Three types of body motion generate power
- Linear. The body and center of mass move in straight line toward the target behind the technique.
- Circular. The body rotates or twists around a vertical axis that extends through the center of mass so part of the body's mass is rotated toward the target behind the technique.
- Pendulum. The center of mass rises and falls toward the target behind the technique.
Linear motion (thrusting)
Linear motion refers to thrusting the hips, body mass, and technique straight toward the target. The pivot leg, which provides propelling force behind the movement, pushes the body forward by the reaction that occurs when it is straightened and thrust backward and down ward against the ground. The faster and harder the leg is thrust against the ground, the more powerful the movement toward the target. The faster the mass of the body is moving when the technique impacts, the more power that will be generated by the technique. For this to happen there must be a tight connection between the lower and upper body. For this connection to occur the muscles of the abdomen, lower back, and sides must be contracted.
Things to avoid:
- If the thrust of the rear leg is weak, often the movement is made by tilting the head and shoulders forward. This impairs stability and results in an ineffective technique. Instead, keep the hips and upper body in vertical.
- If the heel or the rear foot is raised, it is difficult to use it properly for thrusting against the floor. However, allowing the rear foot to rise on the ball of the foot does allow extra reach on reverse punches.
- If the movement of the hands and the feet is not coordinated with the movement of the rest of the body, it is impossible to achieve a focused technique. All parts of the body must arrive at the point of impact at the same time.
Circular motion (hip rotation)
Hip rotation helps achieve maximum power in any technique, whether it be using punches, kicks, or blocks. It is used in combination with other body movements to complete a technique. As stated above in the equation F = ma, force is increased by increasing mass or acceleration. The fist has a small mass, but, by linking it to the mass of the entire body, the striking force of the fist increases. Techniques that only use arm or leg muscles for power do not draw on the power of the other muscles of the body or the mass of the body. Using other muscles to drive hip rotation and then using the rotation to add power to a technique insures the technique will carry the maximum power the body can generate. Hip rotation also increases the speed of a technique.
Hip rotation is based on two principles:
- Summation of forces. Hip rotation reinforces the transfer of mass to into the technique. To properly use the summation of forces in a technique, the movement must be started by the larger, stronger, generally slower, muscles of the body (the hips and thighs) so they will be moving into the target along with the quicker hands or feet together at the moment of impact.
- Stretch reflex.In the stretch reflex, a muscle is stretched immediately before it is contracted so it will contract more forcefully than if it had not been stretched. If the hips start moving first, the lagging leg will be stretched before it moves into the kick.The lower back should have a slight, normal curve. Some women's buttocks protrude further than most males so some instructors try to make these women tuck their hips up further than normal so that their profile looks similar to a male profile. This flattening of the lower back should not be done.
The rotation usually happens around the hip joint that is serving as the center of rotation, not the center of the body. This would be the left hip joint, during a right hand reverse punch. The hip joint around which the rotation is occurring should remain firmly in place or move toward the target. The technique will be weakened if that hip joint is allowed draw away from the target. The hip joint on the punching arm side should still be rotating toward the target when contact is made. The technique will be weakened if the rotation stops before impact is made. The technique will also be weakened if the rotation continues past the point where it was going toward the target. Remember, in a linear attack the hips must rotate into the line of attack.
The pivot point in hip rotation changes, depending upon the situation. It may be at either of the hip/leg joints or along the center line of the body. When the body is stationary, rotation is usually around the body's center line, such as when executing a jab from a front stance. To gain move power in the jab, the front foot may slide forward so the pivot point changes to the trailing hip/leg joint, thus adding more rotation and more power to the punch. When the body is moving, rotation usually pivots at one of the hip/leg joints, such as when executing a trailing leg side kick.
Hip rotation may be described as regular or reverse. In a regular rotation, the direction of rotation and direction of the technique are the same, such as with a reverse punch, jab, or round kick. In reverse rotation, the rotation and the direction of the technique are opposite, such as with an inside-to-outside middle forearm block. Hip rotation may also be used with a lead punch but the lead hip must drive toward the target. The rotation occurs around the rear hip joint.You master hip rotation through regular and constant training. As you become more proficient with hip rotation, the movement develops into an even more powerful and quicker movement called hip snap.
Hip snap is hip rotation but with less movement and more "snap" and therefore, more power. Think of a technique as an arrow. To fire the arrow, the bowstring is pulled back and it bends the bow backward to store energy in it. When the string is released, the energy stored in the bow snaps the arrow forward. Firing a technique operates under the same principle. The hip is twisted backward to store energy that is snapped to apply the mass of the body into the technique.
To practice hip rotation, stand in a parallel ready stance and place both hands on the hips, elbows out to the sides. While looking straight ahead, rotate the hips so that one elbow is pointing forward and the other backward. Do not turn the head or move the feet. Keep the shoulders and hips aligned. Do not let the shoulders reach past the hips for this will result in a loss of power and stability. Now rotate the hips back the other way so the other elbow is pointing forward. Stay upright and do not lean. Ensure the hips rotate on a horizontal plane without any other extraneous movement. As you rotate, use the thighs and other body muscles to add power to the rotation. Tense the entire body, especially the abdomen, at the moment the elbow would be expected to make impact with a target. One way to cock the hip is to make a faking motion in that direction and then follow up with the twist and an attack in to opposite direction. To master the hip rotation, concentrate on using it with every technique.
To improve hip motion:
- Hip and ankle flexibility and strength must be improved so that proper posture can be maintained and proper angles are used at the ankles and hips.
- Notice which muscles in the hips and legs actually cause rotation to happen and learn to use them properly by stimulating them with high repetitions of simple movements.
- Train slowly at first while concentrating on large motions and proper form. Speed up after proper form is achieved.
When punching and blocking, use hip snap in conjunction with the simultaneous retraction of the trailing arm to gain extra power. The action-reaction force gained from retraction is discussed earlier in this topic. When kicking, the hip must rotate and "turn over" into the kick for the kick to attain maximum speed and penetration power.
Key points in the execution of hip rotation include:
- Rotation must be smooth and in one continuous movement, no stops or hesitation.
- Keep the hips level with the floor.
- Do not allow the hips to rise.
- The faster the hip rotation the stronger the technique.
- Remember to use the rear leg to reinforce ship movement and increase total power.
- Shoulders must rotate with the hips, not before or after.
- Keep body vertical, no leaning.
- Both hips must rotate along a horizontal plane, no tilting
- Hips, shoulders, and feet must rotate simultaneously.
- Use hip snap in punches.
- Use hip rotation and hip turnover in kicks.
- Use hip twist in forward movements.
- Lag hip in movement to maintain weight balance.
- Withdrawing the hip joint around which the rotation is occurring.
- Hitting the target with the hand or foot after rotation has stopped.