I'm looking for suggestions on how to improve my Alberti bass. When I play it fast, I can only go for a little while before my LH gets tight and cramped. The things I've tried so far are (1) treating it as a parallel set, playing the chord as a chord, ie infinitely fast, and then slowing down - that helped a lot for fast scales but not for the Alberti bass (2) practicing very slowly, focusing on keeping the fingers close to the keys all the time and paying attention to the feeling of the release of the key as well as the touch (3) using dotted rhythms (4) trying to relax as much as possible while playing it fast, thinking stuff like "Oh, what Ho, look at my hand over there playing the piano, how nice, la dee da," (5) just playing the Alberti passages in question at a tempo that doesn't cause cramping, over and over (6) concentrating on wrist rotation, without going overboard with it, I hope.
My teacher says just keep at it. That's fine, I'm patient. But I wonder if anyone has suggestions for other approaches to getting to a point where I can play long passages with a fast Alberi bass.