Pilots do this too: "chair flying," rehearsing procedures in your head before the real flight. It works well for checklists, but chair flying a workout still sounds funny to me.
Similarly, a headset can "read your thoughts" (inner voice) by detecting subtle activations in the facial muscles. A student at MIT constructed such a headset about ten years ago:
It can legitimately help you drive a lap faster in e.g qualifying.
During longer periods away from flying I will spend a few days prior to the next flight mentally chair flying normal procedures.
I do think there’s some level of experience necessary for this to be beneficial though. Chair flying a plane I've never flown isn’t likely to be very productive without feedback from an experienced pilot. I would imagine the same is true for a couch potato trying to imagine a difficult squat set.