First off, flexing a bow backwards is prolly the quickest ways to break a bow I've seen. There seems to be some confusion with string follow and set. String follow is the amount the tips follow the string after a bow is unbraced, this relaxes with time. Set is compression damage to the cells of the wood, many causes of this, wet wood, uneven tiller. Oh yeah, there are a lot better ways to brace a bow than in the video.