Head position on dismounts from High Bar
When discussing the head position of any skill I believe it is very important to first ask what the implications are from all standpoints of where the head is positioned? It is vital that you consider all implications because the majority of coaches would never ask a gymnast to throw their head back when perform a somersault from the High Bar yet the majority of dismounts from High Bar at high levels are all performed with the head thrown back off release. We have to ask why this is, and what circumstances would benefit from this process?....
The head is the most dominant factor through which movement occurs. Think of it this way, stand up from your computer right now and turn around and walk to the end of your room. I guarantee 100% of you reading this first lifted your head up, then stood up, you then turned your head and proceeded to turn around. The head drives everything. You want forward rotation? You drive your head downwards. You want backward rotation? You drive you head backwards.
Now with those important concepts understood, lets look at what the implications are of the head position off the bar and which one is the most effective to choose for a single flyway from the high bar.
Head position #1 - Head in (pressing the chin to the chest): You want to flip backwards from the bar and begin to press your chin downwards onto your chest to begin flipping backwards. The natural progression of driving your chin downwards is to facilitate forward rotation. Therefore, not ideal when a gymnast would like to release the bar and rotate 240 - 270 degrees to a landing position, can still be performed and in lots of circumstances is. A head in position does decrease the chances that the agle of the shoulders will remain open, something very vital to the safety of dismounting backwards.
Head position #2 - Head out (exposing the neck): You want to begin flipping backwards of the bar so naturally you would like to drive your head back. However, there is a very dangerous aspect of this that a beginning gymnasts may misinterpret. By driving the head backwards the chances of the shoulder angle decreasing and the 'pulling in' effect occuring are greatly increased. It is important to tell gymnasts that throwing the head backwards should be reduced or increasing the shoulder angle should be achieved to not increase the chances of coming close to the bar upon release.
Head position #3 - Neutral (neither exposing the neck or pressing the chin to the chest): To flip effectively in this position a strong kick from the bar in a hollow position, with the correct timing involved is sufficient enough to create 240 - 270 degrees of rotation to a stand position. It is ideal becuase it is a healthy balance between te two positions, decreasing the problem of closing the shoulders, and allowing the body to naturally flip in the backwards direction upon release.
My preference is Head position #3 for the majorty of athletes because of its relation to tackling the two problems of dismounting, how much rotation is necessary with the correct amount height/distance from the bar. However, do keep in mind that drive the head backwards actually increases rotation of flipping velocity as the head drives backwards leading the body through the flip. A single dismount from the horizontal bar is not necessary for this concept though.