Tension vs Relaxation
Relaxation and tension (muscular contraction) are both necessary parts of proper karate technique. Some people are naturally tense, and have an easy time tightening their muscles during a technique, but find it difficult to relax in between. Others tend to be more relaxed, and have an easy time flowing through motions which do not require any tension, but have difficulty tightening the muscles during techniques where it is important (usually at the moment of impact). The ability to make a movement tensed or relaxed, therefore, is often dependent on the particular individual.
You may have a difficult time relaxing OR tensing muscles; most people find one state easier than the other. No matter which you find easier, you must try to enable yourself to switch back and forth at will to maximize the efficiency and effectiveness of your karate techniques. It is easy enough for most to flex and relax muscles slowly, in a controlled environment. But to quickly relax, then tense, and then relax again in a sparring situation takes much practice. This control of the contrast between tension and relaxation is one of the most important physical components of proper ‘kime’ (focus*), and should be a subject of study for any serious karateka. Below are two basic examples of this contrast.
*The actual definition of “kime” is “decision,” as in “to have a decisive (=effective) technique.” The term refers to both the physical and non-physical aspects of focus, among other things. In this article, I am refering only to the physical side of this focus, particularly the idea of muscular tension timing.
Contrast between tension & relaxation of the upper body when executing a basic gyakuzuki (reverse punch):
Although the tension in the lower body (the legs and hips) remains at nearly the same level throughout this technique (especially so if in performed in a basic front stance), most of the muscles of the upper body change from a relaxed state to tense during the punching motion. Although many are tempted to put a lot of tension in their upper arm at the moment the punching arm begins to move from its starting position, there is little need for such tension at that point. In fact, it will slow you down if you put too much tension into the arm early in its execution. Tension slows the speed that the muscles move. Imagine what happens to water when the temperature suddenly drops. Ice is hard, but it does not move quickly. Try to keep your upper body flowing, like the liquid state of the water, at least up until the moment of impact. Put only enough tension in the muscles of the arms, chest and back to get the arms to move in their proper courses. At the final instant, tense all the muscles of the body that you can. This is the idea of flowing like water at the beginning of the punch, but ending as hard as ice; same substance, different form.
Contrast between upper body relaxation & lower body tension when executing a basic maegeri (front kick):
I will not get into the tension and relaxation of the kicking leg itself here. What I would like to point out is the difference between the tension that exists in the legs through most of the kicking motion, and the almost total relaxation of the upper body throughout the movement. There is really no need for any more tension in the upper body than is required to keep your guard up (or wherever you choose to put your arms when kicking). Unless you are punching, striking or blocking at the same time as you kick, you should notice a large contrast between the tension of your legs and the relaxation of your upper body.
In both of the above examples, it should be noted that the muscles to be tensed are those located between the points of contact. The feet contact with the floor and the hand with the target, for gyakuzuki. All the muscles in between can add to the effectiveness of the punch. (Note that it is not really necessary to tense the pulling arm, as this is not between the points of connection.) For the kick, there is only one foot on the floor. Between that foot and the one at the target, only the leg muscles exist. Other (upper body) muscles do not contribute.
For practicing proper contrast between relaxation and tension, I suggest the following exercise with chokuzuki (basic standing “straight” punch)-
a) Stand in shizentai (natural standing position), with left arm extended in punching position and right arm drawn back as in normal practice.
Put only as much tension into the arms as is required to keep them from falling to your sides.
b) Open both hands to further relax your arms & wrists.
c) Slowly pull your left hand back as your right arm advances.
d) Only after your arms are in their final positions (like normal chokuzuki), rotate the wrists.
e) Close the hands, tensing all the muscles situated between the floor and the target. After about one second of total tension, relax.
f) Repeat until comfortable, gradually reducing the time of tension.
2. Try above with hands in fists the whole time, but keeping the same (lack of) tension in the hands & wrists.
3. Gradually increase speed.
4. Do again in zenkutsudachi.
5. Advanced karateka may want to try the same thing, but with the arms in jiyuu kamae (free sparring position), trying to create the same contrast between tension & relaxation in a shorter distance & time.
Very advanced karateka are capable of accelerating their hands (or feet) towards a target at great speeds, aided by proper relaxation. Then timing the tensing of many different muscle groups at the final instant to create explosive power. I’ve seen a man in his late 80’s break a pile of roofing tiles in Japan without moving his hand more than about an inch from the top tile. And remember Bruce Lee’s ‘one-inch punch?’ These are extreme examples of successful contrast between relaxation & tension utilized within a very short period of time.
For more on this subject, please see http://www.baylor.edu/~BUKarate/articles/relaxation.html
Copyright © 2022 Jon Keeling (originally published February 1998)