Piano Forum

I mainly use my forearm rotation to hit the octaves, but this seems to build up tension, which I'm sure Liszt had none of while playing this piece.

I visualize an axis from elbow to fingertips (fictional finger 2.5 between forefinger and middle). You rotate around this axis that pivots off the elbow point. The forearm should be laxed and uses just enough energy to carry the wrist to desired point. Then rotate your thumb and pinky about the wrist like a pellet drum but in an extremely flat arc (flattened rainbow) as to glide. Those fingers should be laxed as well and hit those 50-55 gram keys with sufficient force and not more. Understanding of the piano action mechanism and knowing when to stop adding force is probably critical in achieving smoothness and speed. The faster you go seems like the smaller the chance to relax however. Also, striking heavier on one end seems to help.

Some mental construct of the fixed distance would also help since it is a constant that ascends and descends. One of the motion seems to be easier to achieve than the other. If you have small hands you depend on solid proprioception to precisely hit (or jump to) those keys without looking. Larger hands minimizes the guestimate and would have an advantage in this exercise.