This is a video of my forearm and elbow picking blend motion, or at least in this video the picking hand part. In the video I play a tremolo for a while and then, annoyingly off camera with the fretting hand, play a run notes which start on an upstroke to show it’s not only elbow motion on its own. You’ll see I bend my wrist to the right but I don’t think there is any wrist motion involved in the picking itself although I may be using the wrist to help to angle across the various strings.