With all the cyber forum posts about thumbs up, thumbs down, early or late, advanced or delayed, the ROTATIONAL dimension of the shortest, and most problematic finger is often overlooked, and because of miss-directed attention, the clunky thumb brigade marches relentlessly through countless arpeggios and scales.
But change is possible!
During the course of this evening’s piano lesson, an adult student had an awakening about her thumb as she successfully rotated it through the G Major arpeggio on descent. With a detached (non-legato) approach she managed a picture perfect maneuver, replayed below in three silent motion frames. (with my intro)
Bonus video: G Major arpeggio in legato and Staccato–working on smoothing out thumb shifts
In Summary: The thumb should be relaxed, pliant, flexible and feather light.
The Relaxed Thumb