hey, ladies! great comments on the whole yoga thing. I've never been to a class, so I wouldn't really know what to expect from one, except what I've read. Basically, there are so many different types of yoga, and so many different teachers, that there likely is a yoga for everyone!
That said, if you want to avoid the trying a bazillion classes just to find the one that's right for you, do like Kim and I both did. Pick up a Rodney Yee video and start with that. I bought a book, too, and very soon was integrating poses (asanas) from the book in addition to those on the video. 3 years later, I do yoga anywhere from once a week to every day, depending on what else is going on that week, I don't follow a video or anything - I've put together a sequence that works for me. Between those two starting out steps (the vid and the book) and buying Yoga Journal every month (great magazine, and many articles and asana instructions are posted on their site, too http://www.yogajournal.com/ ) I'm enjoying yoga tons!!
Yes, my balance and flexibility have improved, without question. I've also noticed that I'm generally a bit less clumsy and forgetful (I don't suffer as much from "where did I put that thing down that I just had in my hand?" as I used to) and I can focus better and have greater patience with myself. Great things on the mountain bike trail!! Most rides end with a very short sequence of warrior and pigeon poses to stretch hip flexors, quads, glutes, hams, etc, and, if I miss doing that I'm definitely much stiffer!!
As for the pain in the lower back concept - it's important to not cause your body pain, especially sharp pain! Low back compression is often caused by tight hip flexors, which are usually present in those of us who have sit-down jobs and those of us who ride bikes!! The best teachers, videos, books, etc, will also offer variations in poses that help you learn the best form and get you from not much flexibility to being able to do the asana completely.
Hey, one pose (peacock) tooks me 2 years to accomplish! Now I can do it in lotus position, too....
As for the breathing....the closest I get is simply trying to take longer slower belly breaths, which also helps while biking. And as for the spiritual aspects....don't stress it. You might be surprised and achieve some new insights, but I wouldn't worry much about it. Start with the purely physical aspects of the pose and really think deeply about that while you're doing and learning the poses....that process of paying close attention to your body position and your body's feedback can be helpful in so many ways!!
Hope that all helps!
Namaste,
~T~