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Pracitse the movement slowly and with large movements. Then acquire speed not by moving faster, but bydecreasing the range of movement to the point where the circles become invisible t othe eye. In fact, you will sound fast and powerful, but visually you will look like you are not moving too much at all, in an easy and effortless way.This is difficult to describe in writing, it has to be demonstrated. I have tried to do it in this more detailed post:
This is exactly how my teacher describe it to me in the beginning. Especially when we started with scales. I solved the tension problem just like that, starting with large circular motions, and slowly making those motions inperceptible. As Bernhard said, it's very easy to demonstrate, very difficult to describe in writing. -Paul