Osu!
Tsuki (punch) generally means choku-zuki. Chudan-Tsuki is a "thrust" punch with seiken delivered at a target directly ahead. turn the forearm inward 180 degrees and extend the arm as if it were a spear thrust forward from the side. This action will impart a powerful shock to the target.
Tsuki directed at the face is called jodan-tsuki (upper straight punch), at the solar plexus area tsuki-chudan (middle straight punch), and at the lower abdomen gedan-tsuki (lower straight punch).
Ideally, chudan-tsuki should be powerful enough to incapacitate the opponent, but this effectiveness cannot be developed in a "day". Continuous daily practice over a relatively long period of time is necessary to forge chudan-tsuki into a strong weapon. But this practice must be properly done if it is to be effective. Therefore, the student must concentrate on the following points in training.
Route of tsuki:
Tsuki will be ineffective unless it travels to the target over the correct route. The "correct" route in case of the straight punch is a straight line from the starting positing of the fist to the target. This can be done if you brush the inside of your elbow against your side during the course of the punch, and turn your forearm 180 degrees inward before you hit the target. These actions help to insure that power potentiality in the Punch does not go astray. If this power is transmitted on an unwavering line to the target, it will produce maximum shock upon impact.
Tsuki Speed:
The formidable shocking power of karate techniques result from the momentum generated by the movement of various parts of the body, climaxed by a focus of these components at the instant of contact with target. Speed is a major requirement in this operation. In fact, speed is of first importance from start to finish in the training in fundamental techniques. The faster the muscles are tensed, the more speed and, ultimately, the more power will be in th Punch or kick.
To increase the speed of a punch, make use of the reaction of the opposite arm, hikite. The faster you retract the hikite arm, the more speed and power will be evident in your punch. When the arm is stretched during the course of the punch, one group of arm muscles stretches, while another contracts. Proper balance must prevail between these two muscle groups for a speedy and effective punch. If, for example, the muscles which must stretch are tensed, the arm movement will lack smoothness and the punch will be ineffective.
Beginners often use unnecessary muscles with the necessary ones. They must learn which muscles are essential for the performance of a particular movement and use only those. Effective techniques depend on the proper selection and use of the body's muscles.
Concentration of Power:
Deliver a thrust punch by stretching the arm smoothly and rapidly toward the target. Release all unnecessary tension from the arm and hand at the start, but be sure to concentrate all the power of the body in the punching fist at the moment of impact. Make use of the reservoir of power stored in the hips as you begin your punch. This power flows through, and is increased by, the muscles of the chest, shoulder, upper arm, and forearm. This principle also holds true in case of strike or kick. Remember that an effective technique in karate is produced by a concentrated blast of power at the moment of impact.
Muscles at the front and side of the abdomen are strongly tensed, linking the chest and the hipbones firmly together. When the hips are properly set and th body is correctly supported by the thigh muscles, the standing position is firm and stable. This stable foundation enables the power of the hips to flow to the chest, shoulder, and the arm. Arm muscles used in raising the arm and those which straighten the arm are strongly tensed, as are the forearm muscles. Muscles around the armpit are flexed to prevent a rebounding or flying backward of the arm and shoulder when the fist hits the target.
Power can be concentrated only when the hips, chest, shoulders, arms, wrists, and fists are firmly linked, and all necessary muscles function fully. If, during a thrust punch, the shoulder is "raised" or moved forward in advance of the movement of the body, you will be able to tighten the muscles at the side of the chest fully. Even if the arm muscles are tensed, the reaction of the impact will cause your punch to rebound off target. Bet you did not know that.
Muscles Used in Tsuki
Biceps, triceps, deltoid, terres major, serratus anterior, latissimus dorsi, obliques abdomens pectorals major, Retus abdominis. Bet you did not know that. Remember these points:
XXXX wrong shoulder drop too low (tilted) shoulder raised (shrug) shoulder thrust too far out (over extended)
Axiom-Keep shoulders relaxed, natural and steady during the movement
keep the upper body perpendicular to the ground. Do not lean forward.
Form seiken correctly and firmly
Be sure the punch travels to the target along the most direct rout
When withdrawing hikite pull it back as if to hit the hip. Withdraw the hand with maximum speed
Keep the shoulders relaxed and in a natural position. There is a tendency for the shoulders to rise or for one shoulder to move ahead of the other
Last tense the abdominal muscles properly.
P.S Dynamic Karate M. Nakayama 1966