Random thought: the feeling I get from these exercises is very similar to the spine-tingles I get when listening to an amazing piece of music. Are these somehow related?
I meant to reply to this before but was short on time, and I just remembered it. I would like to comment on this from the perspective of a musician, rather than speaking directly on how energy and music are related.
When a good musician plays, he does not need to "play" his instrument. Instead, he simply relaxes, and rides the music as it flows through him, as his body moves effortlessly and naturally almost on its own. Like a surfer on a good wave, the musician does not control his music, he rides it.
Using the terms that have been taught in this group, it is a lot like simply relaxing into wuwei or void, and just letting the music happen. The music doesn't need to be rigorously controlled, the instrument does not need to be ruthlessly focused on. This musician has trained for many hours, probably for years, and understands his instrument and his music--he simply needs to relax and let it come out.
When a good musician plays like this, he puts a lot of energy and spirit into his music, and it gains that "it" factor that empty music does not have. That is why when we listen to it, if we relax and empty ourselves in void as well, we can resonate with it and feel the power and spirit of the musician that performed it. This is one of the major differences between good music and empty music. Empty music does not have the spirit of the musician behind it, it is just a nice string of sound.
The discussion of vibrations and even the metaphysical aspects of music is a long topic that I am not particularly interested in right now, but the above is my experience as both a musician and a fan of good music. And even besides that I think it is not entirely untrue to say that it is easy to get into a meditative state when getting absorbed in good music, and thus some people might experience energy movement just as they would in meditation.