The force of a punch results from three factors—(1) force, (2) acceleration, and (3) wave.

When I received my self-defense training in the Marines, I was told to always step into a punch if you couldn’t avoid the blow…

This argument comes up quite often at gatherings where the tactics of the sweet science are discussed. It doesn’t matter if the guests are fight fans or even physicists. There are strong opinions on both sides of this debate.

I am going to present some facts to you, minus the equations and formulas, so Homeland Security doesn’t think we are talking about building a dirty bomb. You are going to hear about mass (the quantity of matter), velocity (the rate and direction of motion), acceleration (the rate and change of velocity), and wave (a disturbance that travels through a medium). Don’t let these words intimidate you. I will try to dumb it down for all of us, just keep reading!

When I received my self-defense training in the Marines, I was told to always step into a punch if you couldn’t avoid the blow. This was the conventional wisdom back in the day. I took it as gospel, since it came from my senior drill instructor. He was considered to be a god during those twelve weeks of boot camp.

Some physicists try to explain the delivery of a punch to the head this way.

1. All agree the best way to avoid damage to your brain is to avoid the punch in the first place. If you can’t avoid it, some believe you should step into it early. Others feel you should roll with the punch and go in the same direction as the high velocity blow, to reduce the impact. Similar to how you catch a baseball barehanded.

2. The mass behind a punch is time-dependent. The longer the wave, the harder the impact of the mass.

3. If you consciously step into a punch, your neck and shoulder muscles will automatically tighten up in anticipation of the blow. Your skull will also drop downward as you step in, which will cause you to receive the blow high on the forehead. Angle you head toward the attacking arm. The skull is the hardest bone in the body. The impact will move through the skull, down through your tight muscles and dissipate throughout the body with less chance of concussion to the brain.

4. If you take the impact moving back from the punch, the muscles are loose and the shockwave stays in the impact area, which can increase chance of a concussion. Also, if you lean back, the head comes up and you expose your jaw rather than your skull to the punch. The jaw is of a thinner bone, which can break or cause more severe damage to the brain.

Sir Isaac Newton’s 2nd and 3rd Laws of Motion was published in 1697. They describe the body and the forces acting upon it. But you have to be an Einstein to understand them. But here goes…

2nd Law of Motion—The acceleration of a body is directly proportional to, and in the same direction as, the net force acting on the body, and inversely proportional to its mass.

3nd Law of Motion—When one body exerts a force on a second body, the second body simultaneously exerts a force equal in magnitude and opposite in direction to that of the first body.

Maybe we shouldn’t have gone there? Newton’s Laws give me a headache. Let’s hear from someone who has field tested these theories. No laboratory, chalkboard or white lab coats here.

Martin Ziegler has a 4th degree black belt in Taekwondo, as well as a black belt in Karate and Judo. He was a combat military self-defense instructor in the German Army. He is forty-six years old with a body like a steel spring. He has been teaching martial arts for decades. If you ever stumble into a bar fight, Martin is the guy you want to be there and have your back.

I sat down with him one night at our gym to finally put to rest the debate on whether stepping into a punch is a credible defensive move. Here is some of what he told me.

“There are various theories on this tactic. The force of a punch results from three factors—force, acceleration and wave. Stepping into a punch or a kick is always dangerous because the punch will already have 70 to 80% of its power. Shorten the wave by stepping in and deflect the punch, before it reaches its full acceleration of 100%. The key factors again are stepping in, deflection of the punch and response. It is much easier to deflect (block) a punch and respond if you get there early (stepping in). You also get to immediately respond with your own punch at 100% force. If you wait for the punch to come to you, it is harder to deflect. You could possibly break your arm in the deflection. It will land on you at 100% force, rather than the reduced 70 to 80% early on.

“It is very common in self-defense to step into a punch. If you see someone ready to attack you, go into him to minimize the force. The game is reaction. You want to avoid, you want to be able to step in, deflect and respond. You want to step in while the punch is in development. This way you reduce it’s force. Boxers often lean back from the waist to avoid a punch. Leaning back from the waist puts a fighter off balance. If the punch lands at that time, it could result in a knockdown or KO. The best thing to do is to jump back in this situation, so you land in a stable position on both feet, then attack. While martial arts students do this, boxers do not.”

I then asked Martin about short punching. After all, these punches have a short wave and less time for velocity and acceleration to build up, yet they can land with terrific force. So how does that work? Is it the exception that proves the rule? Jack Dempsey was said to have been the best short puncher in the business. What was Jack’s secret?

Martin responded: “The secret of the short punch is that it is a straight punch. The shortest distance between two points is a straight line. Power, full force, focus and straight and intense alignment all have to be there. Everything has to line up. The full force of the entire body is in the punch. A short, straight punch of two to five inches is all that is needed. The key is to have the weight of your whole body behind the punch.”

Having heard from physicists with advanced degrees, they still can’t agree about stepping into a punch.

Martin Ziegler has little doubt that it works for him. From what he explained and demonstrated, I’ll have to go with his take on things. Stepping into a punch… It does reduce the force of a blow. The move is fact not fiction.

Author’s Note: Martin Ziegler holds two Master Degrees, one in Mechanical Engineering and the other in Economics.