20 minutes on the treadmill at the Y today (again paying close attention to form, which along with the fact that the treadmill is boring made it feel ten times harder), not one twinge. Making progress! I'd better just ease back into it and keep working on glute strength/activation and stretching the TFL. I definitely feel the coordination is not as good on the left side (the one that had the problem) as the right, as far as the glutes working when they are supposed to and the TFL not trying to pick up the slack. Anyone have any other tips for fixing that or ideas of how long it takes?