I've been trying long and hard to find a term to decsribe what I have: trembling, shuddering, shaking, quivering. "Ratcheting" might be another one. Almost all of my muscles are doing it, most especially my quads and my wrist extensors, but only during relaxation, not contraction. I broke my brain and my search engine trying to look it up online because I couldn't find a word for it. Just lately, (I mean today) I've noticed my hands and especially my thumbs visibly shaking as I extend my arms from a tightly flexed position. I think it might be the brachioradialis doing it but I'm not sure. Is this common in BFS?