In boxing, you can build the bridge with fancy footwork, or any art.Why do you want to build a "bridge" for?
How many times that you can knock your opponent down by your 1st punch? 99% of the time, your opponent will block your 1st punch. If you know that your 1st punch will be blocked most of the time, you don't want to commit 100% on your 1st punch. You may just want to commit 30% of your force into it. Since you know that your opponent will block it, you try to take advantage on his blocking.
- You knock on the door,
- when your opponent open that door,
- you then enter.
That "door knocking" in
- boxing, it's called jab/jabs.
- CMA, it's called "build bridge".