Polyester string tension and arm Issues

jhick

Hall of Fame
So help me understand the science behind this. It is recommended not to string poly at higher tensions because it can be hard on your arm (TE, shoulder, wrist, etc.). So string it at lower tensions, easy fix as long as the increased power is controllable. That makes sense to me. But conversely, I typically read that typically because of the high tension loss, poly will "go dead" and that is also bad for your arm. So many suggest cutting the strings after hitting with them for a specified number of hours. But isn't the tension loss (lower tension) a good thing for your arm? Or are they just two unrelated issues?

Thanks.
 

Dartagnan64

G.O.A.T.
Tension loss is not the problem with poly. Loss of resilience is the problem with poly. All strings lose tension after stringing. Poly loses all its give and shock absorbing potential (what little it had). Nylon and gut are far more resilient and therefore remain arm friendly even as tension goes down from stretching the material.
 

tennis007

New User
So help me understand the science behind this. It is recommended not to string poly at higher tensions because it can be hard on your arm (TE, shoulder, wrist, etc.). So string it at lower tensions, easy fix as long as the increased power is controllable. That makes sense to me. But conversely, I typically read that typically because of the high tension loss, poly will "go dead" and that is also bad for your arm. So many suggest cutting the strings after hitting with them for a specified number of hours. But isn't the tension loss (lower tension) a good thing for your arm? Or are they just two unrelated issues?

Thanks.
I agree with Dartagman64 and would like to add a few minor points. Poly string after certain hours of play become "dead" and in some cases stiff, in result can cause issues to your arm, wrist, shoulder, etc.. Tension loss in gut/synthetic gut/multifilament strings, will not cause issues with your arm, since they become softer. Some poly's will become softer after certain time of play Eventually poly string will die and will no longer snap back to it's original place on the string-bed. At this point in time the string will have a dead feel and lower power. It will loose it's liveliness and spring. It is best not to wait for poly to break, unless you are a big hitter and break a poly string prior to it's end of life span.
 
It's a great question, but at the same time it is losing tension it is also losing its ability to stretch. Then at a certain point the stretch is all gone and no matter how much tension it loses, you are still hitting that dead stop.

You can also talk about the string bed locking and being harsher as the strings can't slide around as freely as they did before.

Another problem is that a lot of people leave it in for 6 months when it was not meant for that.
 

Dartagnan64

G.O.A.T.
There is a reason they put crumple zones in motor vehicles. Polyester is like driving a 1950's car without crumple zones. The energy of a collision is going to be transmitted straight to the occupants. Much rather be in the 2021 Range Rover in a collision than 1956 Rambler.
 
think of it this way. You have molecules packed together making a string. When you hit the ball, the strings stretch, causing the molecules to get more in line as they are stretched out. When hit really hard, just before they break, they line up in single file (in certain areas of the string). When they go dead, the molecules are starting to get inline (a little stretched) and staying there. So, the string is a little soft feeling, but already half way to being fully stretched (even at rest). Then, you hit the ball, the string lengthens a little, but the molecules are already inline and can't stretch any more. 2 options--1) the string breaks 2) the string stops stretching abruptly, doesn't break, but send all that shock and vibration up through your racket and arm.
 

jim e

Legend
@Steve Huff
I understand all above, but why do posters here comment that they pre stretch poly strings? As would that not decrease the life of the string?
I have yet to pre stretch a poly.
Seems pre stretch a poly would make string go dead faster.
 

zipplock

Hall of Fame
@Steve Huff
I understand all above, but why do posters here comment that they pre stretch poly strings? As would that not decrease the life of the string?
I have yet to pre stretch a poly.
Seems pre stretch a poly would make string go dead faster.
Pre stretching a poly will do two things:
1. Decrease the tension loss after stringing
2. Decrease the time before they go dead

Advantage is that strings are predictable for X amount of time
Disadvantage is that they should be replaced for often
 

Dartagnan64

G.O.A.T.
@Steve Huff
I understand all above, but why do posters here comment that they pre stretch poly strings? As would that not decrease the life of the string?
I have yet to pre stretch a poly.
Seems pre stretch a poly would make string go dead faster.
These people are able to play with non-resilient strings and so make them even less resilient suits their purpose of playability and longevity. Buyer beware however. Not every elbow can tolerate this.

I can't go near Kirschbaum strings for that reason. Even the 18g stuff feels like titanium wire to me.
 

socallefty

Hall of Fame
Poly going dead and poly losing tension are not the same thing - it seems like a large number of people on this forum seem to conflate the two completely different physical phenomena. Poly going dead relates to poly losing its resilience quickly compared to other strings - especially with the stiffer polys this happens really fast within 5-10 hours. You feel a big difference in feel from freshly strung poly once it goes dead and you feel the harshness and discomfort in your arm.

Poly like other strings also loses tension and you lose control while it gets erratic over time - in many cases, it takes longer for the tension to be appreciably different where you notice the erratic control than it takes for poly to go dead.

My advice would be to restring as soon as you feel the poly is getting harsh and not wait till the control gets erratic especially if you are an older player with aging tendons.
 

esgee48

G.O.A.T.
I am not going to counter any of the opinions here. Consider this; you can stretch metal cable or metal wire if the applied tension is great enough. The metal is flowing in a plastic manner since the deformation is permanent. Now consider a polyester string like 4G. Its structure is amorphous or semi-crystaline. It would be considered to be less amorphous than ALU. ALU stretches more than 4G with each impact of the ball. In 2-4 hours, the ALU feels dead to the player because it has lost tension due to all the ball impacts. 4G may start off feeling muted because it does not stretch as much with each ball impact. Its structure makes it more able to resist stretching in a limited manner. So it may last 12-16 hours before feeling totally dead to the player. At this point, whether it is ALU or 4G, you can still make the string stretch if you can hit the ball hard enough. It's just that very few players can generate the RHS required to do so. Having said this, if your strokes can stretch 4G for 12 hours, and then you break the string, why wouldn't you use it? I have had clients that liked the feel of ALU for 2 hours, but hated it after that because the spin and control went away. With 4G, they can play with it until they break it.
 

USPTARF97

Hall of Fame
String it as low as you possibly can and still control the ball. Replace every 5-6hrs. This has as much to do with getting the maximum playability from the string as it does preserving the arm. As soon as it notches and requires straightening it’s done.
Pre-stretching poly for me and many players just makes it play stiffer and detracts from several attributes that make poly one of the primary choices among players. If one is having to pre-stretch poly to control the ball and going up 2-3lbs doesn’t help, the issue is not the string.
Will leave all scientific explanations to the scientists. We just play tennis.
 
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gzafra

New User
AFAIK poly loses tension quickly in the beginning then steadily. By pre-stretching you'd skip the first part and go straight into the second. Some polys feel very different after 1-2 hours of use so I guess it makes sense for pro-players to have a consistent feel of the string during their play.
 

USPTARF97

Hall of Fame
AFAIK poly loses tension quickly in the beginning then steadily. By pre-stretching you'd skip the first part and go straight into the second. Some polys feel very different after 1-2 hours of use so I guess it makes sense for pro-players to have a consistent feel of the string during their play.
That is why they start with fresh string and switch frames either every ball change or every set. That being said for the most part they practice with their frames just like we do and put several hours on the string bed and in many cases play until they break. For me I always start a match with fresh string and know exactly how it will perform for a couple of hours. The playability the first couple of hours of full poly is the best for me regardless of the brand of poly it is. Leagues and tournaments are basically tie breaker in leu of the third set so a fresh frame will normally work for the entire match. If not have a few frames in the bag.
 
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