Aside from “point sparring” martial artists are generally taught to kick (generally a hand held target or some type of heavy bag) with accuracy and great power. One advantage to kicking is applicable distance. Since the human’s legs are typically longer than the arms, a kick can generally be delivered from outside the opponent’s hand striking range. Given timing and accuracy a good kicker should be able to land an effective kick well before the opponent can evade it or move in for a hand strike or a grappling technique. Given the amount of power a good kick can generate this one weapon can devastate an attacker. All this is true in a controlled environment, especially inside a martial arts school, a gym or a sports arena and it can be equally true under favorable conditions on a street, sidewalk, parking lot or even a grassy field. However there are a number of considerations to ponder when contemplating the value of a powerful kick in a real world “street fight” confrontation.
The typical showy or flashy high (head shot) kicks typically seen in movies and even in sparring matches can be dangerous to both the kicker and the opponent. Obviously if a good, solid, powerful kick lands against your jaw or face there is a good chance you will be badly injured or knocked out. On the other hand a high kick leaves the kicker wide open in very vulnerable areas. If he misses or if the defender grabs the kicking leg the entire scenario reverses. Even Bruce Lee is said to have emphasized that in a real fight he would never throw a high kick but would kick toward the legs to stop the attacker. If you think about it taking an attacker’s knee or leg out of the fight essentially takes the whole person out of the fight.
Then there is the law of physics which stipulates that for every action there is an equal and opposite reaction. Applied to kicking, consider this example: When you kick, especially with a great deal of speed and/or power, all or most of that power is transferred as a reaction to your support leg. When your supporting foot has good traction and your supporting leg muscles are strong the reaction is transferred to the leg muscles and eventually, in a way, to the floor. Try starting out on a relatively small piece of cardboard or other dry, slick material, laid on a tile or other hard, smooth surface. When you deliver your kick you will undoubtedly slide the cardboard (and your whole body) in a direction opposite from that of the kick’s power. If your kick makes contact with a heavy object you will move back farther. At best the result of contact will be significantly less power than had you been able to remain in a fixed location.
How does this relate to self defense? Most violent unexpected attacks or confrontations happen in parking lots, parks, sidewalks or even in some cases bars and clubs. There can be any number of ‘foreign objects’ or materials on the “floor surface”, from sand to gravel, to garbage, to banana peels, paper, etc. Any of these elements will tend to make kicking much more of a challenge than in a controlled environment. A firm but uneven surface, loose sand or gravel, etc., can destroy the effect of the best kicks when the decision to kick is sudden due to an unexpected attack and the kicker does not have time to really get a feel for his surroundings or the surface conditions he will be kicking from.
Then comes the balance part of the equation. Most humans have two legs. Unlike a three legged stool or a four legged animal, two points of support leave us tentative at best. The only real reason we can even stand upright is the structure and ability of our muscles. As an experiment (with a willing partner) look at your partner’s stance as two legs of a three legged stool. Visualize where the third leg should be. Then push him toward where the third leg will be. (You will have two options, one to the front, one to the rear). His balance will be disrupted easily. Pushing in any other direction will be more difficult since the legs and muscles are automatically set to prevent balance disruption.
Now, go to a one legged stance. There is really no point where you are stable if anything pushes against you. Visualize throwing a good, strong kick and just as your kicking leg starts toward the target your opponent’s girlfriend or buddy grabs you from behind or bumps you. It doesn’t take a physics major to understand what will happen.
There are indeed some really good and effective low kicks that can work under most conditions but generally these are fairly close range kicking techniques. Virtually all of them go for the legs, quads, shins, ankles, etc., and some even aim for the area of the kidneys. Most can be delivered with minimal difficulty (if you practice, of course) even if you are being grabbed by an opponent. Generally these are not “takeout” or debilitating kicks, although some of them certainly can be. More often they are painful distractions which will buy you time to initiate a strike, joint lock or other technique of your choice. Remember that once an attacker is distracted, even for a second, you have disrupted his game plan and bought yourself time to execute yours.