Choice Reaction, Part 7

The previous examples just scratched the surface. An in-depth analysis includes much more than just visible patterns to avoid, reduce or optimize choice reactions times. Visible patterns are just one source of information. For example, rules in sport allow further conclusions. An analysis of mechanics and dynamics or background information on certain effects in motor control adds to the variety of options. The following example offers a glimpse at the possibilities. The analysis and synthesis tools used are not explained in detail. The background is kept short to put the concentration on the interesting aspects. The focus lies on the comprehensibility and not necessarily on the usefulness for a specific domain. It’s all about the thinking process.

This example is based on speed, not necessarily force. So, imagine a simple side kick. We start with the posture with both feet are set parallel to the opponent. A beginner would start by establishing some body tension, followed by shifting his balance to one foot to free the other foot from his body weight. Furthermore, in order to compensate for the additional loss of balance, he would move his arms in an opposing pattern to the kick, maybe even lowering an arm. Additionally, the leg itself is moved rather stretched out. Well, as a summary, a tree diagram is always a good start.


As you can see, there are various patterns for an opponent to conclude the following action. The goal for this example is the process for optimizing some of the aspects. First of all, the buildup of body tension is a pattern that usually allows the conclusion that something will follow within the next second: remember causality. We start by adding a pause between the buildup and the subsequent kick. It is usually advantageous to have basic body tension that can be used as a head start. This basic tension can be maintained until the planned movement is initiated.


The next problematic pattern is the early body shift. This pattern derives from the loss of balance if one foot is raised without countermeasures. Please take a look at the following sketch. The center of balance induces a certain force while the leg is being raised. This is felt as a loss of balance. A suitable approach from bio-mechanics is an additional counterforce from the kicking leg into the ground. This way, the two patterns, losing balance and lifting the leg, are merged into one pattern. This saves some time while adding a little surprise for those unaware of this possibility.






The rather wide movement of the arms can be reduced by using body tension. Lifting the leg and moving it forward requires a specific torque in the body. Using your arms to offset this torque feels more natural. It is difficult to explain this approach in words. The following sketch may not be so understandable. Give it a try – cross your arms behind your back. This way, they cannot be used to build up the required torque. Now kick slowly and try to concentrate on the opposing shoulder. Exaggerate and move your shoulder a bit forward while kicking. Do it slowly to get a feeling for it. After some time, you should get the hang of it. Now, the counter-torque of the arms can be reduced. A barely visible twisting of the upper body should be enough to counter the required torque. This approach is derived from bio-mechanics and the possibility to generate and exchange torques. It reduces visible patterns and thus makes it more difficult to guess the resulting alternatives.





Another approach is derived from a combination of bio-mechanics and some control engineering. Building up a movement from scratch takes some time. The actual condition must change from one state to another. This takes time, like starting an engine. The torque is not available right from the start. Here, transferred to movements, it means that every movement from an idle state takes time to unfold. One approach is to construct opposing body tension to the intended movement. This way, the external view of the body appears still, but internally the torques are ready to unfold. An example would be an automatic transmission in a car. Release the brake and the torque is available instantly. The following sketch outlines the principle. Releasing torque is faster than building up torque from scratch. The pattern of unfolding the movement is faster this way.


A last approach accelerates the kick. The first approach uses an outstretched leg. From a biomechanical view, it is faster to move a bent leg then an outstretched leg, since the inertia is reduced. This is used by figure skaters (spinning, with arms held tightly against their body) or sprinters (bending a leg while moving it forward ). Additionally, this changes the pattern of the kick and the effects on the subsequent alternatives.



As you can see, the kick can be optimized for speed using different approaches. The choice of the approaches and their usage depend on the boundary conditions of each situation. It is still a long and complicated way to freely apply these things. All in all, an opponent´s reaction to an optimized kick is worsened due to the changed patterns and the faster execution. From that point of view, the “incorrect” posture at the start is a plus. Such a kick is not really expected in such a combination.

The post was published 16. May 2014 related to the category Miscellaneous and tagged with , .