there's something to the idea, imho.
i've been unable to gig for a couple months. just before christmas i had my right shoulder joint replaced. it's similar to a hip replacement: the bearing surfaces of a ball-in-socket joint are cut out and replacement parts put in. usually it's a matter of six weeks to recover, and you're back in action--but mine was a hard case. the bones had been severely damaged by osteoarthritis (put it off too long), so the operation ran twice as long as usual. the surgeon has to move to main nerve in the arm (the brachial plexus) off to the side to get at the bones, and unfortunately mine went dead from being stretched that long. when i came out of the anesthetic the arm was completely paralyzed with no feeling anywhere. the bad news was that i couldn't do anything at all on the bass, but the good news was that nerves do come back from this sort of injury, with time.
my band subbed for me on bass, but i went down the gigs to do my vocal parts and keep in touch. sure missed being able to play...
i found in idle moments during the days the nerves were slowly regenerating i was imagining some tunes and some new lines to play, picturing how they'd lay on the fingerboard and hearing how they'd sound. (ear training is an ongoing project for me; very valuable.)
so last night i played my first gig since the middle of december. i've gotten enough nerve function back in the arm to hack my way through a night. (i'd told the BL i could only bring my B game, but said he'd be glad to have that! the sub wasn't working out all that well.)
so when the tunes i'd been imagining came up, i played the lines i'd been practicing in my head--and they worked pretty well. fun!
this experience convinced me there's benefit to this musical version of the _visualization_ technique many athletes use, yep.