I might make this the subject of a new thread at some point, but I will try to deal with it briefly here. The eternal debate between those who say we should pull and those who say we should row and those who say it is dangerous to try to do either one reveals a huge blank spot in our understanding of the vault. How can it be that so many elite vaulters and coaches could disagree so much on such a basic issue?
Here is what I think is going on. The major muscle used to pull on the pole is not the biceps. Anyone who tries to do a chin up on a moving pole is in big trouble, which is why many coaches teach that any pulling on the pole is dangerous, and given that this is their concept of "pulling," they are right to do so. However, if anyone tries to do a Bubka on a high bar without a pulling motion, they will find that it is impossible. The arms have to be involved in the process or the best an athlete can do is hinge at the waist and get their ankles instead of their hips to the bar.
I believe that the major muscle involved in getting the right motion started is the anterior serratus, which holds the scapula to the thoracic wall. This muscle can only do one thing and that is to rotate the shoulder both forwards and down. If you stand with your ams extended up over your head and push your shoulders up towards your ears as far as you can and then pull them down as far as you can in a sort of reverse shrug, you will see that the shoulders have to move both down and forwards. An athlete with a proper concept of the swing can focus on a forward, rowing motion and the shoulders must also pull down. Another athlete can focus on a downward, pulling motion and the shoulders must also row forwards. Each is describing the same movement, although in entirely different terms. The athlete's concept does not matter so much, as long as the anterior serratus fires at the right time and in such a way as to help add speed and power to the swing. I, personally, believe that the focus should be on more of a pulling motion, but I don't have time to go into that now.
I realize that this may not be exactly what is going on, and my detailed knowledge of anatomy is basic at best, but I think I am on the right track here. Anyone with a better understanding of these structures and how they move through a range of motion want to chime in?