As I learned in my classes, if someone comes at you to attack you, and you take a tough stance, with a rigid position, you are most likely going to be bowled over. Picture yourself standing rigid, with your feet shoulder-width apart, parallel and planted. When your opponent hits you in the shoulder, you will fall over like a 2 by 4. If, however, you soften your stance, anticipate their energy and provide no resistance, the story changes. Now, picture yourself standing with your feet parallel and apart, but one a little behind the other. When your opponent hits you, rather than resisting, you let them push your shoulder back, and taken by surprise, with nothing to push against, your opponent will actually be caught off guard and will be the one who falls past you. It works.
I have shared this with clients who have taken the approach into the office or the boardroom - figuratively I believe! When faced with someone who is aggressively opposing something or promoting something, they have tried offering little resistance, to find that it takes the energy out of the "opponent's" approach, quickly diffusing a possibly volatile situation and allowing cooler heads to prevail.