There was a book on learning piano playing that I must have seen near 50 years ago.
In there there was a detailed description of some all-time great -- I think Godowski.

The story as I remember it ran thus:

Godowski was practising for 14 hours a day for two years straight.
One day when he got up from the piano he was so utterly fatigued that he could not hold his arms to the piano.  In that moment he discovered a quality of touch that was super-gentle non-struggling, non-violent. And that touch became his hallmark then on.

So:
- Is it Godowski I am remembering?
- And does anyone have a reference to this?