Power comes from the hips, whether you are executing a hand technique or a foot technique. If your hip movement is loose, powerful, and quick, your techniques will have the same attributes.

When executing a stepping fore fist punch, as you push off the rear leg, both hips are pushed forward in a linear motion. If you let the abdominal muscles rotate the hips about the vertical centerline of the body, more power is applied in the direction of the rotation and it helps transfer some of the linear motion of the leg push into the rotational motion of the hips. As the hips rotate, the torso and shoulders also rotate, all of which contribute to the overall power of the punch as rotational motion is transferred into the linear motion of the punch. The linear and rotational forces of the body's mass combine to concentrate maximum power into a technique. To add more rotational power to the hips, such as when executing a reverse punch, the heel of the pushing foot rises and the foot drives forward off the ball and toes.

To see the power that hip rotation adds to a technique, try this. Hold your lead arm in a hook punch position: arm held shoulder high, arm parallel to floor, elbow bent, with a horizontal fist pointed inward. Without moving the arm or shoulder muscles, hit a target with the fist by snapping the hips in a twisting/snapping motion to drive the fist into the target. Notice the "jolting" power with which the fist hits the target. Notice that, although not slow, the motion of the punch is not very quick.  Now strike the target with a hook punch motion that uses the arm and shoulder muscles without using any hip twist or snap. Notice the power is still great, but there is no jolting power. However, the punch is very quick. Now strike the target while combining the two motions. Notice the quick, jolting power of the technique. If you had to get hit by a hook punch, which method of punching would you rather the attacker use?

Hip snap is not unique to Taekwondo or karate, boxers have used it for over 70 years. Sam "The Tar Baby" Langsford told his young boxers to "get them hips into your punches" and Jack "The Manassas Mauler" Dempsey often referred to the importance of the waist twist when teaching his "shoulder whirl" technique.

Hip rotation is the driving force behind hand and leg techniques, but it is especially true for kicks. Many kicks, such as the crescent kick, are useless if the hips do not drive them. Always concentrate on hip movement during kicks and strikes.

In the Theory of Power section of his manual, Encyclopedia of Taekwon-Do, General Choi Hong states that maximum kinetic energy of force is obtained from maximum mass and speed and it is all important that the body mass be increased during the execution of a blow. He thinks that this may be accomplished by combining two methods, hip rotation and the sine wave principle. As will be explained below, hip rotation adds to power, while the sine wave principle is based on false logic and is wasted motion.

How to Perform Hip Snap

When performing hip snap, think of the motion more as a delayed hip movement than as a rotation around the vertical axis of the body. For example, when stepping forward in a front stance with a straight punch, instead of thinking about hip snap as a rotation of the hip during the punch, think about the hip lagging behind the leg during the step and then snapping back into position just as the foot touches the floor.

Hip Snap/Hip Vibration

Hip snap occurs as the hip of side executing the technique snaps toward the target and then recovers. This occurs as the hips are relaxed, snapped into the technique, tensed on impact, and then relaxed as allowed to return to the normal position. Sometimes there is a cocking of the hip before it snaps.

Hip vibration is a term used to describe the movement of the hip during hip snap. The hip cocks, snaps forward, and recoils in short quick vibrating motion.  The recoil part of the vibration serves as a counter balancing motion, helping you maintain balance without shifting the center of mass in the direction of the strike.  Hip vibration is subtle movement that takes hours and hours of training to perfect. The most common errors in the use of hip vibration are throwing the shoulders forward, not coordinating the timing of the hips and hands, and moving the hips too slowly.

Hip Snap versus Winding

What is winding? Winding is a technique used when in International Taekwondo Federation (ITF) style punching. According to the ITF Theory of Power, to obtain maximum power there should be a forward and and then downward momentum associated with a punch (Encyclopedia of Taekwon-Do, Vol. 2, p. 33, 38).  Winding involves lifting the punching side heel prior to the punch (forward motion) and then dropping it (backward motion) as the punch is executed (winding is also know as knee spring) (Encyclopedia of Taekwon-Do, Vol. 3, p.16). The motion is sometimes accompanied by upward circling of the punching arm as it is pulled back and thrust forward. When winding, the body moves slightly forward and then drops backward as a technique is fired.

Just as with the sine wave (examined below), winding requires some movement other than those related to the actual attack. Only an inexperienced fighter will cock a punch before throwing it. Although it may add power to the punch, it also adds time and it telegraphs intention to punch. Any motion that is not directly related to the actual attack wastes time and informs opponent of your intentions.

Sometimes, people accept some core belief and then search for justifications for the belief. In this search, they accept anything that sounds good and supports the theory, while rejecting anything that refutes the theory, even if it also sounds good. When evaluating any theory, not just Taekwondo theories, do not except unsupported rationalizations. You do not need a PhD or a 10th degree black belt, just use common sense and rational reasoning.