Tennis racquet stiffness

The stiffness of a tennis racquet corresponds to its capacity to deform when hitting the ball.

The value of the stiffness is expressed in Rahmen (Ra).

The higher the value, the stiffer the racquet is.

A tennis racquet is considered as flexible when its Rahmen value is between 55 and 60, semi-stiff when the value is between 62 and 67 and stiff when the value is 67 or above.

This page provides information about the stiffness of the tennis racquets, a notion with many erroneous received ideas.

How to choose the stiffness of a tennis racquet

The more a tennis racquet is stiff, the more it provides power, the less it provides control.

Converseley, the more a tennis racquet is flexible, the more the ball stays in contact with the strings at impact, which gives more control.

Beginners : choose a racquet a bit stiff (value 67 Rahmen or higher), it'll provide easy power but still comfort,
intermediate/advanced players/big hitters : choose a semi-stiff tennis racquets (62-67 Rahmen), or for even more control a flexible racquet (62 Ra or less),
players suffering from arm pains : choose an average value, 62-67 Rahmen.

Received ideas concerning the stiffness of tennis racquets

It's a frequent mistake, sometimes made by tennis coaches, to believe that the most flexible tennis racquets are the more powerful and that the stiffer tennis racquets are the less powerful.

The explanation given is often that a flexible tennis racquet would find its power because of a spring effect occuring at impact when the racquet deforms and gets back to its original position.

This explanation is false and it has been scientifically proven : when the racqet deforms, the frame absorbs the enegy of the ball and this energy does not go back to the ball.

At impact, when the ball hits the strings, these things happen :

the strings are deformed by the incoming ball,
the frame is deformed by the incoming ball,
the strings returns the ball (faster than the frame)
the frame gets back to its original position, but the ball is already gone, sent by the strings.

So there can not be a spring effect of the frame because the ball has already left the stringbed when the frame comes back.

Tennis racquets stiffness and comfort

Finding a racquet arm friendly is something rather subjective.

Some players will find comfortable a stiff tennis racquet and will find very hard to play with a flexible tennis racquet.

Some others will prefer more flexible tennis racquets, to have the feeling the ball stays longer in contact with the strings.

Concerning the risks of injury, things are not clear when referring to scientific studies.

We often hear that stiff tennis racquets may be harmful for the arm because they don't deform much at impact and because they don't absorb well the vibrations and the energy, leaving the jog to the arm of the player.

In my experience, I see many players using stiff racquets (more than 70 Ra) without experiencing any problems.

If you suffer from arm pains, I recommand that don't don't take big risks and that you choose an average stiffness for your racquet, between 62 and 67.