Do not forget to correctly apply: strength and weakness of power, stretching and contraction of the body, and slowness and speed of techniques

Do not forget to correctly apply: strength and weakness of power, stretching and contraction of the body, and slowness and speed of techniques. Yes, repeating the words of a great master. What is meant here? How can strength and weakness be used in the application of karate. Or stretching and contraction? Even more so how can slowness and speed be useful in karate. What we have here is advise from an old master on how to improve your training in Shotokan Karate. Stretching and contracting of the muscles are necessary to fully perform a technique. Especially in kata training this aspect is important to look for. In Shotokan Karate one of the principles to look for in proper application of techniques is dynamic expansion (stretching) and contraction. In the practice of Shotokan Karate one should fully contract one set of muscles while stretching the opposing set. In any activity there is a set of muscles that are pulling the limbs into the movement and there is also an opposing set which if not properly relaxed will resist that motion. Another problem indeed. A karate-ka must work to relax the opposing set of muscles so that he/she can get maximum speed from the contracting set. This is an entirely different issue from what is stated in this quote but it is also an equally important concept that can not be over looked in training. The concept of expansion and contraction is a practice that enables the practitioner to get the last ounce of energy or power out of a given karate movement. To get this concept down, you must feel you muscles on the retracting or contracting side tightening. You must get in tune with your body and pay attention to what’s happening during the motion. i.e. During the performance of a shuto block or knife hand block, at the beginning of the technique or the chamber you should feel your chest muscles tighten and your back muscles should be stretched and at the completion of the block the converse should be true, the back muscles should be tight and the chest muscles should be stretched.
The reference in this quote to the use of slowness and speed of techniques also applies to both training of basic techniques and or kata training. In katas there are fast and slow moves. Most often these moves are meant to train your muscles. You are learning how to isolate the specific muscles needed for an activity. These tension or slow moves are also an indication that the old masters new about isometric exercise years before any personal trainer put a new name on it. So included in karate training is dynamic contraction and expansion exercises and at the same time a method to perfect a technique and also learn how to get maximum power from that technique.
The use of slowness and speed in your karate training is also a must if you want to perfect your moves. You must crawl before you can walk and walk before you run. A karate-ka must do a move, first slow the fast then slow then fast again. Get it right slow, then try it fast. That’s the only way to figure out a move correctly otherwise you will be very sloppy in your execution.
Keep analyzing the technique and then get your sensei to correct you. Above all when your sensei corrects you, practice it immediately and often. Practice it when he corrects you, not only in class but in your mind. Make it a point to never do it wrong again. Think about that correction and take it home and practice it as soon as you get home, then some more a little later and as soon as you get up. The more often you practice a fix, the more likely it is that you will become a very good martial artist.
There is a reason that teachers send home homework. Learning doesn’t end at the end of school. If it does then then you will not be great.
The difference between good and great is about 5 or 6 inches. Huh? Yeah, that’s the distance between your ears!!!
Sensei Culver Rokudan (6th Dan) Shotokan