Piano Forum

This is a funny thing - because I do not believe not having a teacher always means you're going to have bad technique. One thing we do when learning with teachers is mimic their behaviours because their way gets results for them when it doesn't necessarily work for us. We can see many professional pianists all playing and sounding differently.

That aside, your wrists aren't moving enough I think which is probably why your arms are moving more.

I see you move your whole arm forwards and your wrist remains very high. High wrists are, from what I understand, required mostly when playing octaves and octaves at fast speeds.

The interesting and positive thing you can take from this is that you have already identified a potential issue and so you have to investigate ways to resolve this.

Without a teacher your options are the internet to find others with similar issues to resolve, or self investigation, try playing passages differently, try different sounds such as staccato, clinging-style legato and see how you body changes and see if that loosens up your hands and wrist.

Looking at some other videos it seems like you're trying to play from your arms too much

at 2.50 here

Maybe try the passage slowly - you need to work on keeping your arm and wrist still and moving the fingers, that's not to say use only the fingers, but the main work ultimately comes from them.

Your left hand and wrist is also looking very high lower them wrists! and have them flexible