One of my students around 2006 was a police officer and a member of his department's S.W.A.T. team.
During our Xingyi classes, we trained the fist postures, how to use them in self-defense, and we worked on taking ground.
In Xingyi, the goal is to drive through your opponent like a bowling ball through bowling pins, and when the attack is over, you are standing on his ground. It is physically and psychologically damaging.
So my student responded to a standoff situation one day. The perp was across the living room. At the right moment, my student lunged across the room using the same technique in this video and he took the perp down using Pi Chuan (Splitting Palm).
While he was being cuffed, the perp looked up and asked, "How did you do that so fast?"
Nobody expects you to take ground, keep your energy down and deliver power over seven to ten feet. When I was in my forties, I could take ground over a distance of eleven feet. Now, at age 68, I can't do that. But the drill in this video is very helpful if you want to develop this skill.
You can improve your ability to take distance. If you learn to deliver power from eight to ten feet away, you will plow through somebody who is four or five feet away like hitting them with a bus.
I am wearing a hand protector in this video because, being on blood thinners after developing clots in my lung six months ago, I can't exactly risk internal bleeding in my fist when doing bare-knuckle board breaks. That's why I am wearing a pad. I leave the bare-knuckle stuff to the young guys.