There is a wide variety of racket designs, although the badminton racket size and shape are limited by the Laws. Different rackets have playing characteristics that appeal to different players. The traditional oval head shape is still available, but an isometric head shape is increasingly common in new rackets. Various companies have emerged but Yonex of Japan and Li-Ning of China are the dominant players in the market. The majority of top tournaments are sponsored by these companies. Every year new technology is introduced by these companies but predominantly, all rackets are made of carbon graphite composite.
Regardless of the number of games and sets in a match, players must continuously rotate sides when the total number of games in a set is an odd number. For instance, if the total game score in a set is 3-2, simply add 3 + 2 = 5. Since 5 is an odd number, the players rotate sides prior to starting the next game. If the total game score in a set is 5-1, simply add 5 + 1 = 6. Since 6 is an even number, the players do not rotate sides.
Tennis is an Olympic sport and is played at all levels of society and at all ages. The sport can be played by anyone who can hold a racket, including wheelchair users. The modern game of tennis originated in Birmingham, England, in the late 19th century as lawn tennis. It had close connections both to various field (lawn) games such as croquet and bowls as well as to the older racket sport today called real tennis. During most of the 19th century, in fact, the term tennis referred to real tennis, not lawn tennis.