Glossary
When learning about strings and their characteristics, you’ll encounter a range of specific terms and technical language. Below are some commonly used terms:
Actual Tension – The true tension in a strung racket. It’s typically lower than the reference tension due to string relaxation (known as “creep”). Tension loss varies depending on the string type, stringing machine, racket head size, and the skill and technique of the stringer.
Bite – Thinner strings offer less surface area, allowing them to grip the ball more deeply on contact. This enhances control and is referred to as string “bite.”
Dwell Time – This is the amount of time the ball remains in contact with the strings during impact.
Dynamic Stiffness – A measure of how much a string deforms under rapid impact, such as when hitting a ball. A stiffer string stretches less, while a more elastic one stretches more and returns greater energy to the ball. Dynamic stiffness, often associated with elasticity, is measured by the force (in pounds) needed to stretch the string one inch. Natural gut typically has lower dynamic stiffness than nylon or synthetic alternatives.
Gauge – Gauge indicates string thickness. A higher gauge number means a thinner string.
The “L” in gauge numbers like 15L or 16L stands for “light.” These designations originally aligned with American Wire Gauge (AWG) sizes but have since evolved to represent diameter ranges rather than fixed values.
Hybrid Stringing – This method combines a stiff, durable string (like polyester or Kevlar) with a softer string to balance performance and feel. Typically, the main strings are polyester/Kevlar, while the cross strings are synthetic or natural gut.
Proportional Stringing – A technique where each string is tensioned according to its length, ensuring uniform stiffness across the stringbed.
Reference Tension – The target tension set on the stringing machine; this is the nominal tension used during the stringing process.
Relative Tension – At the same reference tension, thinner strings stretch more than thicker ones, effectively making them feel tighter. This effect is called “relative tension.”
Soft – A soft string absorbs more impact energy, reducing stress on the racket and the player’s arm. These strings typically have low dynamic stiffness.
String Creep – A slow, molecular-level loss of tension over time. Rackets can lose around 10% of their tension within a day of stringing, even if unused. Continued use accelerates this tension drop.
Sweet Spot – The area of the stringbed that produces minimal vibration and transmits the least force to the hand on impact. It’s generally near the center of the stringbed. Contrary to popular belief, this isn’t where the most power is generated—that point lies closer to the racket’s throat, near its center of mass.
Tension – Measured in pounds (lbs), though sometimes in kilograms (kg), this refers to how tightly the strings are pulled during stringing.
Trampoline Effect – At lower tensions, strings deform more on contact and spring back quickly, adding power to shots. This effect is reduced at higher tensions, where the strings stretch less.