The Physics behind Martial Arts

Done by Aloysius Zai4A104

Contents

1. Introduction2. Punches3. Kicks4. Takedowns5. Throws6. Break Falls7. Body Parts8. Conclusion

Introduction

Just like any other sport, physics can be applied to martial arts and we can use this knowledge to our advantage by gaining the upper hand in combats and competitions by understanding the various concepts and principles behind martial arts.

Punches

In this presentation, we will be studying three punches:• A straight Punch • A Jab• A Hook

Straight Punch and Jab

By applying physics, we know that the most effective punch is the straight punch because speed is defined as distance over time and with a shorter distance to travel, the time taken for the fist to reach the opponent will be the shortest, compared to other types of punches.

HookA hook is a punch that comes from the side of the opponent, unlike the straight punch and the jab which comes from the centerline.In this punch, the fist of the person executing the punch would have to travel a longer distance before reaching the opponent so it would also take a longer time to reach the opponent. However, by using the equation Moment= f * d, we know that with a larger distance, there will be a larger turning effect of the force exerted by the punch. Therefore, it is more effective in bringing an opponent to the ground because a hook will turn the opponent’s body more and is more likely to take him off balance and fall to the ground.

Kicks

• In this presentation, the following kicks would be studied:– Front push kick– Back Thrust – Side Kick

Front push kick

By executing a front push kick, you are exerting all your body weight onto your opponent, concentrated on the area where your sole strikes the opponent and we know that F=Ma and P=F/A so a front push kick will exert a maximum pressure and Force onto the opponent, which may result in the breaking of bones or internal injury.

Back Thrust

• A back thrust is similar to the front push kick, but it is different in the sense that turning your body distracts your opponent and with the 180° rotation of the hip, there will be more kinetic energy present in the kick, and the kick will be more powerful, given that P=E/t

Side Kick

Side Kick

• A side kick in martial arts is usually executed after taking a step back with the non-kicking leg.

• This kind of kick would shorten the distance between you and your opponent and because the kick is coming from your side, your leg would reach the opponent before complete extension, giving the leg more contact time with the target area of the opponent and inflicting the most amount of pain on him, after complete extension.

Roundhouse Kick

• The very reason why the roundhouse kick is more effective than a backhand is because of a physics concept as mentioned earlier on- “moment”.

• Other than distance, momentum is also dependent on the length of an object.

• This idea can be summarized into the equation below:• Moment = Position of the object relative to the

fulcrum (Length) x Force• Therefore, because the leg is always longer than the

hand, a kick will always result in more impulse than a punch.

Break Falls

• Break Falls are absolutely necessary when being taken down or thrown in street fights and sparring sessions. Furthermore, it is also useful to learn break falls if you are the careless kind that will lose your balance by simply walking.

• Basically, the idea of breaking falls are to prevent injury to the whole body when falling down which will include sprains, fractures and even dislocations.

• When breaking falls, martial artists usually slap the front of their palm fully onto the ground with the arm being slightly bent (not locked out completely).

• As most judo masters would put it, this is to “absorb” the pain inflicted by the opponent but technically, slapping the palm onto the ground would spread the downward force exerted by the opponent’s throw to an area as large as possible, so as to minimize the pressure (and pain) felt by the martial artists.

• Break falls are also important, because it is always wiser to risk injuring a hand than to risk losing consciousness in the middle of a fight, which will prove to be extremely disadvantageous for the martial artist.

Throws

• Hip Throw• O-Soto-Gari

Throws

• Many throws in martial arts are revolving around the issue of center of gravity

• According to NASA, the center of gravity can be defined as the distribution of weight around a balance point

• A person's COG is located inside his body somewhere between his naval and the sacroiliac joint (where the spine meets the hip bones).

• Your opponent is stable as long as his center of gravity remains over the area supported by his feet.

• Therefore he is stable until you force him into moving his center of gravity, or into losing part of his support area.

Hip Throw

• The key to an effective hip throw is to make use of your hip to lift him off the ground and use your knees and arms to pull him forwards (and downwards), to make him lose his original center of gravity.

• Once his body is off the ground is his center of gravity is shifted forward, over your back, gravity will pull him down onto the ground in front of you.

• This is a vector diagram of the hip throw

Acting force

Resultant Force

O-soto-gari

• A.k.a The Major Outer Reaping Throw• By placing your whole arm around your

opponent when doing this throw, you are increasing the “target area” so when exerting force on your opponent, more pressure will be exerted to take him off balance (off COG).

• Sweeping your leg backwards will also take your opponent’s legs off the ground.

• With a combination of a forward and downward force, the opponent will be naturally brought to the ground

Note that the leg also acts as a pivot point to bring the opponent down

Body Parts

Other than fists and legs, these are some body parts also involved when sparring in martial arts

The ElbowThe Elbow is a CQC (close quarter combat) strike that will hit the opponent with a lot more force than a normal punch because Pressure = Force / Area and with a larger surface area (by striking with the elbow), more pressure will be exerted on the opponent, and if done properly, enough pressure can be exerted to send the opponents nose bone back into his brain, resulting in death.

The Hip

The hip is the most important body part for martial artists because it is the “power source” all attacks and defenses.

正所谓：“练拳不活腰，究终艺不高”

Using F=ma, we know that increasing the mass involved will increasing the force exerted. This is done by utilising our hip in the strike because involving more of your body will increase the mass and thus increase the force as well.

Conclusion

By applying physics, we know that to achieve maximum power for a strike, we need to strike fast and increase the displacement of the opponent’s body through deep penetration by using techniques such as side kicks and karate straight punches. Also, we should always utilize our hips be it executing throws, punches, kicks or blocks and that is why, it is always important for martial artists to train their hips and obilques to be strong and yet flexible.Lastly, martial artists should always relax and minimize muscle tension to increase acceleration and power.

Acknowledgements

• http://www.fightingarts.com/reading/article.php?id=281

• bushido-usa.com• http://wcats.com/WCLessons/Lectures/

LectureIII.php#1• Discovery Channel: The Human Weapon• Ron Young – 1st Gup Hapkido, Apex KiDoKwan– International Korean Martial Arts Federation