Repeated notes always can be controlled as a group of repeated notes controlled by a continus dropping pattern of the hand. Like in the Ravel's Alborado del Graciaco when the Rh first comes across the repeated notes it is clearly defined as groups of three. These groups of three notes have a paticular sound associated with them, different to groups of 2 repeated notes or any other. Our fingers are kept close together, they all extend and raise as the first finger drops onto the first note of the group, then the rest of the fingers repeating that note continue to drop down with gravity. If we try to strike the note with individual finger movements we are just going to tire ourselves out very fast and have a hard time controlling the sound produced.
The piano you are on definatly effects how easy/hard it is to repeat notes. I find electric pianos with no touch sensitivity and instant key sping back action are the easiest instruments to repeat notes.
I agree with the second part. As far as the first part, I am generally opposed to trying to work out such problems with intensely detailed physiological methods, so I would like to offer some alternatives.
But first about the second part, the instrument matters so much that Kristian Zimerman said that much Ravel is only possible on a piano that has been mechanically modified to suit the composer's needs. Repeated notes are a definite element in his music, so do not assume that Thibaudet's piano has not been adjusted in some way - it could very well have been! That doesn't take anything away from him of course. It could be the nature of the beast as Zimerman said.
Repeated notes come in different shapes and forms. The first movement of the Tempest Sonata for instance has many repeated notes. The trick there I discovered, is to not let the key come all the way up. This way you achieve the slur effect and the repeated note at a very fast tempo.
For multiple repeated notes on the same key, whcih the Tempest does not feature, I recommend obviously switching fingers, but more than that, to pretend you are pllaying a five-finger pattern, or four-finger, whatever. If I repeated G five times, 5-4-3-2-1, I pretend to be playign, G-A-B-C-D. It is a mental image that has helped me overcome internal difficulties to repeated notes, and most if not all difficulties are internal.
Walter Ramsey