10 years ago by
A Pianist
What the thumb does in a scale depends on what speed you play it at. But as I always say, we are looking for the greatest variety of actions, to create the most global technique possible, so the more things the thumb can do, the better.
At high speeds it doesn't go under at all, the hand just undulate/shifts to the next position, there is an actual break in the line of notes, but they are going so fast you don't hear it. Slow motion photography of concert pianists shows this to be true; interestingly enough, the pianists filmed ALL said that they WERE passing the thumb under. Thus the presence of the neuological image of passing the thumb, even when it's not happening in reality, seems to be a key component of having the scale work.
At low speeds, really work to make your thumb as active as possible. Do all the exercises from the thumb chapter of the DVD, especially the horizontal translation of the thumb. See how much this can empower its participation in scale work.
Whether or not you pass the thumb under, if you stand your four fingers on the board, your thumb should be able to reach all the way under your hand to touch your fifth finger, then wave out to the other side until it's pointing straight away from your hand. Do this vigorously several times, and then play a scale without thinking and see if the vestiges of the neurological image of the new thumb movement had an affect on your scale.
All the best,
AFF