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.
Tennis ball
The ITF's "Play and Stay" campaign aims to increase tennis participation worldwide, by improving the way starter players are introduced to the game. The ITF recommends a progression that focuses on a range of slower balls and smaller court sizes to introduce the game effectively to both adults and children. The slowest balls, marked with red, or using half red felt, are oversized and unpressurized, or made from foam rubber. The next, in orange, are unpressurized normal sized balls. The last, with green, are half pressured normal sized.