To make up for my lack of knowledge on all things yoga, I’ve been borrowing related books from the National Library and just reading through them before I go to bed. One book that I’ve found extremely useful is “Ashtanga Yoga – Practice & Philosophy” by Gregor Maehle. It has detailed explanations of each and every asana in the primary series and really helps the reader to appreciate the logic behind the design and sequencing of the poses. I found it a very good complement for our classes and would highly encourage you to borrow it if you have a chance (there are several copies available at the libraries).
One of the more accessible poses in the Ashtanga primary series is Janu Sirsasana. I am almost certain that you will find a variation of this pose done in non-yoga fitness classes and even by the casual athlete. As an athlete but not-quite-yogi myself, I’ve always found it curious as to why we have so many versions of what seems to be a simple pose. Well, it appears that the mechanics behind Janu Sirsasana A, B, and C are actually a little different *gasp*
Let’s start with Janu Sirsasana A. This is essentially a combination of Paschimottasana on one leg and Baddha Konasana on the other leg. This means that the sole of the foot of the bent leg needs to be facing upwards, so that the knee is protected as we fold forward into the pose. We also want to try to place the heel as close to the groin of the same leg, so that the entire unit (thigh+knee+calf+foot) can move easily as a single unit, again protecting the knee. As positioned, the femur of the bent leg is laterally rotated. As we fold forward, this femur would start to rotate medially. If we had not positioned our foot correctly before folding (i.e. most beginners), this process could strain the knee.
Janu Sirsasana B is slightly different. Instead of a plantar flexed foot as in A, the foot is of the bent leg is dorsiflexed. This is actually the more natural (i.e. wrong) positioning of the foot used by beginners (i.e. myself) attempting Janu Sirsasana A. For B though, we are going to scoot our butt forward so we’re sitting on the sole (not the heel only; I apologize to those in this morning’s class). Due to the angle of the sole, it’s actually easier to fold forward (for me, at least) and you would notice that unlike before, the femur starts to rotate laterally as you do so. It feels almost like a weird form of Vajrasana on the bent leg as we fold forward.
In Janu Sirsasana C, both the foot and the toes of the bent leg are flexed. It is easier to get the foot in position first, and then scoot forward so that the heel is pressing into the groin of the straight leg. The femur will start to rotate medially as this happens and actually, you will notice that the angle between the thighs in Janu Sirsasana C is naturally smaller than in Janu Sirsasana A. This is anatomically correct. Again, we will proceed to fold forward but unlike in Janu Sirsasana B, we will continue to medially rotate the femur of the bent leg as we deepen the pose.
In terms of purpose and benefits, we can now see that each Janu Sirsasana variant opens the hips slightly differently as the poses are deepened. Also for Janu Sirsasana B, the heel presses into the you-know-what of guys and is therefore therapeutic for the male reproductive system. Correspondingly, Janu Sirsasana C, where the heel presses into the uterus, is especially therapeutic for the female reproductive system.
Isn’t it amazing how the Ashtanga primary series was developed! It’s a pity how commercial yoga classes are getting shorter and shorter so teachers have less and less time to go into such precious details. Let us all hope that this depth of knowledge isn’t lost as time passes.