The application of force to the strings by a machine to achieve the desired playability of the string bed. Most modern racquets will be strung somewhere between 40-70 pounds (18-32 kilograms) of tension. Typically a racquet will feature a recommended tension range somewhere near the throat of the racquet. The closer to the top of the range, the more control and less pop a player will experience. A lower tension will provide more power, but also less feel and control. The middle of the recommended tension range is a good place to start on the quest for the perfect racquet tension. From the time the string is installed, it will begin to lose tension, often 10% or more within the first 24 hours before stabilizing for a time. As the tension continues to drop, elasticity also decreases, forcing the player to provide more of their own power for the same results as a freshly strung racquet.

This is the diameter of the string, commonly expressed in millimeters and/or gauge numbers (the higher the gauge number, the thinner the string, and vice versa). Thinner strings tend to provide more power, feel and spin potential than a larger diameter string of the same type, although the thicker string will provide more control and durability.

If you want to maximise your performance, be sure to regularly restring your racquet. The general rule for restringing is at least every 6 months, or as many times in a year as you play in a week. So if you play 3 times a week, you should be restringing at a minimum of three times a year.