Ive seen a lot of top amateurs hitting and ive seen a common theme. Most of the amateurs are using a lot more energy than the pros. I know theres exceptions to the rule like players like Gonzalez and Tsonga, but is it all about technique and energy for the majority of the upper echelon players. Its hard for me to understand but look at players like Murray, nalbandian, and safin that make the game seem so effortless, but theres exceptions and relentless top pros like David Ferrer that kind of throw the whole technique arguement out of the water. For instance I watched a college match and the technique was terrible, its like they were trying to hit as hard as possible, then you have a player like Murray who has that great footwork and technique. Whats the biggest difference between top amateurs and pros?