Kapotanasana
One of the best posture to warm up the lower back prior to a stronger back bend practice is Bujangasana (the cobra posture), which can be done as part of the classic Surya Namaskar sequence, or on it own. The action of the hips and legs in this posture is virtually the same as on the back leg in EPRK making it a particularly suitable warm up for it.
Another posture which is most useful to prepare for EPRK is Ardha Hanumanasana, demonstrated below. The hip work is the same as for EPRK but there's no presure on the shoulders and the pressure on the lower back is greatly reduced, so one can take time to soften the hips into it.
If the hips are very stiff, it can be helpful to prop up the buttock on the foward leg side with a block or a blanket, as demonstrated below. People who need this type of support should not attempt the full posture, but work on the preliminary posture until they are confortable in it without support.
One of the difficulties is getting the shoulder and arm into position (there's a knack to it). This can be made much easier by using a belt, as demonstrated below.
Final PoseOnce the postures above are mastered (which can be judged by the quality of the breathing), one can tackle the full posture. This is how to get into it:
From Ado Muka Svanasana (downward facing dog), transfer the weight onto the left foot and move the right foot forward behind the left hand. Let the right knee come down onto the floor behind the right hand and soften the hips downwards. Lift the chest and move the shoulders back.
Then bend the right knee and catch the foot with the right hand, with the fingers on top of the foot and the thumb nearer to the heel a,nd rotate the elbow outwards then upwards to bring the arm and shoulder into position (this is where the knack is). Get a good grip on the right foot, secure your balance, and then reach back with your left hand also, holding the foot with both hands. Keep lifting the chest. TIlt the head back and bring the right foot forward to touch the head.
Enjoy, you're now in the full posutre.
Once you have mastered the basic posture, EPRK offers many opportunities for creative asana practice. Some possibilities are demonstrated below. In "Light on yoga", BKS Iyengar demonstrates a number of variations.
Counter posesA strong backebending posture like EPRK should be followed by a strong forward bend as a counter pose. Janu Sirsasana is perfectly suitable, as both postures are asymetrical, but any of the leg behind the head postures, or even kurmasana, could also be used.
Moving onEka Pada Raja Kapotasana is an excellent preparation for Natarajasana which adds to the shoulder and lower back work the extra difficulty of balancing on one leg :).