Hi there.
What do you think about playing with arm's tension and strong pressure on the keyboard? Try it either in pp and ff, pushing the key very slowly but with great tension of fingers and arms...and listen.. what a sound!.
Dan
Dead end.
Besides all physical problems and injuries it leads to, it contradicts the main principle of performance--first, you have to have an image of the sound, only after that produce it--not the other way around.
What happens, is that your brain has an image, then it send an impulse into your finger tip, you take the sound, listen how it matches your image, and then your brain sends impulse of correction, or feedback. If there is
ANY tension on the way, no matter whether it is in your neck, arms, even in finger joints, it blocks away these impulses, and the whole mechanism of playing gets completely disbalanced. The only tension (I'd say intensity) can be between finger tip and the key, for certain sound effect, but it relies not on physical tension, but the weight of your arm you put into the key.
Tension and musical intensity are two completely different things, and I think this is where you get confused. Try to listen to a recording of your favorite piece, tense your body and see if you can enjoy the piece? I don't think so. You will see that in order to absorb all the beauty of the music, all your body needs to be completely relaxed--sit comfortably, etc.
I don't see how reproducing music is different.