These three basic concepts in FMA that I try to teach to my students and get them to understand all the time. These apply to sticks knives and empty hands.
1st concept- get out of the way! If you are not at the point of impact you do not get hit, simple right, you see this in boxing, FMA and Kung Fu. In boxing its called Bobbing and weaving, in FMA it is called Elastiko or Rubber Bando, in Kung Fu you see this in Drunkin Man style. I have even seen this in Tai Chi. Kids do this in ducking and dodging in games like dodge ball and prisoner. You will see this in the foot work of all three methods.
2nd concept- block! If you can not get out of the way you need to block or parry! This means you failed to follow concept 1. You can block, by being stationary, meeting the force or re-direction the force. This is common in all kinds of weapon fighting and hand to hand method. In boxing you see them slipping a punch, in FMA you see the parry and counter strike, even in Western Fencing you see the parry thrust movement.
3rd concept The armor takes it. This only works if you are fighting with some kind of armor like WEKAF style full contact. The problem with this is Kinetic energy is still transferred through it. The force goes out in a ring of energy. I have seen guys sparring with just helmet cups and lacrosse gloves take shot to the hand and have it break, I have seen guys get KO by getting shot straight to the helmet. I have seen in boxing guys with boxing helmet get their bells run hard. Again Concepts 1 &2 are most important to avoid damage. If the armor has to take it make it a glancing blow instead of a dead shot or a head on collision.
Just some thoughts for the day!