When the ball descended through her point of contact , she needed tremendous racquet head acceleration to meet the ball in the optimal point of contact range .
It was this racquet head speed that gave her all her power and direction on the serve .
When the ball descended through her point of contact , she needed tremendous racquet head acceleration to meet the ball in the optimal point of contact range , and it was this racquet head speed that gave her all her power and direction on the serve .