Did full primary this morning. Having made the switch (i.e. split) to doing second only and doing primary just once a week for a few weeks now, I now notice some interesting things about primary:
(1) Primary is actually more challenging on the muscular-skeletal level. Well, actually, second is also very challenging on the muscular-skeletal level: All those backbends in second definitely work the muscles of the front-body and the ribcage, and Karandavasana... well, need I say more? :-) But I guess what I'm trying to say is that primary works the gross muscular-skeletal structure more exclusively, especially with all those vinyasas. And I sweat way more in primary than in second. Which might also mean that primary is more challenging on the cardio-vascular level. But the interesting thing is that even though I sweat more in primary and feel my gross muscular-skeletal structure being worked more, I am actually able to maintain a fairly even breath throughout all of primary. Whereas I am always super-winded when I exit Karandavasana in second. So it is possible for something to work your cardio-vascular system less (at least if measured solely in terms of amount of perspiration) and yet demand more on the level of the breath. Interesting, don't you think?
(2) Having done second only for the rest of the week, I have forgotten how much harder it is to go into finishing backbends from primary than from second. In second, one's back is always more or less opened from having done Kapotasana, even if Karandavasana tends to have a shoulder-tightening effect. So the finishing backbends are quite accessible.
The same cannot be said about going into the finishing backbends from primary. Even though I went into the finishing backbends the Kino way today (i.e. do one Setu Bandhasana (Bridge Posture), then one set of three Urdhva Dhanurasanas, then another set of three UDs. During the third UD of the second set, try to walk the hands towards the heels and catch them. And then try to stand up from there.), my shoulders (or mid-back, I'm not entirely sure) still felt very tight. During the third UD of the second set, I walked my hands towards my heels, but my shoulders were so tight that my elbows collapsed to the mat before my hands could touch my heels, and I had to lie back down. I had to do a third set of three UDs. And it was only on the third UD of this third set that I finally managed to touch my hands to my heels and stand up. There is a silver lining to this "cloud", though: As a result of all this hard work, my quads were worked really good.
(3) At the end of practice, I looked at the time. Despite my backbend drama, I still managed to finish the whole thing in less than an hour and a half. It's nice to know that switching to second only has not diminished my stamina in primary :-)