IntroLinear motion refers to movement along a straight line. As it pertains to the martial arts, it means the weapon moves along a straight line from its starting position to the target.
An exampleThe jab is the simplest example of linear motion. In its most basic form, the rear leg pushes the hips and body toward the target, while the front knee and ankle bend in the direction of the target. Thus the leading side of the body is pushed toward the target. The lead fist (the weapon) is thrust straight to the target with the body mass and muscle forces pushing it.
ThrustingThrusting is directing related to linear motion. In a thrust, the weapon is fired straight at the target with forces from all the muscles involved and the mass of the body all applied to it along a straight line directly to the target. The rear leg pushes the body forward by straightening and thrusting backward and downward into the ground. The faster and harder the leg is thrust into the floor, 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 energy transfer to occur, there must be a tight connection between the lower and upper body; therefore, all the muscles of the torso must be contracted. The entire body is then thrust toward the target, much like a swordsman’s thrust of his or her sword at an opponent.
Let’s examine a side thrust kickThe side thrust kick takes advantage of linear motion to create power. In a lead leg side thrust kick, the support leg’s hip, the kicking leg’s hip, and the target lie on the same straight line. To be effective, the kick must be thrust down that same straight line and into the target. At the moment of impact, the hips should be closer to the target than the base foot to allow the kick to have maximum range and power.
Ideally, linear techniques such as the side thrust kick or punches are driven nearly horizontally into the target. The greater the angle of impact deviates from 90 degrees, the less effective the technique. For a linear attack to a target that is higher or lower than horizontal be most effective, the target needs to be tilted so its surface is perpendicular to the line of the attack. For example, in a board break using a side thrust kick or a punch, the higher the board is held, the more it should be tilted downward to keep it perpendicular to the line of attack.
Let’s examine an uppercutTo be effective, an uppercut needs to be thrust into its target at a 90-degree angle; therefore, it is directed upward into a higher target that is angled downward, such as under the chin or jaw. A common mistake made by beginners is using an uppercut against a vertical surface, such as the torso or a punching bag. When it’s used this way, the fist slides up the surface instead of into it. One of the most effective hand techniques to use on a lower vertical surface, such as the abdomen, is an upset punch where the fist rotates outward instead of inward and is thrust into the abdomen horizontally.
Things to avoid when thrusting
- If the thrust of the rear leg is weak, it’s usually because the head and shoulders are tilted forward. This impairs stability and results in an ineffective technique; therefore, keep the hips, upper body, and head held vertical.
- If the heel of 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 give the technique a little more range.
- If the movements of the hands and feet are not coordinated with the movement of the rest of the body, it is impossible to achieve a focused technique. All the forces generated in the body must arrive at the point of impact at the same time.