Every time a technique is completed, the grip will change slightly, which is not static. For example, hanging ball means that we need to rotate the racket face with our thumb and forefinger in time to complete the friction and hanging ball technique. So don't hold the racket too tightly when practicing the eight-character exercise.
There are two ways around the eight characters. The first one is mainly about the wrist, and there is no need to distinguish between forehand and backhand. The main exercise is the hand's familiarity with the beat, which can increase our feel. The second type is forehand backhand backhand turn, which is more difficult than the first type. At the beginning, make a circle with 20% to 30% strength first, and don't think about exerting strength. Practice 200 times a day, 10 day, and the effect is obvious.