The opposing feelings of tension and relaxation can also be explained as 'contraction and expansion', 'open and closed' or 'full and empty'. Regardless of how we choose to explain this theory, we can support it with a variety of examples. Imagine a cat's stance before it gets ready to pounce. Contraction to expansion becomes the energy that the cat uses to lunge forward. Think of a time that you shot a rubber band. Expansion to contraction becomes the energy that propells the band through the air. This same relationship is evident in our Tang Soo Do techniques when we focus on how our hur-ri (hip) and dan-jun (center) are used.
Study the movement you were taught to perform a low block. You collapse your arms about your body (frame) and turn your hip in. As you move forward your arms separate and your hip moves out. This is an example of contraction to expansion. Think now of your movement during a center punch. One arm extends as you aim in preparation, chambering the other arm to the side, all while pulling the hip back. As you move forward your arms exchange position as your hip snaps forward. This is an example of expansion to contraction. What is your breathing like during these motions. The dan-jun (center of your abdomen) changes from full to empty, epecially as you ki-hap. Note that this change from full to empty aids in contracting the muscles of your body on impact or completion of the technique.
The important thing to remember is that being conscientious of Shin Chook helps us create power. The more proficient we are at defining relaxation and tension in our movements, the more effective we become in our execution of those techniques. If you try to move with tight muscles to be more powerful it actually works against you. It was once explained to me like this: when it rains, a drop of water falling through the air represents relaxation and the moment it impacts a surface represents tension. When thinking of it this way you can imagine that there is much more relaxation then tension to move gracefully through space. This is not altogether simple to implement, but don't be discouraged; the more mindful you are about your practice of tension and relaxation, the quicker you will be able to train your body to demonstrate the concepts accordingly.
Now that you are familiar with the physical (internal and external) applications of shin chook you should challenge yourself to discover ways that you can (or already do) apply the principle to the spirit of your training and life outside of the dojang.
The late Kwang Jang Nim Hwang Kee stated that the focus of our training is not the physical technique, but rather mental development, and that the Eight Key Concepts develop the total person. Integration of these concepts into personal life allows the individual to become more than an athlete. The benefits of utilizing these concepts and the ultimate purpose of training in Tang Soo Do is a rejuvenation and expansion of our lives.
“If a diamond is not polished it will be unable to show the great luster of the diamond itself. Even though we say the martial arts are good, we cannot show the great value of the art if we do not practice it with effort.” - Kwang Jang Nim Hwang Kee