Forearm tension

[adooskii]

I've been playing the piano for roughly a year and a half, mostly self-taught but I've started taking lessons with a teacher every few months since the beginning of the year. I recently bought myself a digital piano with weighted keys and I've noticed tension building up in my right forearm, to the point where playing faster passages and trills is much more challenging then when I feel no tension at all. I believe the culprit to be the bad habit I have to lock up my wrist and arm when playing faster passages. It seems I simply rely on finger action to hit the keys. My question is the following: how do I break this bad habit? I've read up about how you should be using your whole body to play the piano but I am having a hard time applying the concept to my playing. I've also explored the Taubman approach, but it seems to be a hit or miss in most cases. Is there any exercises that you can recommend me to help me overcome this challenge?

[anacrusis]

I believe the culprit to be the bad habit I have to lock up my wrist and arm when playing faster passages.

Sounds likely to me!

Regarding using your whole body, I also find it hard to actively do something to implement this idea. I find more success by thinking that if I relax my body, it'll know what to do. You can maybe experiment with approaching the piano in a very relaxed manner and investigate how you can tell your body to remain relaxed when you press keys. It can be tricky to figure out and I'd say it's much easier if you can get a teacher.