Punch Physics

Taekwondo punches are "focused" to terminate several centimeters within the body being struck, as opposed to the follow-through punches used by the untrained. There are scientific reasons why focused punches are better than wide swinging, follow-through punches.

If contact is made a some point during a wide swing, significant torque will be produced that may throw the puncher off balance. Also, if contact is made during the follow-through, then energy will be transferred to the target via pushing rather than by deformation. Pushing generally does less damage than does deformation.

In a standard Taekwondo punch, the fist begins at the hip and terminates with the arm fully extended and the fist at shoulder height. In a graph of the velocity of the fist as a function of its position (measured as a percentage of the total arm length) you will notice that the maximum velocity is attained at about 75% of the distance to the stopping point. This corresponds to roughly 10-14 cm. Thus, by focusing the punch several centimeters inside the target, the Taekwondo punchers ensure that they make contact closer to the point where the fist has its maximum velocity. This maximizes the potential for damage.