In the movie Rocky IV, Ivan Drago registers a 2,150-psi punch. That seems unrealistic to me, and yet I’m hearing Internet rumors about MMA fighters and boxers coming close to that number. Is it possible to throw a punch that hard? What would that sort of power do to someone’s face? — Dave
The Rocky movies are fiction, Dave. That tells you pretty much all you need to know. But let me add some details.
First we need to clear up the difference between force and pressure. Force is what causes something to accelerate, e.g., a fighter’s head in the direction of a thrown punch. In the U.S. force is normally measured in pounds. Pressure is force per unit of contact area, commonly expressed in pounds per square inch (psi). When researchers study punching ability they usually focus on force rather than pressure, since the pressure varies as the contact area expands on impact.
With that in mind, let’s look at the research:
— A study of seven Olympic boxers in weight classes ranging from flyweight to super heavyweight showed a range of 447 to 1,066 pounds of peak punching force. Energy transferred from punch to target varied widely depending on how heavy the boxers’ hands and gloves were, how fast they punched, and how rigidly they held their wrists. The three flyweights, interestingly, delivered more oomph than all but the two super heavyweights.
— A study of 70 boxers found elite-level fighters could punch with an average of 776 pounds of force. Another study of 23 boxers showed elite fighters were able to punch more than twice as hard as novices, the hardest hitter generating almost 1,300 pounds of force.
— An oft-cited 1985 study of Frank Bruno, who’d go on to be WBC heavyweight champ, showed he could punch with a force of 920 pounds in the lab. Researchers extrapolated that to a real-life blow of 1,420 pounds, enough to accelerate his opponent’s head at a rate of 53 g — that is, 53 times the force of gravity.
— Martial arts punches generally involve much less force than those in boxing. A study of 12 karate black belts showed so-called reverse punches delivered an average force of 325 pounds, with the strongest measuring 412 pounds. Short-range power punches averaged 178 pounds. Another study found martial artists needed 687 pounds of force to break a concrete slab 1.5 inches thick. One early researcher estimated karate strikes could reach 1,500 pounds, but that figure was an outlier.
If a punch thrown by Rocky IV villain Ivan Drago is supposed to measure 2,150 psi and his glove’s impact area is something like four square inches, he’d be exerting a force of 8,600 pounds, or more than four tons. Based on the professional literature, no boxer in real life comes anywhere close to that. I did find a 2007 news account about WBO cruiserweight champion Enzo Maccarinelli, whose punches supposedly packed a wallop of around 3.85 tons. However, the researchers making this claim have yet to publish their findings in a scientific journal, and I’m not taking them seriously until they do.
Even without Drago in the ring, boxing is a punishing sport, especially where the head is involved. Damage comes from three things: (1) the impact itself, which may be manifested in, say, a broken jaw; (2) acceleration to the brain leading to abrupt contact with the skull, possibly resulting in concussion; and (3) the rotational force that twists the brain within the skull, increasing the severity of injury and the likelihood of a knockout.
One metric for gauging the risk and seriousness of a brain injury is the Wayne State tolerance curve, which looks at both the g-force imparted to the head and the span of time involved. Generally speaking you don’t want to take a shot of more than 50 g, although you can stand more if the impact is really brief — say, a couple thousandths of a second. If you’re on the receiving end of a Bruno-class impact, my guess is you won’t soon get up.
Punches to the head can cause detached retinas, brain hemorrhage, fractured bones, and permanent neurological disorders. As I’ve mentioned before, something like a fifth of boxers suffer from dementia pugilistica, the consequence of repeated blows to the skull; it’s characterized by slurred speech and halting gait. Worse can happen. According to one estimate, boxing killed at least 650 fighters from 1918 through 1997.
Mixed martial arts (MMA) fighters, interestingly, seem to be less at risk. Since MMA rules allow grappling (meaning less punching) and tapouts (giving up), actual knockouts occur only half as often as in boxing.
Besides maybe getting killed, cumulative brain damage is the scariest part of boxing, as most fighters now recognize. To quote Terry Marsh, the undefeated light welterweight champion, “I don’t need the British Medical Association to tell me getting hit on the head can’t do me any good.” Muhammad Ali would surely concur.
This article appears in Jul 21-27, 2010.
Great info! I’ve been looking for a little more info on this stuff all night. I watched an episode of Mythbusters last night that spoke of certain amounts of force that could possible kill someone. I thought they said 100 pounds of force could kill someone if the impact were in the right place. I may have heard it wrong. I was curious because I thought I recently read that professional boxers punch at a higher amount than that. So, I got online and could only find measurements in psi, which I knew wasn’t the same (but didn’t fully understand the difference until reading your article).
I appreciate the detail in explaining the differences in psi and force, as well as the results of your research on this matter. Great job! However, I’m more lost about last night’s episode of Mythbusters now. I’m curious what number and measurement they said, as I wasn’t fully focused on it, at the time. Oh well. No biggie, since I don’t plan on testing it. I noticed on some of your other articles a similar feel of research and detail going into the articles. I’ll definitely check out some more of them.
George St. Pierre hit 2800 on Sports Science
The units (lbs. force) that these are delivered in always messes with my head. Can someone with a physics background help me understand it? How do you measure ‘force’ (lbs.) when you’re dealing with an impact?
To me that seems like it should come out in units of energy or impulse/momentum. You have a moving mass, it hits something . . . how do you measure an equivalent force?
I’ve searched for exactly how Sports Science and others measure the ‘power’ of a punch (power in a generic sense, not time rate of change of energy) and they don’t get into that detail. I’d really like to find out, as force is a much easier quantity to deal with than energy or impulse.
In my limited understanding it seems like the only way you could equate that to a force is if you knew the precise mass of what was being moved by the impact and measured the acceleration. Easy enough in concept, but in the things that get hit on Sports Science, like the dummy, only a portion of the mass gets accelerated and in a way that’s not very predictable (a head on the end of a spring). A ballistic pendulum seems the most obvious way to measure a punch, but that yields energy (ft-lbs).
I hope I’ve explained this well enough that someone can enlighten me. You hear it all the time–things like “By the time the baseball hits it has x lbs. of force.” It would put my teeth less on edge if I understood how that’s a valid measurement of energy equivalence . . .
Thought experiment:
You have a mass hanging on a string. How do you change its weight without changing its mass?
You accelerate it. F=ma. The mass has a weight that is the product of its mass and the acceleration of gravity. So you could change that weight, measured in the tension of the string, by pulling on the string.
The key here is that when you get down to it a load sensor is actually measuring acceleration. Am I on the right track? Is that the secret to taking something dynamic like energy/impulse and converting it to more static units like force?
Okay, so you build a machine that uses a punch to pull the string. Measure the tension in the string (or rod), and you have a force measurement of a punch.
Oh, but the problem with all the machines I’ve come up with is that the free body diagram doesn’t take into account the energy to accelerate the mechanism, even if it’s balanced. D-oh!
Help me, Obi Wan Kephysics-major. You are my only hope.
Guys everyone one of you are misinformed and completely wrong. Force is subjective. The harder the surface the greater the force. Think of it as de-acceleration. No 2 studies can be compared as equipment varies so much in hardness. Its all a total crock. Professor David Sandler who wrote and stared in the Fight Science series admitted as such when i spent time with him on the set of Ultimate Fighter 2015.
Force plates are the most common tech around to provide these numbers but they only messure the impact.
The component they can’t measure is kinetic energy which results in the penetrative nature of the strike.
There is new technology that measures both by Strike Research. Everything else is completely meaningless and counter productive to our knowledge of combat sport.
I boxed professional,and hit 560 pounds per square inch at 125 mph as a light heavyweight. When I switched to taekwondo,I hit 380 psi at 110 mph,however,my spin heel kick topped over 1100 psi at 205 miles per hour.my martial arts stats were considered average for punches,and slightly above average for kicks.2150/psi is absurd.maybe from a freak of nature spin heel kick, but no way from a punch. The body simply cannot generate enough power from that short a short distance.
Frank Leany – the force talked about would be peak force. Whenever you apply a force to something there is a force time curve or force integral or impulse. This goes from initial contact to peak force and trails of to final contact (to put it simply) Force = mass x acceration (f=ma) but f-ma=0. Therefore anything you apply a force to also pushes back with an equivalent force, this push back is called inertial force. Inertia is a body’s resistance to change in (velocity) motion and is related to mass in that the larger the mass the greater the inertia. So if you punch a balloon you can’t apply much force to it because it moves (changes velocity) easily. A large punch bag has a lot of mass so it inertia is high and difficult to accelerate (acceleration = change in velocity)
So when you punch a bag or a person that has a lot of mass (weight) then as it has a lot of inertia then you are able to apply a lot of force ie you can get your body weight acting on it.
it doesn,t matter if are a boxer or martial artist. Your strenght depends on you and your body. i trained my body by doing a 100 push ups, a 100 sit ups, a 100 squats and a 10 km run every day for 3 years and now i am able to punch by the force of about 1,150 pounds
Kevin Franklin has no clue what he’s talking about. Learn some physics. “Force is subjective”??? what a funny joke I would laugh if it weren’t for the fact that he was saying it seriously. Yes, force does depend on the hardness, and can be measured, making it objective. No one says “oh it felt like 3 newtons of force so I’ma say it was 3 newtons” lmfao.
It IS much more accurate to measure brain damage in G’s (acceleration) rather than newtons. Because peoples’ heads come in all sizes! The G’s measures how fast the skull actually accelerated and it’s closer to the thing you REALLY want: The force that the brain hit the skull, not the force that the skull was hit.
“Penetrative nature” is absolute BS unless you’re actually measuring organ damage or something. Brain damage doesn’t come from people “penetrating” into the skull. It comes from accelerating the skull.
No boxer ever died from taking one punch, or even 100 punches. This includes Muhammad Ali, who didn’t get damaged by any “one” punch. They get damaged by the 100th punch or the 1000th punch not just any one particular punch. It is always the 10,000th, even though it can be filmed, seen by many individuals, etc. A former junior-middleweight champion, Eddie Pace took many beatings in his career; he was a straight ahead type fighter like Dempsey, Marciano, etc. and took a lot of beatings, especially by Freddie Little. He was sparring in the Main Street Gym, in L.A. whwn he was sparring with another boxer who hit him in a sparring session where he was knocked out. Unfortunately the punch was the one that killed him. It wasn’t that “one” punch, probably more like the 10,000th.
I wouldn’t take the study to show that the technique of the punches in boxing are superior in power to those of the martial arts other than boxing. The tests were of Elite boxers and 12 seemingly Random Karate black belts. In most martial arts being a black belt doesn’t even mean that you are good at the art. It just means that you’ve been doing it for a while and are at least semi competent. If you were to take martial artists with the same level of fitness as elite boxers, who were highly proficient in their techniques then punching power would probably end up being pretty close to the same.
Why boxer punching bag felt sore on his fist but when he punch a floating tissue paper with same amount forces he didn’t feel sore.
Where are the sources for the studies, I wanna read them