Upper-arm Forearm Rotation

Another important warning is, never to substitute upper-arm rotation when rotation of the forearm is required. Understand the distinction, that it is possible to bring your hand into playing position by raising the upper arm and elbow sideways and outwards with the hand upon the keyboard. Thus the sockets of the two forearm bones at the elbow are themselves turned outwards, and brought almost perpendicularly one over the other. The natural movement of forearm-rotation should be used to set the keys in motion on the keyboard.

If you are not quite sure of this distinction between upper and fore-arm rotation, refer to the following "test exercise", which ensures that you are executing the correct movement. Fold your arm in front of your chest and balance it nicely and freely. Now rotate the forearm, while it is in front of you, as easily and freely as you would when executing a tremolo. With the arm thus bent at right angles, you are bound to use only forearm rotation, and the upper-arm rotation is not employed for the time being. Next, stretch your whole arm straight out in front of you, and again, with the forearm only, execute your free and easy tremolo movements. And now, instead of this comfortable forearm rotation, try to substitute a twisting of the whole arm using the shoulder-socket upper-arm rotation. Although you may partially succeed in doing this, you will still find that the forearm rotation is easier and natural. Now apply the rotatory tremolo of the forearm to the keyboard itself by means of any two fingers. Carefully eliminate any technique that involves upper-arm rotation when generating tone at the piano.