this is mostly just a compilation of blog posts that i find to be helpful from Katy Bowman of Aligned and Well. I put it together for a student who has been having some back pain. Hopefully you will find it helpful as well.

here is some info on how to release the pelvis from that tucking position and strengthen from there. note that if you read down and follow the comments you can learn even more from them.
this is a great one on finding a healthier standing position
http://www.katysays.com/mind-your-pelvis/

part way through this article she talks about finding "neutral pelvis"
http://www.katysays.com/neutral-pelvis/

this article and the next are all on learning to do Healthy Squats!!
http://www.katysays.com/you-dont-know-squat/

http://www.katysays.com/you-still-dont-know-squat/

this article is an interview with Katy Bowman is on kegels and the issue with them, i like how she talks about WHAT THEY DO to the pelvic floor and the pulling on the sacrum which has a delumbarizing (is that even a word?? i mean reducing the lumbar curve) effect as well.

http://mamasweat.blogspot.ca/2010/05/pelvic-floor-party-kegels-are-not.html

it's a fair amount of reading. but Katy is pretty hilarious i have been following her for years and i am now in her training course, and as a yogi have found it to be super helpful to fill out the stuff that yoga just doesn't cover.