Tuesday, May 1, 2012

Air Punches

What is an 'air punch'? The Urban Dictionary (apologies for the less then credible source) defines an air punch as: the act of throwing a punch in the air intended for someone or something, but without the physical contact.

Karate, kung fu, wing chun, taekwondo, etc., etc. all have their students standing in lines practicing their punches via air punches.

A recent blog on Japanese Jiu Jitsu: A Journey (http://japanesejiujitsu.blogspot.com.au/) raised the issue of keeping what is useful and discarding what is not, and the issue of how we decide between the two. The martial arts were developed by trail-and-error. Supposedly, those who discard the traditional techniques are doing so based on trial-and-error, although sometimes you have to question their 'trial'. That blog provided further support for my work. One way to evaluate methods we are unfamiliar with is by understanding the science behind the methods. The science is common to all methods; it is the essence of the methods and what makes them work, or not. What does science have to tell us about air punching; one of the most common ways to teach striking and kicking techniques in the martial arts.

A force is something that causes something to start, stop, speed up, slow down, or change direction. From a stationary position, a force is applied to an arm to start its journey and speed it up when punching. When the arm is extended and the punch is terminated, a force must have been applied to the arm to cause that arm to decelerate and stop. When we are talking about air punches we are talking about internal forces as no contact is made with another body or object which applies a force to that arm/fist. Internal forces start the punch and internal forces stop the punch.

All moving things possess kinetic energy. Energy can be neither created nor destroyed - it has to go somewhere. A moving air punch possesses kinetic energy. When a punch or kick stops moving it no longer possesses kinetic energy. Where did the kinetic energy go? It was absorbed by the puncher's body.

So, what are we training when we train air punches? We are training to apply a force to our arm to accelerate it in a particular direction and then to apply another force to decelerate and stop the arm, thereby doing 'work' on the arm and absorbing the kinetic energy in our own bodies.

Injury is defined by injury science as the exposure to energy in excess of the tissue's tolerance levels. Kinetic energy is transferred from one body or object to another via mechanical work. Mechanical work refers to force. A force is applied to another body or object which transfers the kinetic energy of the punch to the impacted body or object with an injury or damage resulting if the transferred kinetic energy is in excess of the impacted body or object's tolerance levels. The force applied to an impacted body is a different force to that applied to stop a punch without impacting another body.

A force is simply defined as a push or a pull. Pushing and pulling involves different muscles, as explained in Arthur Chapman's Biomechanical Analysis of Fundamental Human Movements. A force applied to stop an air punch has to be a pulling force, whereas a force applied to another body or object has to be a pushing force. By definition, the different actions have to involve different muscles.

A punch is designed to apply a force to another body or object, and to transfer the kinetic energy of the punch to the target. An air punch does not train the application of a force to another body or object. Rather, it trains the application of an internal force to decelerate and stop a punch, and thereby the absorption of the kinetic energy of the punch in the puncher's own body.

In addition, Newton's third law of motion states that for every action there is an equal and opposite reaction. Newton was referring to forces when he referred to actions and reactions. When we punch a body or object, the body or object 'punches' us back. The reaction force has to be absorbed in our own body otherwise it will cause a change in our motion or shape (the latter meaning deformation, or injury or damage). Air punching provides no experience of the reaction force exerted on us when punching.

The potentially deleterious effect of training air punching was brought home to me when I explored Bruce Lee's three-inch punch with two very experienced jujutsuka/aikidoka. One, who had trained for over 20 years, was literally rocked backwards when punching a thick text book held on his partner's chest. He had not trained, and had no appreciation of, the reaction force that accompanies a punch when impacting with another body or object.

An understanding of the science behind punching tells us that air punching is not punching.

I could leave the issue with the rather dramatic statement above. That would be the common approach. I would not abandon air punching simply based on the above argument, even as compelling as it is. Rather, I would look to air punching and ask, what is it actually training? After all, based on the traditional trial-and-error method, it appears to have some benefits. The trick is in understanding precisely what those benefits are. What the above analysis does demonstrate however, is that we have to train striking and kicking techniques by actually striking and kicking something. Otherwise, we are not training striking and kicking techniques.


  1. The tricksy, but not entirely off base answer is that air punching trains punching the air. Not every strike connects and it is useful to be able to recover from that. However, I don't think that explains all of it. One explain, which I would call the traditional one, is that it helps build the "form" of the technique by allowing you to follow the movement through without resistance. This sound somewhat convincing, particularly if supplemented with other forms of training, but I haven't seen much real evidence either way. Lastly, I would point out that airpunching is impressive looking and doesn't require much equipment, all things being equal these are plusses, but they also provide a way for a method to become popular to an extent not justified by its effectiveness.

  2. To my eye, the benefit of air punching is mostly a benefit to the school and the instructor. It allows him to impart the very most basics of striking to any number of students without having to supply each of them with a punching bag or partner.

    To the student it provides another method of training that does not involve impact - a very good thing if you happen to have an injury or bruising but don't wish to stop training.

    I am sure I'm missing a few others, but suffice it to say that after the most basic concepts of striking have been imparted, it is incumbent upon the teacher AND the student to incorporate striking of other objects or people in order to familiarize with how kinetic energy is transferred and how not to become injured from transferring that energy.

  3. Besides the obvious reasons of learning structure and dynamic of technique and that of polishing technique. I feel the stop you mentioned is key to the airpunching thing. It seems to teach kime and correct tension to absorb reaction force quite well. But it raises questions. To validate the practise such questions are important to be answered. Does the force to stop (kime)the movement in the air not transfer to the object when connecting? Does it really have purpose in the part were you learn transferring force? Maybe. Though I have to agree that training only airpunches without contact, would give a distorted picture of punching in general. Every kihon technique needs application practise. Or else you better not train it at all. Airpunching is just a small part of a bigger picture.

  4. I've done thousands and thousands of air punches without too much thought. Now I'm thinking about it...

    Good post and thanks for the mention.

  5. Thanks for the comments. Firstly, don't get me wrong, I'm not arguing against air punching as a form of training. What I am suggesting is that it needs to be supplemented with resistance punching in order to train different aspects of punching that are not present with air punching. The first of course is the issue of preparing the body to resist reaction forces when punching.

    Dojodelft - the transfer of KE causes injury when absorbed in amounts or rates that exceed tissue tolerance levels. KE is transferred via force (no matter what force-related concept is referred to). A punch possesses KE beause it is moving. With air punching, and internal force caused that movement, and an internal force stopped that movement. The KE was absorbed into the punchers body. When hitting another body or object, you want to maximise the KE transfer to that body or object. Any that is absorbed in your own body by applying forces to stop the punch is not available to be transferred to the target. I would argue that you want the target to stop the punch and not your own actions in order to maximise KE transfer. I'm not ignoring the unbalancing implications, but when impacting something you want that something to do the stopping so that force is applied and KE is transferred.

    Of course these theories have never been tested. As one author writes when reviewing the martial arts literature related to biomechanics, the biomechanics of martial arts is in its infancy.

  6. Hi John, moving from air punching to punching a pad is a big transition for many beginners. It takes a while to build up confidence and get used to the feel of it. Even grown men punch very lightly when they first start punching a pad! Air punching definitely helps to improve form but pad punching is needed to improve function. Of course karate is not just about punching - we use every available surface of the hand - knife hand, ridge hand, back fist, bottom fist, ippon ken, palm heel etc. We also teach striking from hard to soft or soft to hard to avoid injury and also to target vital points. The straight punch is probably the least useful of the strikes in reality. It's more about striking intelligently than powerfully...

  7. Hi Sue. Thanks for the comment. Again, I hope you didn't take from my blog that I'm anti-air punching. The point of my blog was to point out that it involves different dynamics than impacting a target.

    I thought of another way of thinking about it. Anytime something starts, stops, speeds up, slows down, or changes direction, a force was applied and which caused that change in motion. With air punching, the punch stops so an internal force was applied to stop that punch. When punching a target, a force is applied by the target to stop the punch. That is what needs to be learnt; to let the target apply a force and stop the punch so the maximum amount of kinetic energy can be transferred to the target. Any internal forces used to stop the punch even when impacting a target must be bleeding off some of the kinetic energy.


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