Racket angle at contact and trajectory
The perfect technic is the one that generates the highest power with the least effort, with total control. From a scientific view, the perfect bio mechanics or technic of the perfect stroke is the one that generates the best strength vectors maintaining the body balanced, with the best racket/ball contact angle, the correct racket trajectory pushing the body weight in the desired direction. As we have exposed on past posts, the best way to produce power is to do a fine and stable back swing. To have the highest probability to hit the ball at the sweet spot of the racket, the racket angle at contact must be as close as possible to perpendicular to the direction the player wants to drive the ball. Finally, after contact, the racket has to maintain the same direction of the drive. After years of experience and measures in court, the best way to reach those parameters is to have a round back swing, with an eastern grip and a follow through on the same direction of the drive. Some may ask about top spin. Instead of pulling the racket up, the player has to use an arm pronation. Then the amount of top spin will depend only on the resulting angle formed by the lowest point of the back swing and the point of contact. On the video, Nadal is doing a nice back swing, dropping the racket head below contact, making an outside rotation of his arm to compensate his semi-western grip to reach the perfect angle of contact, and finally, moving the racket head forward using arm pronation.