Doesn't the consideration of thumb under vs. thumb over apply to arpeggios in the same way as to scales, i.e., it's primarily a question of the speed at which they're played?

Steven

I recommend you to do the "thumb under" technique, as it will make the arpeggios sound more legato. I'm not really familiar with the ABRSM examiners but I believe they will take off marks for that.

A few months ago I probably would have disagreed, but I recently realised how important it is to do standard thumb under first. Skipping does not build support in the fingers or flexibility in the thumb. I've discovered that one of the reasons for a weak right hand 4th finger (and limited range of motion in the thumb) is the fact I always flicked across, rather than ever joining.

A good exercise is to hold onto the thumb (while under) at the same time as the third or fourth. If you squeeze very lightly in an inward direction, the keys push you back out. If the flexibility is inadequate for comfort, this will improve it very quickly. Soon the position will be more easily obtained. However, if you already feel fully stretched when doing this with arpeggio positions, it's probably best to begin with a more comfortable interval, so you're not straining the limits of your motion early on. Once you reach comfort, you can either flick across at speed or get a comfortable legato connection at a slow tempo. It really is important to have the ability to manage either equally well. Flicking will usually start to occur of it's own accord (when movingat speed) but traditional thumb under can only be more willfully mastered.