Here is where the rubber hits the road. Now you use your Figure 8 hip rotation to power your arms and hit the ball, completely upending the way you think of your strokes. You will never want to go back to your old strokes again.
The Sine Wave refers to the waveform in your arms that starts with your Figure 8 hip rotation. This wave never acts independently of the hips but is a function of the hips. The benefit here is that the motion always leads to a graceful, effortless, fluid stroke. You are not “muscling” the ball since the energy emanates from your core.
This waveform in your arms, like any wave, is rounded. As a player, you want to hold onto this roundness where your arm bends first in a
concave shape and then a convex shape. Now the magic: as your arm travels out to the ball, it bends in a convex shape with the strings laying back. You connect with the ball here. The ball lays into the strings as though your racquet head is a mini-trampoline, which then sends the ball back out. We call this “bumping the ball.” You press so much air into the ball this way that you will be amazed at how well this works and how little effort you need. If you do this properly you will even get pop on the ball. You'll love the sound and feel of the hit.
An easy way to understand bumping the ball is to think of the inside-out forehand, which is nearly always a player's best shot. You run around a backhand and send it back as a forehand. It is nearly impossible to do this without laying the racquet head back to meet the ball.
So here is the Nonlinear Tennis formula for the Non-linear Game, unlocking the secret to playing your best: your arm goes from concave to convex as it expands out towards the ball, and then the racquet bumps the ball at the 45-degree angle, pressing air into the ball. You are performing a “standing wave.”
This Non-linear Game formula is operable for all the strokes and is a particular boon for learning an efficient and graceful serve. It helps players understand that the serve
motion is largely a function of the lower body rotation. In fact, at Nonlinear Tennis we teach the “fishtail serve,” a remarkably effective way to get the feeling of a relaxed, full body serve - kind of like shaking an apple tree to get the apples to fall. The player rotates his lower body in the Figure 8 motion and allows his arm to ripple back and forth from concave to convex, much like a fishtail. The core motion of the hips informs the arm motion. Once you add the ball, things fall into place nicely. The arm goes from concave to convex and at that point the strings lay back and grab the ball for the hit.
This understanding of the Sine Wave should simplify your practice of all your strokes and help you play better and enjoy the game more than ever.