(31) Thumb, Most Versatile Finger, Power Thumb

The thumb is the most versatile finger; it lets us play scales, arpeggios, and wide chords. It has four major ways to move down (play a note):

(1) finger motion : with the hand motionless, play the thumb with only finger motion, by pivoting each finger at the knuckle (the "thumb knuckle" is at the wrist),
(2) wrist motion : with the forearm motionless and rigid fingers, play the thumb with wrist motion only,
(3) arm motion : with the fingers and wrist rigid, play the thumb by swinging the entire forearm down. This motion originates at the shoulder, and by
(4) Forearm rotation ( (21) Forearm Rotation ).

Practice each of these motions separately, eliminating all stress. First, practice each slowly, with large, exaggerated motion. Then increase speed by decreasing the motion. This exercise will reveal which is your fastest motion. Speed can be further increased by combining the motions because, when combined, smaller individual motions will be needed to accomplish the same key drop. Separating each motion is difficult at first, because we usually combine most of them for any thumb motion, which is why it is important to practice each motion separately.

Play with the tip of the thumb, not the joint (of the nail phalange); this will enable the thumb to slide and the wrist to be raised, thus reducing the chances of the other fingers accidentally hitting unintended notes. Playing with the tip makes the thumb as long as possible, which is needed because it is the shortest finger. This also increases the range and speed of the thumb movement; that is, for the same thumb movement, the tip moves farther and faster than the joint.

There are two thumb positions: weak and power. Place both hands on the keys, straight in front, the thumb nails facing each other; this is the weak position. The thumbnails are almost vertical to the keyboard, and the tips of the thumbs are bent slightly towards the fingers so that they are almost parallel to the fingers. This position is useful for slow or easy passages.

For technically difficult material, especially when power is needed, use the power thumb position: with both hands on the keyboard, extend the thumbs straight out, so that the thumbnails now face upwards towards your face (LH thumb on G3, RH thumb on G4). This position enables rapid play, makes optimum use of forearm rotation, allows complete relaxation, and utilizes the strongest muscles in the thumb: those powerful muscles that are used to push thumb tacks into a wall. Applying force in the weak position can cause pain and injury, not only to thumb muscles, but also elsewhere.

The power thumb position is attained by raising the wrist so that you play closer to the palm-side tip of the thumb. This automatically causes the thumb to point down and engages the strong muscles of the thumb. The weak thumb position is attained by lowering the wrist so that the hand is level with the forearm: you are now playing more with the side of the thumb. In general, try the weak thumb position first, and if this is inadequate, gradually add the strong position. Thus the use of weak/strong thumb is analogous to TU/TO; they are not generally used in their extreme positions, but somewhere in between. Most of us think of the thumb as the strongest finger; however, even the pinky can overpower the thumb in its weak position, especially at high speeds. The strengths of the thumb and pinky can be balanced by a proper choice of the weak/power thumb positions, in applications such as the octave tremolo.