For those of you hoping to hear about flying, spinning kicks as seen in the movies…Sorry. You’re not going to get that here. What I would like to discuss here mostly concerns the physical forces at work while rotating body parts around a central point. There are many examples of this type of motion in karate techniques. I will only be touching on some of the more obvious ones here.
Ice skaters & ballet dancers
Skaters and ballet dancers often spin during their routines. So they must be very conscious of how it is done. One way that their methods of spinning differ is the position of the eyes. In ballet, it is almost always taught that the eyes should remain fixed on a certain point while spinning, rotating the head very quickly around to look at the same point on each revolution. In skating, during very fast, long spins, a skater will often turn his/her head with the rest of the body and “blur” his/her vision, as not to focus on any one point. In Karate, there are very few times that we would ever spin more than 360 degrees and focus is usually only on one opponent at a time. So the method for ballet (turning the head sharply and focusing on one point) is recommended almost universally for karate techniques.
Although skaters and ballet dancers may think of their line of vision differently, their spins share many similarities, due to the laws of physics that apply to them (and karate spins as well). Centrifugal force (tending from center) is a term used to describe the force of rotation around a central/pivotal point. Here are a few points to consider relating to this force:
During a spin, the closer the mass is to the center/pivot point, the faster the rotation can occur (all else being equal). Think about the ice skater when she brings her arms in on a spin.
The closer the mass is to the pivot point, the more easily that mass can be controlled (all else being equal). You can test this on some amusement park rides.
An obvious example for spinning practice is ushirogeri (back kick). I’m not talking about a spinning back kick here. Let’s stick to the basic Shotokan back kick for this example. Applying the ideas presented above, the spinning should be done with the mass as close to the pivot point as possible for maximizing speed and control. If the upper part of the leg is lifted too far to the side of the body, there is some loss of speed and control as a result. If the foot does not rise toward the back of the leg quickly enough, this also can cause a loss of speed and control during the technique.
This idea can be extended to other techniques as well. The kicking leg in mawashigeri (round-house kick), for example, also travels around a horizontally spinning center (in the large, basic version, anyway). Thus we should think about getting the foot close to the back of the kicking leg and connecting the whole unit of the kicking leg (during the chamber position next to the upper body) as close to the torso as possible for maximum speed and control. One obvious difference between the basic mawashigeri and basic ushirogeri is the path of the kicking foot. Because the mawashigeri involves approaching the target from the side, the knee rises more to the outside of the body than in ushirogeri. Another point to consider in both (as well as other) kicks, is that keeping the torso vertical throughout the movement also helps to keep mass near the axis of rotation; thus also adding to efficiency of motion and control.
Another point to keep in mind while spinning is that the shortest distance between two points is a straight line. While spinning the leg around in the back kick, the path the foot travels from the floor to the target should essentially be a straight line. Some people seem to have a hard time believing this, but this straight course can be accomplished while using a circular motion of the body. In geometrical terms, the path of the leg can be thought of as a tangent off the circular motion of the body’s center. (This may be more easily understood after I add more graphics to these pages in the future.) Of course the back kick can involve approaching the target from the side (spinning back kick). But although this can be a powerful kick (if done correctly), it takes more time to deliver (physics’ rules, not just mine).
Copyright © 2022, Jon Keeling (originally published June 1998)