@laurie, I started with wrist vibrato for many years, and then first year of university I worked on arm. So now I pick and choose which to use depending on what I’m playing. The movement does come from the wrist, the idea of bending the wrist being bad comes from the collapsed position. I’ve seen a few people try wrist vibrato the wrong way, where they move the forearm forward, fingers go back, the wrist collapses, and then move back to the regular position. This is very wrong, does not sound like vibrato, and puts the player at risk for injury. Instead, the correct way is where the wrist bends forward, then back to the regular position. It’s kind of like waving to yourself.