I'm trying to preserve precision after playing high. Let me explain, yesterday I was strengthening high G. A couple minutes in, I'm playing clearly and loudly. I meander just below it chromatically, and then back on G. I repeat this for about 5 minutes. Again, focusing on clarity and loudness. I took about a 5 minute break, then I had horrible problems playing middle staff and below. I lost precision--I couldn't consistently differentiate those lower notes. For example, I'd play middle G, but instead hit the C above (a bit embarrassing and frustrating). An hour later, I was fine though.
Any suggestions on how I can work on this (besides extended recovery times)?