In 1874, Major Walter C. Wingfield patented the rules and equipment for what most consider the first version of modern tennis. His rackets were made of heavy wood, with a head size of approximately 60-65 square inches. The first century of tennis saw little improvement in equipment. Rackets became slightly lighter and stiffer due to developments in laminating technology, but the head size remained virtually the same until the 1970’s. Metal rackets were introduced in the 60’s, but it wasn’t until 1976 that Prince released the first popular “oversized” racket, the Prince Classic.
The larger head increased racket power, and gave players a much larger sweet spot. The sweet spot is the part of the strings that is the best place to make contact with the ball. This innovation sparked an incredible upsurge in racket technology. Since then, racket manufacturers have experimented with all sorts of racket head shapes and sizes.
Head size is measured by calculating the total area of the strung area of the racket. Nowadays, the smallest head size produced is 85 square inches, while the largest is around 135 square inches. Though there is no industry standard, modern racket head sizes are typically divided into three categories: traditional (less than 100 square inches), midsize (100-106 square inches) and oversize (over 106 square inches).
The general rule for tennis rackets is the bigger the head, the more powerful the shot. However, with this increase in power comes a decrease in control. A smaller head size will help you control your shot placement, but shrink your power.
Some professionals use oversize heads, but they are mainly intended for beginner players whose muscles are not used to generating most of the power behind their shots. The large sweet spot reduces mishits and provides more consistency in undeveloped strokes. The lack of control is usually not noticeable until a player is refined enough to place most of their shots within a couple feet of their target.
A traditional head size is intended for the advanced player, who is able to produce the power behind their shot with their arm. It is much easier to direct your shots, so players who like to spend a lot of time near the net tend to prefer smaller head sizes. They are also easier for smaller players to maneuver.
A midsize head is a nice compromise between the two, providing slightly more control than oversize, while not sacrificing too much power.
Your style of play will help determine the right head size for you. A power player with strong arms, who likes to hit hard tends to prefer a smaller head size, in order to maintain the maximum amount of control over their shot placement. A finesse player, who likes to focus on returning shots and waiting for their opponent to make a mistake will likely lean towards a larger head size for the larger sweet spot and increased consistency. A combination player that adapts their style to their opponents will probably want an adaptable midsize racket.