How to destroy blocks thrown my Van Rutah ?

Hi everyone ! I finally arrived at the point where I have to get on Sidon's back to access the divine beast. The thing is, when the beast is throwing blocks at me, I can't seem to destroy them. I can only use cinetis to stop them moving but they eventually break free and I still get hit. I saw someone saying you should destroy them, but I can't find how to. Maybe I didn't unlock the power to do so ?