Understanding tennis racket stiffness

Stiffness is measured by the RA (Frame Stiffness) index. This index indicates how much the frame deforms upon impact:

Stiffness Scale (RA) and Playing Characteristics

Type	RA Index	Characteristics
Very Flexible	< 60	Maximum flexibility, high comfort
Flexible to Mid	60–65	Good compromise control / comfort
Stiff	66–70	Natural power, less forgiveness
Very Stiff	70+	Maximum explosiveness, more vibrations

The RA measurement quantifies the frame's deformation upon impact.

The direct impact on your game

• Stiff racket

  • Increased natural power ("trampoline effect")
  • Reduced contact time → more delicate control
  • Stronger vibration transmission

• Flexible racket

  • Less intrinsic power
  • Superior control thanks to "pocketing"
  • Playing comfort, shock absorption

How to choose according to your profile?

For the beginner / intermediate player

• Choose a flexible to mid (60–65 RA) racket
• Helps develop technique → longer contact time
• Better comfort and joint protection

For the seasoned competitor

• Opt for a stiffer (66–70+ RA) racket
• Increased stability and immediate power
• Reserved for physically strong players

According to playing style

• Puncher → stiff frame
• Touch player → flexible frame
• All-rounder → mid RA

Myths & Realities

“A flexible racket is not powerful”
False : a player with high arm speed can generate a lot of power even with a flexible frame.

“Stiffness is the only comfort factor”
False : string, tension, balance, and weight also play a major role.

“All pros play with stiff rackets”
False : some prefer flexible frames for touch and arm protection.

The RA index is just one benchmark among others: it should always be read in conjunction with the weight, balance, and head size to understand a frame's complete behavior. To compare stiffness levels, from flexible frames conducive to pocketing to stiffer models sought after by competitors, consult our tennis racket comparison and refine your choice according to your playing style.