When I watch some of my friends play, i can see them straining muscles and just trying to smack the ball by hitting it hard with their muscles. However, when I see the guys on the tennis team play, they hit harder without all that straining of muscles because they have the technique down. How do some players create so much pace on a flat dead ball sitting in the middle of the court without hitting home-run? How long does this technique of hitting the ball effortlessly usually take? better yet, how ?