Marat Safin and David Nalbandian demonstrate the fully coiled position of the two hander. Notice how their chins are overlooking their shoulders, which is a great indication of upper body coil. Notice as well how their shoulders are coiled farther than their waists. This creates an upper body stretch. It is like winding up a spring.

Also notice how their hands are around chest height, and their rackets are pointed upwards at a 45 degree angle. It is important to get this height in the racket because it will aid in timing the shot by lowering the hitting arm and uncoiling into the ball.

Let's look now at how their weight is positioned. Safin has all his weight on his back foot. Nalbandian is in the proces of shifting all his weight onto his front foot. Either way, start with your weight on the back foot. You want to shift your weight on the front foot as you lower your arms.