Monday, April 9, 2012

Three-inch Punch vs Reverse Punch

I'm currently writing an article I'm planning to submit to Journal of Asian Martial Arts (JAMA): 'Injury Science: The Science Behind Striking and Kicking Techniques.'

JAMA is a semi-academic journal which means it provides serious scholarly work instead of just the 'pulp' that most martial arts magazines provide.

The article I'm writing explains the science behind striking and kicking techniques, and commences with examples of explanations that have been provided within the martial arts literature that at the very best is simply science for the sake of science, and at worst actually misdirects readers.

My research involves reading articles buried in academic journals that normally never see the light of day, unfortunately. This is the norm for most real-world activities but more so in the martial arts which is a bastion of anti-intellectualism.

One article I came across yesterday is, 'A comparison of the reverse punch and power punches in oriental martial arts' by J.K. Gulledge and J. Dapena in Journal of Sports Sciences 2008 26(2): 189-196.

The power punch is the infamous three-inch punch popularised by Bruce Lee. We also have the even more infamous one-inch punch. The idea behind these punches is that they only travel three or one inches to the target/opponent and they are 'powerful'.

The aim of the study was to compare the power punch with the reverse punch in regard to potency and to effectiveness in throwing the opponent offbalance.

The study used twelve 'expert' martial artists with six representing Chinese kungfu, three Japanese karate, and three Korean taekwondo.

The results were:
Similar impulses were exerted on the target with both punches, but the maximum amount of force exerted with the reverse punch was almost twice that exerted with the power punch. Therefore, the reverse punch was by far the more potent of the two.
The power/one-inch/three-inch punch is dead. Long live the power/one-inch/three-inch punch. The amount of nonsense that is written and taught about these types of punches is amazing; well it would be if the martial arts was not characterised by ego and gullibility.

An understanding of the science behind striking techniques would immediately suggest the power punch is significantly less powerful than a reverse punch, in fact, any other punch. An understanding that has not been provided in the martial arts literature todate despite the many attempts at using science to understand striking techniques in the martial arts literature.
Disabling the opponent through a potent impact may not be the only goal of a martial arts punch; another possible goal is to throw the opponent off balance. The effectiveness of a punch towards the achievement of this second goal may be measured best through the total impulse exerted on the opponent, and in this regard the power punch performed well. Although the reverse punch exerted a larger maximum force than the power punch, the force decreased more slowly in the power punch, and therefore the impulses exerted on the target were not very different in the two types of punch. In fact, the cumulative impulse exerted on the target during the first 0.20 s of contact was somewhat larger in the power punch than in the reverse punch. This supports the concept of the power punch as a push rather than a punch, ....
Firstly, forces can cause a change in motion or a change in shape. A change in motion can offbalance an opponent. A change in shape can injure an opponent. Secondly, relating the academic study to practice, the power punch applies a force that is more like a push rather than a potentially injurious punch. It applies forces that are more likely to change the motion of an opponent than it is to deform their tissues causing an injury.

The suggestion that striking is used to offbalance an opponent is interesting. Another study buried in another academic journals that studied the biomechanics/physics of karate suggested that 'the primary purpose in striking an opponent is to maximise the deformation damage at the area of contact, and it is only rarely that moving the opponent’s body as a whole is desired.' I'm not suggesting strikes and kicks are not used to offbalance an opponent. The taekwondo pushing kick is specifically designed to do just that. But what form of offbalancing are we referring too? The aforementioned pushing kick, and the power punch referred to in the study, physically offbalance an opponent. However in many jujutsu/aikido systems, striking is often used and referred to as 'mental unbalancing.' They are used to stun or distract in order to facilitate the execution of a finishing technique. They apply forces that are designed to deform the opponent's tissues and not to change their motion, but not deform those tissues sufficiently to cause an injury.

Return to the top of this blog and look at Bruce Lee's demonstration of his one-inch/three-inch punch. Note the punch receiver's stance. It is a parallel stance, which means it is less stable to forces applied from the front or rear - the direction of the 'power punch.' Would the same dramatic effect have resulted if the receiver had stood in a staggered stance, as in a boxer's stance or zenkutsu-dachi, which is more stable to forces applied in those directions? Note Lee's leaning forward when executing the punch. The one-inch or three-inches only refers to the starting distance between the fist and the receiver. The distance actually travelled by the fist is further because he leaned in, putting more bodyweight behind the punch which results in a greater 'pushing' force being applied to the receiver. Lee's demonstrations were contrived and designed for dramatic effect.

Lee's demonstrations always involved pushing and not injuring the receiver of his punch. How anyone can suggest the power punch can cause injury given Lee's demonstrations is beyond me. Next we'll be talking about a 'death touch'; oh wait, we do talk about a death touch in the martial arts.
Given these characteristics, several conclusions can be drawn with regard to the use of the two punches in combat or sport. The power punch will be slightly more effective than the reverse punch when the goal is to throw the opponent offbalance.
That conclusion is a bit sweeping. A reverse punch can also offbalance an opponent rather than injury them, or simply deform their tissues without injuring. However, a power punch does not possess the kinetic energy to injury in the vast majority of cases.
In addition, it may provide the advantage of surprise, since it requires less time for its execution. It is also possible that the power punch might be the most effective for the delivery of a disabling blow when only limited amounts of space and time are available for the delivery of a punch. However, when sufficient space and time are available, it is clear that the reverse punch will be the most potent.
Now they are simply contradicting themselves when suggesting the power punch could ever be a disabling blow under any circumstances. It simply does not possess the kinetic energy to cause damage.

Note I referred to kinetic energy above. Why didn't I refer to momentum like so many others do when attempting to explain the science behind striking and kicking techniques? That is a question I cover in my article.

The study used a force plate to measure the force applied by the punches. So do some other studies regarding punches and kicks. What a brilliant training aid. A training aid that is currently not used in most, if any, martial art. Can you imagine being able to quantitatively measure the force applied by a student's punch or kick. No more 'feel', now we could quantitatively measure the progress (or not) in a student's punch or kick. I'm currently sourcing a force plate and will advise in the near future.

A force plate would also provide a definitive answer to questions raised concerning the efficacy of different striking and kicking techniques, and those of different martial arts. Wing chun tends to make some pretty extravegant claims concerning the power of their punching techniques, even though they travel relatively small distances similar to a power punch. Do they apply as much force as wing chun exponents claim? If so, how, given they do not travel any large distance that is required to build kinetic energy? Considering these questions leads you to understand the essense behind the efficacy of these techniques.


  1. Interesting timing of your article on the one inch punch as I have just finished watching a documentary about Bruce Lee, which featured several examples of the famed one-inch punch.

    Odd thing is that while the man himself has always impressed me on the physical, psychological, and philosophical levels, I have never been awed by the one/three inch punch and have always been confused by those who were.

    These strikes have always appeared to be more of a shove to my eyes. This is reinforced by the fact that when he did this to an untrained photographer, the man stood right back up (albeit, several feet back from his starting poitn) and appeared to be uninjured. This would not have occurred if it were a reverse punch from any half-decent fighter.

    Also, when you do find a force plate, please post it as I have always coveted owning one myself.


  2. John, did you ever finish the first article for JAMA on throwing and takedown techniques?

  3. Paul, yes I have finished the throwing v takedown techniques article. I'm currently waiting for a credentialed friend to edit it before I send it to Attilio Sacripanti (Chair of Biomechanics at University of Rome) to review. Then, I will submit it to JAMA.

  4. I'd love to see high-time-resolution graphs of the force transmitted by different strikes! Can't wait for that article.

    Minor disagreement near the end of this one, though:
    > Now they are simply contradicting themselves when suggesting the power punch could ever be a disabling blow under any circumstances.

    "Limited amounts of space and time available" suggests, to me, that the opponent is in a compromising position and your fist is already extended near an ideal target area. I'd rather stand up straight and take ten reverse punches to the stomach than lean backward, off balance, and take one "power" punch.


Your comments make my work all the more relevant as I use them to direct my research and theorising. Thank you.