Today, I noticed that my left pinky is collapsing (not quite locking, like one would do a knee, but flattening out) when I stop the string with it. It isn't anything I've noticed before, so there may be some laziness creeping in. The middle knuckle isn't bent as much as it should be. It's never given me any pain, and the stopped notes are solid as those stopped with the index and middle, but I'd like to deal with it before it causes trouble down the road. Anyone haev any exercises to help keep the arch over all four LH fingers? Thanks in advance.