- As a Free body Diagram, when hitting the tennis ball in a diagonal motion,
- Your on the balls of your feet
- Your left knee twisting in a lateral rotation
- Your right knee twisting in a medial rotation
- Keep your arms locked in a bent position (L position)
- While twisting your back in transverse plane
- Your arm (the one holding the racket) with stay bent in the L position, but your arm will be tight in that position and will also stay in the same motion which will consist of your shoulder in a horizontal adduction when your back is twisting in the transverse plane. (it's all one motion)
- While twisting, is the same time you will hit the tennis ball with force.