I have a question concerning head movement with the Jab. With professional boxing, I notice that most boxers lean their head off to the right when and pivot with their hip when they Jab, like this:

http://www.youtube.com/watch?v=IBnBcGst5CI

I understand that it adds power, but to me, it seems that it leaves you pretty open for a Cross. It also would seem that it takes longer to throw a Cross if you are doing a weight shift with a Jab as opposed to a "straight" Jab and a Cross. Sounds confusing, so here is a video of a straight 1-2 with no hip twists or head movement:

http://www.youtube.com/watch?v=PO4oa6DbrI8

Thoughts?