Starting my practice was... difficult. I began with Surya Namaskara A (sun salutation). That lasted for 3 rounds. Initially, I wanted to complete 3 of A and 3 of B and then move on to the fundamental poses. I was feeling frisky before I started the practice. Frisky didn't last long though. I ended up quitting after 3 A's and 2 B's.
It felt like my uterus was being squeezed every time I folded forward. It didn't matter how wide I spread my legs to fold either. I'm not sure if it was the position my son was in or what, but it definitely made practice difficult and even painful at some points. I was infuriated for a moment because I wanted to go further, but as I dropped back into Child's Pose I realized I was upset for no reason. You can't force yourself to do things because it would only make things worse in the long run. So, as I sat in Child's Pose I breathed and tried to quiet the pain. I completed a few rounds of Cat and Cow and then completed the last round of Surya B and the closing poses.
Maehle's chapter on Kumbhaka was quite interesting to read over. There was a lot of information that was gone over and needs to be digested. Another good over read probably wouldn't hurt either.
Kumbhaka, or breath retention, isn't merely holding ones breath. Anyone can attempt to hold their breath and elongate the time one is able to hold their breath. A good example would be free divers, those people can hold their breaths for a really long time as they try to go deeper into the ocean. What separates Kumbhaka from a person holding their breath is the end result.
"When kumbhaka exceeds 10 seconds, the bandhas, i.e. Jalandhara, Mula and Uddiyana bandha, need to be applied . . . The length of all inhalations, retentions and exhalations must be counted to such an extent that their ratio to each other follows precisely a predetermined count (such as 1:4:2) and a predetermined number of rounds is practised" (Maehle 57).
I can't begin to attempt to explain all that this man has included in his book on pranayama and kumbhaka, at least to the extent that he has. However, in this chapter Maehle describes the three lengths of kumbhaka (short, medium and EXTRA long). They are all goals that a yogi attempts to master in their quest to raise Kundalini as well as increase prana (life force).
The most interesting thing I found in this chapter was a story that Maehle tells of his time ascending the Himalayas with an Indian Shaivite sadhu (religious ascetic). It is a great example of a use of kumbhaka as a way to ignite heat (or angi=fire) within the body. The sadhu would use kumbhaka as a way to heat their bodies in the crisp cool mountain air. It was necessary for them to maintain their warmth because they were not able to enter into any human made habitations (crazy right?).
Maehle states, "after a while, not being bound by a religious vow I forsook my pride and joined the locals inside their house in the vicinity of a smouldering campfire. Despite this – and my expensive Western-made doona sleeping bag – I was woken by the freezing cold. Sheepishly I ventured out into the open, half expecting to find my sadhu either frozen to an ice block or at least suffering from pneumonia. I was surprised to find that he was absolutely fine. He told me he was used to keeping his body temperature stable overnight by use of kumbhaka" (Maehle 62).
The longer one practices kumbhaka the warmer the body becomes, and thereby allowing one to withstand extreme cold temperatures with little clothing. It is amazing what the human body can withstand with so little.
Claudia does a much better explanation on her blog for this particular chapter (and for the others too actually). If you want to read further, you can access her blog on kumbhaka here. OR you can read along with both of us and share your own thoughts by purchasing the book :).