Choosing the right racket can be a daunting experience. With the wide variety of rackets on the market and the potential of the wrong racket negatively affecting your game--not to mention your wallet--it is important to understand the variables that comprise the modern racket.
The main thing to consider in choosing a racket is whether you are looking for power or control.
Players new to the game of tennis generally need a lighter racket that can add more power to their swing. Power rackets are lightweight (8-10 ounces) and feature oversized heads (100-130 square inches); they're generally longer and head-heavy to supply that extra torque in the swing. The power racket is also loosely strung for more power, and the oversized head offers a large "sweet spot" for maximum return on the ball. The trade-off is a lesser degree of ball control. The power racket is suitable for players more concerned with adequately getting the ball over the net, rather than with the nuances of advanced tennis like spin and placement.
Control rackets, on the other hand, are all about ball control. These rackets are for advanced players who can supply their own power to their swing, and prefer a racket that offers more control over ball placement and spin. Control rackets are heavier (11-15 ounces), and feature a smaller, lighter head for maximum maneuverability. Control rackets are tightly strung with thinner beams for further ball control.
The idea is to find the proper balance between power and control. This is where the large selection of rackets on the market comes into your favor. Any combination of these variables can be found to best suit your playing ability and desired improvement.
Probably the most influential racket variable is the size of the head. Larger head sizes create higher speeds of ball rebound and have a larger sweet spot--the area on the racket face where the ball rebound is the fastest and most accurate. A large racket head also dramatically increases the racket's resistance to twisting in off-center impacts. Modern rackets range between 85-135, with around 100 being the most common.
Another key design variation is the width of the racket frame. Increases in the width of the frame increase its stiffness and eventually the speed of ball rebound, since not as much energy is spent bending the racket. The cost of such increases is the transmission of a greater impact shock to the arm.