I didn’t watch the video, but agree with the others regarding the value of shooting at a vertical line. Folks have been doing that as a walk back tuning method for 30-some years that I can remember, and somewhere along the line it morphed into a form training exercise. I consider it kind of a hybrid blank bale method.
With blank bale, all you are doing is ingraining the feeling of the shot into your subconscious. It’s a valuable tool, but where it falls short for me is the lack of quantifiable results to determine consistency. Targets don’t lie; if you group well you are shooting consistently. Blank bale offers no such feedback.
Vertical misses (up and down) are caused by one set of problems; horizontal another. What shooting at a vertical or horizontal line allows you to do is isolate one set of variables at a time. If I’m having problems with vertical head position, high and low grip pressure (heeling the grip), maintaining my bow arm through the shot (dropping my arm), or sliding down out of my anchor, I shoot at a horizontal line. If I’m having problems with balanced expansion through the shot, grip torque, plucking the string, or string blur (horizontal head position), I shoot at a vertical line. It’s no coincidence that the target backstop in my basement had a big giant + on it in blue painters tape.
