I’ve been working on playing my scales and things faster. My goal with scales and arpeggios is to play them with both hands sixteenth notes at quarter note = 132 BPM. If you don’t have a sense of how fast that is, it’s pretty fast.
After the first five minutes or so, my hands are tired and beginning to cramp. I don’t like to stop and rest, so usually I will switch back to playing triplets at 132, and make sure I’m breathing regularly and not holding any unnecessary tension.
I practice scales on my Casio Celviano digital piano, which has a graded hammer action keyboard. I try to work the lower octaves, where the keys are especially heavy, in order to really strengthen my fingers.
I listen for any irregularities in the tone, and try to correct them without slowing down. At this tempo, often I try to send messages to my hand and hope they respond to my wishes- they are moving too fast for me to consciously analyze the movement.
By the time I switch over to the organ and start practicing jazz stuff, my hands are hot to the touch!