Tennis Tip: “Tighter strings for more control and less power; looser strings for more power and less control.”
By Brian Cheney, USPTA
You may have heard about string tension versus power and control. Yes, players will tighten their string tension when playing at higher altitudes or higher temperatures to help control the ball more. Or other players reducing string tension to try and increase their power. Court surface may also dictate change in tension, like on a clay court that reduces ball speed after the bounce, a player will want more power. I remember in college having a racket strung too loosely and I felt as though I couldn’t keep the ball in the court. I just came across an interesting study on this subject in the book Technical Tennis, by Rod Cross and Crawford Lindsey.
Here we go. The experiments with string tension definitely reveal the ball coming off looser strings has more power. But it is much less than we think. I was amazed to read on a 60 mph hit ball, if the string tension is loosened by 10 lbs, the resultant increase in ball speed is less than 2%, or 1.2 mph! So a player should be able to adjust readily to this slight increase in speed—which causes the ball to travel several inches more. So then why does it feel so much more out of control with looser strings?
Here is where the technical answer helps. Besides increased ball speed, two other changes to flight path happen. One is that with looser strings the ball is on the racket a slightly (1 millisecond is my guess) longer time, so with a low to high swing pattern, the ball leaves the racket with a slightly higher trajectory than tighter strings. A second and more complex effect is when the ball plows into a loose string bed, the ball digs a hole into the string bed and pushes the long strings down. This creates a small bump or hill in the strings at the lower part of the ball. The hill causes the rebound angle off the strings to be higher than with tighter strings. A one degree increase in angle will make the ball travel 4 to 5 feet farther. That is the most significant effect of loosening the strings. When you are used to a ball landing two the four feet inside the baseline, and then it goes two to four feet out, you feel like wow, I’m losing control! The authors of the book conclude the old adage might need to be revised to “string loose for depth and tight for safety.”