Pete, To my surprise, the problem hasn't really been bad habits. I never use too much pressure; if I can't hit a note without jamming the mouthpiece into my face I won't go for it. I also breathe correctly, and don't create too much tension in my throat, face, etc. The core of the problem really is just chop weakness, due purely to overdoing it in the upper register (it's not a permanent thing, as I can rebuild my range for short periods of time before overdoing it accidentally). That being said, you have the right idea on practice. For the past few days after recovering from my last mini-injury I've been doing just that - practicing range (not overdoing it this time ) and mixing in things like clarke studies and playing soft ballads to relax while still building. I'm making sure to take breaks when needed, using the "Rest as long as you play" idea for each set of exercises I do (lip slurs, arpeggios for range, soft stuff, improv being the main "sets" of exercises). Balanced practice seems to be working great for me!