If you have limited flexibility, once a week is probably not enough no matter what you choose to do - especially if you fall back into the movement patterns that create inflexibility in the first place. You know, the harmful things most of us are required to do too much of, things like, oh, sitting for instance!
Yoga is great for the mind as you know, core strength, flexibility, and creating the mind/muscle "connection" or awareness. It wasn't until I started doing Yoga that I became aware of my bad posture without having to see it in a mirror. It also made me aware of where I was carrying stress. I started noticing that even while lying in bed watching TV my right trap would be tense. I'd never noticed that before. I must have walked around for years with one shoulder up around my ears.
You're not supposed to be able to start out doing all the asanas. Nor
should you be able to even after years of practice! You gotta start at the beginning and that's gonna be a different place for everyone. And, I don't know about you but even after I gained flexibility I was having difficulties because I lacked the upper body strength required for many things I wanted to try. It took me over a year to get into a back bend - coming from the floor. When I finally got up there I nearly hurt myself because I was so damn excited.
