Coach, should one also shrug the shoulders (or allow them to shrug as the weight goes up) during overhead presses, or only during horizontal presses?
I personnally drop my shoulders down when the bar is just pass my forehead and push my head forward between my arms while the bar travels backover the middle of my head. This gives more stabilility to my upper back while allowing me to keep my back straight and not arching my lower back.
Exact same thing i do. I find it much harder to stabilize my upper body when keeping my shoulders completely shrugged through the entire movement.
What exactly are the scapulae doing during these two movements?
What do you mean? Apart from acting as a base for the arms? BUT this is not self-answering, since when shrugging you get upward rotation of the scapula and as common sense tells me, this means you can lift your arms more without impingement.
Personally, i've found just pinching my shoulder blades together works the best. No shrug or the back and down powerlifting style.
I seen Mike Tuchscherer talking about it. He recommended the style for raw benching.
That pretty much answers my question.