Footwork in randomly changing distance
Situations that include randomly changing distance are the constant element of highly interactive environment in sports. The change may include random extension or shortening of the distance, as well as the change of movement direction/body positioning. In all these situations the effective reaction requires flawless timing of footwork.
Ability to effectively adjust to random change in the distance can play decisive role in various situations in different sports. It takes place while defending the net in soccer, avoiding the impact in football or landing finishing technique in fighting sports. In this article we will use the game of tennis as an example and focus on the situation where the ball’s trajectory and its’ projected traveling distance gets altered as a result of hitting the net.
The change in the distance can be anticipated but, by definition, in randomly changing situation should not be looked forward to. The word “random” is not to suggest the events are fully unexpected but rather refers to the limited (if any) predictability of their occurrence at present. In any case, optimal performance relies on the ability to effectively react whether the change takes place or not.
Illustration 1 shows the tennis ball hitting the net which changes its’ projected course. As a result, the ball travels through the shorter than originally anticipated distance, which automatically extends the distance the player has to cover in order to hit it (AD- additional distance to cover). It is important to understand the player is already in motion and to effectively respond to the change they need to react with no delay. Considering the mental processing’s effect on timing, there is no time to think and consciously decide the next step here. Effective reaction to random distance change requires the player to avoid unnecessary pause or slowing down and actually increase the energy while reacting to the change. This is rather simple in more or less stationary mode but can be more challenging while executed with the body already moving with speed.
While analyzing the footwork in randomly changing distance it is important to understand the reaction point – the point where the contact with the ground is made to physically adjust to the new distance. In our example it is the point of push off, at which we generate additional energy needed for an extended effort. The choice of which leg to engage is made simultaneously and depends on legs’ temporary energy levels.
This “energy preference” is a foundation of TER (transferred energy ratio) reaction model. TER uses each leg’s individual energy level at the moment of reaction as a base for optimal physics and timing of the movement. The model applies effectively to both stationary and dynamic environment and fully utilizes ground reaction forces improving acceleration, balance and level of adjustability. TER reaction has a vital impact on reaction timing by synchronizing the mind, the change in the distance/direction and the corresponding action of the feet.
TER reaction is an optimal choice for situations with randomly changing distance (that includes our tennis example). Technically speaking, it uses 50% energy factor as determining agent. This means in moving forward we have two possible scenarios – one with front leg generating more than 50% energy at the reaction point and the other with front leg generating less than 50% at the moment of reaction. Depending on the energy factor, we engage the leg that is a better fit timing wise and allows us to increase the energy in the process as well. This means in each of these two cases optimal footwork reaction will look different.
Let’s have a look at illustration 1. The two green dots on the left side indicate possible reaction points – RP1 and RP2. As you can see, two reaction points are separated by the 50% line mark. The points RP1, RP2 indicate where we physically initiate the reaction (contact with the ground) in relation to the energy already transferred to the front leg. Let’s consider RP1 – the case where reaction point lies below the line indicating 50% mark. This is a case when less than 50% of energy transfer to the front is completed. In such instance, completing the step as originally planned may not lead to successful finish. Doing so will be less beneficial than redirecting the energy back, which will actually let you adjust the distance and timing accordingly.
One of the reasons why redirecting the energy pays off in such situation is that it gives the player chance to adjust the amount of ground reaction forces. This is important because the forces put to action at the start may not be sufficient for extended distance (not enough spring and not enough support from the ground). Failure to rapidly increase the energy leads to delay in time and at least partial loss of balance. Moreover, it has a bad effect on the ability to adjust in case another change occurs.
In one of the future posts I will share more details on why and how the energy redirecting works.