What happens to a tennis ball during impact?

According to the USC website (refer to the link, below):

"The three components in the system of ball-racket interaction are the ball, the racket frame, and the strings. During impact, all three components deform to some degree; such deformation is caused by the energy transferred amongst the three components. The ball carries kinetic energy and transfers some of it to the racket frame and strings upon impact. Some of this transferred energy is given back to the ball, allowing the ball to bounce back."