Are there any strictly technical exercises / drills that have been really beneficial for improving your jazz playing and technique? I'm not talking about learning solos etc - I spend most of my practice time working on language by transcribing and learning tunes, which involves lots of studying, listening, analysis, slow repetitive playing, internalisation etc, but I really need some practice ideas for times when I just want to give my brain a rest and focus on the physical aspects of playing. Let's say you've just spent 8 hours working, and your brain is tired, you don't feel like either dissecting a 270bpm Coltrane solo or working on the artistic side of your playing, but you still want to practice and have a bass workout. So apart from scale runs, is there anything else that you run on a regular basis which has helped you become a better jazz musician? Is it even possible to switch off the creative side of your brain and focus purely on the physical aspects of playing?