Practicing-Making Music from The Heart. She offers an approach to practicing that releases tensions and allows greater and more natural musical expression. The key to lower back pain is stronger abs. Make sure your knees slope down and are lower than your hips. I always make sure my car seats are so adjusted also.
Lower knees puts stress on the back.
I also have just started seriously practicing each and every day and always wear a brace. Braces are a necessity for me most days and definitely when playing the piano. Even at that, sometimes I still get a little pain. I found the best brace - and I have many, for playing is one of those navy blue ones sold for horse riding with a pad in the back. I use the widest one they make since the narrower ones roll up I find.