Injury Science (Chapter 11)

As you may recall, my current book emerged out of my originally conceived how-to book on the tactics and techniques of Jan de Jong jujutsu. The original idea was to put a little science behind each subject in order to facilitate the understanding and study of the tactics and techniques of Jan de Jong jujutsu. The 'little science' that I uncovered, and developed, came to overshadow the how-to instruction and voila, my new book was born.

I'm not the first to attempt this approach. In fact, there are books and articles which are being published devoted to the use of science to facilitate the understanding and study of the tactics and techniques of the martial arts. With regards to percussion techniques (a generic term coined by Donn Draeger to refer to all techniques where the extremities are used as blunt force instruments), the published information definitely does not facilitate my understanding and study of these techniques.

These techniques have been described in terms of physics concepts: momentum (mass (M) x velocity (V)), kinetic energy (1/2MVV), force (M x acceleration), power (force x V). There was also impulse which is the average net force acting over some interval of time which will cause a change in momentum of an object. And the conservation of momentum principle and its application to collisions - elastic and inelastic collisions. All of which did not facilitate my understanding and study of any percussion technique.

In Fighting Science: The Laws of Physics for Martial Artists, Martina Sprage describes three types of impacts: (1) stinging impact which is 'not really related to the physics of power, although it does have a valid strategic purpose'; (2) shattering impact which has 'a lot of kinetic energy' that goes straight through the target' and is the 'most damaging'; and (3) pushing impact which has 'a lot of momentum' and is useful when 'unbalancing an opponent and as a power move.' She then suggests that when focusing on shattering impact or pushing impact you should focus on kinetic energy and momentum respectively. Given both kinetic energy and momentum contain the same variables, how do you focus on one to the exclusion of the other? Increase M, increase both kinetic energy and momentum. Increase V, increase both kinetic energy and momentum, albeit at different rates. How do you focus on shattering impact or pushing impact exclusively?

In Scientific Karatedo, Masayuki Kukan Hisataka refers to physics concepts. As with Sprague, he advises to focus on V due to its logarithmic effect on kinetic energy. Fair enough. If we focus on, and increase, the velocity of our percussion techniques we increase the kinetic energy of the moving extremity - so what? He then goes on to focus the majority of his discussion on momentum. How is that related to kinetic energy? And, as with the kinetic energy question, so what?

In an article entitled 'The Physics of Karate Strikes', Jon Chananie explained the 'collision mechanics of a hand strike to a solid target like a board.' In answering the question 'what makes a "hard strike"?' Chananie discusses the transfer of momentum and kinetic energy. How do you reconcile the two concepts given they have different properties? And when you transfer momentum and/or kinetic energy, what does it do?

There are numerous examples of the use of science which do not facilitate the understanding and study of percussion techniques, however, I'll cut to the chase. I can see the sceptics nodding their head and telling me 'I told you so'; science has little to contribute to the facilitation of the understanding and study of the tactics and techniques of the martial arts. Given my dogged (OK, obsessive) nature, I wasn't about to concede defeat. Nor was I prepared to reproduce the same 'academic' information which does little to facilitate the understanding and study of percussion techniques.

I never formally studied physics. I couldn't reconcile momentum with kinetic energy and its effects on an opponent. In fact, I couldn't reconcile these concepts with impact on an opponent full stop! What these concepts told me was the extremity in motion had a particular property - so what? So I looked at the issue from the other side and asked the question, 'what is an injury and what causes an injury?'.

My research on the Internet and at the Medical Library of the University of Western Australia was initially focused on trauma. Not finding the answers to my questions there, my research shifted to forensic pathology. Interesting, and disturbing in how we humans can inflict oh so many life-taking blunt force trauma injuries on fellow human beings which were graphically illustrated in the text books (this would not be the first time I studied forensic pathology for information on the techniques used in the martial arts). But still I didn't have the answer. I couldn't reconcile the physics concepts of a moving extremity with the injury caused (I'm an accountant and an analyst so I'm big on reconciliations).

Purely by chance, or not given my research endeavours, I stumbled across a relatively new science devoted to injuries called 'injury science.' In 1961, James Gibson promoted the idea that injuries to living organisms can only occur through the exchange of energy. A few years later William Haddon expanded the definition of injury to include the absence of critical elements such as oxygen and heat. Today the definition of injury reflects Gibson's and Haddon's work as the World Health Organisation definition of injury illustrates:

Injuries are caused by acute exposure to physical agents such as mechanical energy, heat, electricity, chemicals, and ionizing radiation interacting with the body in amounts or at rates that exceed the threshold of human tolerance. In some cases (for example, drowning and frostbite), injuries result from the sudden lack of essential agents such as oxygen or heat.

Mechanical energy is kinetic energy. All the other physics concepts used by all the other authors to understand and explain percussion techniques are now of, at the most, academic interest. The concept of kinetic energy is the basic, and possibly the only, concept of interest in facilitating the understanding and study of percussion techniques. And all we are looking at is M and V. Mass and velocity ... and the transfer of this kinetic energy from one body to another.

There is a lot more. My work obviously explores this issue at greater depth. There are a number of elements involved in M and V and the transfer of kinetic energy. I've developed a model based on the concept of kinetic energy which can be used to understand and explain all the different methods of executing percussion techniques and how they are designed to cause injury, or not. A simple model which expands on 1/2MVV. It can be used to understand the different approaches adopted by the different martial arts. It can be used to truly appreciate the combat effectiveness of Jack Dempsey's 'falling step' in his brilliant Championship Fighting: Explosive Punching and Aggressive Defence. Going off point for the moment, Dempsey's book published in 1950 is a revelation. Even though it is to do with boxing you'd swear you were reading a book on Asian martial arts at times. Back on point, this model can be used to answer the naysayers of the wing chun punching methods and their short movements. And more ...

I'm attempting to juggle the competing demands of providing information to keep my 'followers' interested in my blogs, but more importantly my work, and not revealing all my work prior to the publishing of my book. Paradoxically, I don't think that will be too much of a problem given the quantum of material/knowledge I've accumulated and developed which cannot be given justice to in a short(ish) blog. Anyone who has received any of my emails discussing my work and ideas will attest to that.

So, that forms the basis of my now planned chapter eleven. What do you think?

John Coles

PS: I've received some very encouraging emails expressing interest in my work. Thank you. Given the amount of time I've devoted to researching and writing this book, with no income coming in for a number of years, I do go through some 'what the hell am I doing' moments. When I receive emails of support and encouragement, or expressions of interest, I find an answer to my doubts. Thank you.