Strings (tennis)
In tennis, the strings are the part of a tennis racquet which make contact with the ball. The strings form a woven network inside the head (or "hoop") of the racquet. Strings have been made with a variety of materials and possess varying properties that have been measured, such as dynamic stiffness, tension retention, thickness (gauge), string texture (shape of the string), and rebound efficiency.
Follis (ball)
In his testimony, Joan Lluís Vives explains the Jeu de Paume comparing the strings of the racquet from that game, played in Paris with drones gut of the sixth string of a guitar. the demands of a tennis racket stringing regard to the determine the strings of animal intestine are well suited for this use.