We can see in this video that his base is very narrow on both Forehand and Backhand, so he is a good player due to his upper body strength and timing, but gets little power from his legs, which  prevent him hitting a heavy ball. Also he will be slow off the mark because playing this high up, (more or less with straight legs) he will struggle to push off with any real power, so his first step running for the next shot will be small.

You will have noticed in the video the difference of Andy Roddick's wide base and a narrow base of Tim. Below is a picture of Anna Fitzpatrick with a wide base. A wide base is necessary for the following reasons:

• Much more power to explode into a Forehand

• Better balance before and after the shot

• Ability to push off with power to get to the next ball

Further details and in depth explanation of the different sources of power in tennis can be found in our Biomechanics DVD.