This step is conducted at the sixth and seventh lesson.
In this lesson the instructor has to use another instructor or another skilled player to serve as an assistant instructor.
It starts when the assistant instructor passes the balls towards the trainee.
The trainee is being aware in advance to the possibility that he will be required to "freeze" his motion upon a `STOP` call by the instructor standing behind him. Another possibility is when the instructor from behind, simply grabs the trainee during motion and let the ball fly with no response. Each `stop` or `grab` is accompanied by an explanation describing the part which is biomechanically wrong. The instructor also has to offer a movement correction to the extent the trainee can perform, judged by the instructor.
To illustrate the problem of a lack of balance when striking, the instructor needs to enable the trainee to hit the ball and immediately after impact to push him slightly in order to illustrate the state of improper balance, during impact.
To illustrate the faulty end location of the swinging arm, the instructor has to enable the trainee to perform the strike and grab his wrist a fraction of a second later and thereby demonstrate the error.
In order to examine the quality of preparation for the strike, striking hand has to be grabbed and checked for "wrist locking" quality, handle grip quality, range of arm movement towards the back, racket head angle to the floor (according to grip type) and armpit angle.
In order to examine the state of the spine and scapulae, the trainee must be stopped almost before impact to demonstrate the rate of unnecessary bending of the spine and the lock of the scapulae bones, explaining that shoulder shrinking is not allowed.
It should be emphasized to the trainee in advance what is going to occur physically. An early explanation enables understanding and acceptance of all those touching and grabbing.
The initiated breaks of the striking process create a good learning curve of body condition while doing it. It also allows a good understanding of the problem by the trainee's partner.
In case this practice brings the desired results within the first hour, it's possible to get to the next stage. In case of poor advance, it is imperative to repeat the process with shots made at the same velocity and angle as much as possible in order to achieve better results.