We have been testing strings for power potential since 1984!  Currently, we have over 500 strings registered on our website, and we will put a link in this post that will take you there.   Over the years, we have tested that several times that number but need to remove some strings that simply do not need to be in this data while keeping “legacy” strings for reference to today’s offerings.

What does the power potential of string have to do with String Bed stiffness?  While a single strand of string tells us a lot about the performance characteristics of any string, it is the total string bed that you play with, not a single string!

We test for String Bed Stiffness in four (4) different ways: Babolat RDC, Flex Four, Master Tensometer, and our proprietary String Bed Master.

What we want to clarify is the power of the string bed stiffness, and to do that, we need to include the tennis ball, which is, by design, not very efficient. I believe the rebound percentage is about 53 to 58 percent. If the rebound percentage were closer to 100 percent, the ball would not stay in the court!

The graph below helps us understand what String Bed Stiffness will work in any given player situation.

Power vs String Bed Stiffness

I know there are a lot of lines, but I am certain you can understand them. We will help you along and explain why this is very important to you and us!

The vertical axis (Y) is Power, and the horizontal axis (X) is String Bed stiffness in pounds per inch. Every device we use for string bed stiffness presents the force in pounds per inch.  The green dotted box represents the “normal” range (≈ 160. to 210.0) for string bed stiffness.

If we want to maximize the power of the ball contact and string, we would need a string bed stiffness of about 100 pounds per inch, which is achievable but not “normal.

The upper curve (brown or red) represents the sting bed only.  So you see a power range of 20.0 down to 6.67.  The lower curve (blue) introduces the ball and, due to the ball design, does not add any power but detracts from power.  So you see a power range of 13.7 down to 8.38.  Because we don’t know how hard the ball is being struck, we prefer to use the string bed-only curve.  It is, however, critical for us to know how the ball is participating.

An interesting and important value of the graph is the power value. As the string bed becomes stiffer than the ball (≈ 210.0 pounds per inch range), the ball will provide more power than the string bed. Not much, but at least the ball will not detract from the power!