It is not surprising that an old woman can make your arm hurt with a piece of wood. I have always been skeptical of arkane explanations for phenomena that are more easily explained obviously. Occam's Razor, etc. So I would default to the explanation that most obviously fits the facts. Further, a thick elbow sleeve will wad up on the flexion side of the elbow, thus mechanically "jacking" the joint apart under loaded flexion. I am assuming you have read the book and therefore know that the first manipulation in a grip problem is to adjust the width. Perhaps a video is in order.