Strings (tennis)
The material used in tennis string can significantly affect a player's performance, and even health. Several materials are used to make tennis strings. They vary in terms of elasticity, durability, rebound efficiency, tension holding capability, and manufacturing cost, among other considerations.
Racket (sports equipment)
Weights of a racket also vary between unstrung and strung. Until the 1980s, rackets weighted at "medium" were produced. "Heavy" rackets were produced during the height of the wood era (e.g. the 1960s), very sparingly. The "medium" weight is heavier than any of the rackets produced since it was discontinued by companies. Many professionals added weight to their rackets to improve stability. Many continue to do so. Pete Sampras added lead tape to make his racket have a weight and Venus Williams is known for using a frame modified to be quite heavy, in terms of the recent times average. By contrast, Andy Roddick surprised many when he said he used a stock Pro Drive series model, series of racket which was light when compared with the rackets used by most top professionals. In both recreational and professional tennis, the trend has been away from heavy rackets and toward lighter rackets, despite the drawbacks from light rackets, such as increased twisting. Lawn tennis rackets originally flared outward at the bottom of the handle to prevent slippage. The rounded bottom was called a bark bottom after its inventor Matthew Barker. But by 1947, this style became superfluous. More mass gives rackets "plow through", momentum that continues once the player has managed to get the racket into motion and which is more resistant to stoppage from the ball's momentum. This can give the perception that the racket produces shots with more power, although this is complicated by the typically slower stroke production. Higher mass typically involves a slower swing but more energy to execute the swing. More mass also provides more cushioning against ball impact shock, a source of injuries such as tennis elbow. However, high racket mass can cause fatigue in the shoulder area. Typically, it is safer for the body to have higher mass. More mass, additionally, provides more stability. It makes the racket more resistant to twisting forces and pushback. The drawbacks are that heavier rackets have lower maneuverability (reducing reaction time) and require more energy to move. As a racket gets heavier, the player finds it increasingly difficult to do fast reaction shots such as quick volleys and returns of serve. However, the additional mass can help with return of serve, in particular, by making the racket much more resistant to twist from a high-powered service. Light rackets have the additional drawback of making it easier for beginning players to use inappropriate wrist-dominant strokes, which often leads to injury. This is because poor stroke mechanics can be much easier to produce with a lightweight racket, such as in using one's wrist to mostly swing the racket. An extremely typical mistake beginning players make is to choke up heavily on the racket (to try to compensate for twist from a light racket, as well as too high racket angle upon impact) and use the wrist too much. The only professional well-known player to have had success with a strongly choked-up grip is Zina Garrison.