[Retracted] Remote Evaluation System of Tennis Batting Action Standard Based on Acceleration Sensor

Table 1

Evaluation index and evaluation standards of tennis batting action.

Evaluation indicators	Evaluation criteria
Mobile time C1	A move that begins when the ball is not over the net and is hit by an opponent
The degree to which the pace moves into position C2	Able to reach the hitting position, steady body weight, and accurately hit the ball
Overall movement rhythm C3	The lead shot, there is a momentary pause; hit the ball coherently and fluently with the swing
Global barycentric stability C4	Keep the center of gravity steady and unchoppy from the start to the end of the shot
Lead the racket to end position C5	The racket swings to the side of the body; the racket holder arm is slightly bent; and the racket head extends to the maximum back of the court
Racket back time C6	When the opponent hits the ball, the racket is drawn when the ball is not over the net
Rhythm of batting swing C7	Instant acceleration and a consistent, fluid swing
The best position for hitting C8	The height in front of the pivot foot at waist level
Direction of strike C9	Hit the ball in the planned direction