Anyone have experience with their dog’s leg shaking during or after exercise?

Reddit wouldn’t let me upload a video so here’s a Imgur link: Video of her leg shakes She’s had these to some extent since she was 4 months old. Now she’s three and we still have no idea. I’ve asked two vets but never seem to get a clear answer. I’ve read it may have to do with allergies. We’ve been on apoquel for five-ish month with no change.

Any advice?