Strings, grips and dampeners.

Tennis: strings in the ITF Rules of Tennis 2026

The string rules in the 2026 rule book, as recorded for this site, concern the strung face rather than the string itself. They sit in Appendix II(b) and the Rule 4 cases:

• The hitting surface is a flat pattern of crossed strings, alternately interlaced or bonded where they cross, generally uniform and no less dense in the centre than elsewhere, and both faces must play the same (Appendix II(b)).
• Only one set of strings is allowed on the hitting surface (Rule 4 Case 1), and strings on more than one plane are not generally uniform and flat (Case 2).
• Vibration-damping devices, often called dampeners, may go on the strings but only outside the pattern of crossed strings (Case 3). Appendix II(d) also allows attachments used to limit wear and tear or vibration, reasonable in size and placement.
• A player who accidentally breaks strings during a point may keep playing with that racket unless the event organisers specifically prohibit it (Case 4).

The ITF's technical note on strings (November 2019)

Separately from the rules, the ITF published a technical note called "Strings" in November 2019. As the ITF describes them:

• Materials: natural gut is the most elastic of the common string materials (it stretches most for a given load), Kevlar is the stiffest commonly available string, and nylon and polyester lie between them.
• Gauges: string diameters run from gauge 19, the thinnest (1.00 to 1.10 mm), to gauge 15, the thickest (1.41 to 1.50 mm), with half sizes marked by the letter "L".
• At impact: strings and ball both deform heavily, the strings recover and the ball leaves within about 5 milliseconds, and the strings return around 90 to 95 percent of the impact energy, far more than the ball does.
• Over time: strings lose tension. The note also says that, scientifically, stiffer strings generate larger impact forces.

Polyether ether ketone (PEEK) is also marketed as a string material. Ashaway, a string maker, claims PEEK is the synthetic closest to natural gut in dynamic stiffness; that is the maker's claim.

Pickleball: grips and tape (2026 USA Pickleball Rulebook)

Pickleball paddles have no strings. Rule 3.D.6 lists what a player may add to a certified paddle, and grips are among them: the maker's interchangeable grips and faces, grip-size inserts and grip wrap, along with edge-guard tape, weighted tape, weights in the maker's integrated weight system, name decals and handwritten pen identification or autographs. Aftermarket graphics are not allowed. Rule 3.D.7 says decals and tape on the face may reach no more than 1.0 in (2.54 cm) above the top of the grip and no more than 0.5 in (1.27 cm) inside the outer edge or edge guard. The Equipment Standards Manual, Revision 3.0, says vibration dampers are acceptable.

Padel: attachments and the wrist cord (FIP Rules of Padel, from 1 January 2026)

Padel rackets have a perforated face, not strings. The racket rules allow only attachments that limit deterioration or vibration or distribute weight, reasonable in size and position, and no reflective surfaces or sound elements that could alter normal play (item 8). The racket must have a non-elastic wrist cord of at most 35 cm fixed to the handle, and its use is obligatory (item 9).

Squash

The World Squash Singles Rules 2025 send racket matters to the WSF's separate racket-specification page, which could not be read for this site. No squash rule on strings, grips or dampeners was recorded, so none is stated here.

Badminton: strings and the hand cord (BWF Laws of Badminton)

The Laws regulate the stringed area's shape and size, not the string material. Law 4.2.1 requires a flat stringed area of crossed strings, alternately interlaced or bonded where they cross, and Law 4.2.2 sets its maximum size. Law 4.3.1 allows attachments used solely to limit wear and tear or vibration, to distribute weight, or to secure the handle to the hand with a cord, each reasonable in size and placement. No governing-body or standards-body source on badminton string materials was found.

Grips across the five sports

None of the rule books read for this site describes grip materials. The rules only say which attachments are allowed, as above. Grip sizing and fitting are not covered on this site.