It’s the amount of energy transferred to the ball after the impact. The strings usually return 95% of the energy, the ball returns 55 to 60% of energy. This means that the softer strings will minimize the amount the ball is deformed and enable it to retain more energy to generate greater power. MORE POWER = more speed with less effort.
It’s the player’s perception of where he can place the ball with the desired trajectory due to the strings’ influence. It depends on three parameters: outgoing speed of the ball, outgoing initial angle of the trajectory and spin. The combination of these 3 parameters generates different trajectories with different levels of control.
It is the rotation given to the ball by the strings after the impact with the racquet. It depends on both the movement and the snap back of the main strings and on the friction between the string bed and the ball. The faster the speed with which the strings snap back, the higher is the ball’s rotation, and the greater is the amount of spin generated. Higher spin means more curved trajectories.
The player’s perception of the impact between the racquet and the ball, and it’s immediate aftermath, is affected by:
— Vibration Dampening: the capability of the string to reduce the vibrations quickly.
— Impact Comfort: the amplitude of the initial “shock” (hard or “crisp” till soft feeling). —Sound: high or low pitch
Two types of durability are identified Resistance to WEAR / notching: it depends on the friction between the main and the cross strings TOUGHNESS = ability of the string to absorb energy during the impact with the ball without snapping.
It’s the feeling of the players allowing them to change pace and positioning of the ball. Touch is related to the vibration feedback profile from the string bed. Every string has its own characteristics and perceived feedback which suits players in a variety of ways.