# Do Poly Strings really lose Tension Faster

Discussion in 'Strings' started by kenshireen, Mar 4, 2013.

1. ### kenshireenProfessional

Joined:
Aug 25, 2004
Messages:
1,065
I string for a group of guys.
One of them insists poly holds tension better than syn since they don't move.
I told him movement has nothing to do with tension in poly.
He asks...well when syn gut loses tension it moves... why shouldn't the same be for poly.

I don't have an answer to the last question... Why don't the strings move... is it the nature of the material.

2. ### cornersLegend

Joined:
Jul 31, 2008
Messages:
5,448
Yes, it's the nature of the material. Copoly strings, by design, are slippery. Saying that they don't move is an oxymoron. They actually move more than syngut. They slide with the ball during impact and then snapback to their original position as the ball bounces off the strings. This happens in 4 milliseconds, so by the time the player looks down at the strings they long ago returned to position. Syngut strings, having softer and more deformable surfaces with more interstring friction, move with the ball but then often get stuck out of line. So poly strings move twice as much as syngut strings, creating the illusion that they "don't move." Show your friends this article and video: http://www.theatlantic.com/magazine/archive/2011/01/the-new-physics-of-tennis/308339/

3. ### McLovinHall of Fame

Joined:
Jun 2, 2007
Messages:
3,387
Because string movement has nothing to do with string tension. It has everything to do with string friction.

If you look at slow motion videos, you will see poly strings moving, but because there is low coefficient of friction, the strings will 'snap back' to their original position.

Synthetics generally have a higher coefficient of friction than polys (see http://twu.tennis-warehouse.com/learning_center/COFreporter.php ), thereby preventing them from 'snapping back'.

4. ### McLovinHall of Fame

Joined:
Jun 2, 2007
Messages:
3,387
While I was searching for the TWU link, corners beat me to it...

5. ### RabbitG.O.A.T.

Joined:
Feb 11, 2004
Messages:
12,749
Location:
at the bottom of every hill I come to
To their credit though syn gut does lose tension PDQ. from a playability standpoint, you can feel syn gut's lack of performance more IMO than poly. With syn gut you start missing, with poly, you start missing and hurting!

6. ### JT_2eightyHall of Fame

Joined:
Mar 11, 2009
Messages:
2,521
Location:
clearing out my collection
One way to show your friends the real-world evidence is to have them take a racquet with Fresh Strung Poly: pull one of the main strings to the side and release; watch how quickly it snaps back into place.

Take that same racquet after 5-10 hours of hitting, and do the same 'snap back test' as above. The strings still slide back, but you can notice the snap back is not quite as quick as when fresh, nor do they go back completely in some cases (the 'quick snap back' becomes a 'gradual return').

Another reason people anecdotally don't notice the loss of tension is because old poly strings actually become *Less elastic* over time; they get stiffer but also tension loss is occurring. Sometimes the tension and elasticity loss cancel each other out in terms of feel, but at a certain point either the tension loss dominates (i.e. loss of control) or the elasticity loss dominates (i.e. loss of comfort).

Some people are more acute to noticing the changes, and some don't mind playing with dead poly. People with sensitive arms or aging joints will notice the loss of elasticity right away, while people at high levels of play notice the loss of control after a short duration. Most rec players don't notice either the elasticity or tension loss, and just adapt to the changing stringbed every time out. Whether thats a good or bad thing is a judgment call that depends on the player, but for some that results in injury from playing with really dead poly for months and months.

Last edited: Mar 4, 2013
7. ### tennis_pr0Semi-Pro

Joined:
Aug 4, 2009
Messages:
562
I restring my racquets about every 5 hours. I play with all black widow, which is a poly that loses tension a bit faster than most poly's because of how soft it is. I can get 10 hours out of it, but I do notice a difference in control after about the 4 or 5 hour mark. If I'm just hitting, I will keep them in longer, but for a match, I won't go over that 5 hour mark.

8. ### ricardoProfessional

Joined:
May 12, 2009
Messages:
937
Why don't the strings move... is it the nature of the material?

Why don't the strings move... is it the nature of the material?

All strings move, but not all strings snaps back.

Poly strings move the most but they snap back the best, that is why they look as if they haven't moved at all.

Others strings move, but they don't snap back. They get stuck where they move.

Poly loses tension the most and the fastest compared to other string materials.

http://twu.tennis-warehouse.com/learning_center/reporter.php

9. ### hcelizondoNew User

Joined:
Sep 25, 2008
Messages:
93
Location:
Mexico
Get an ERT and measure it by yourself...

10. ### Bobby JrLegend

Joined:
Jul 5, 2010
Messages:
7,768
Your friend is wrong - and obviously hasn't thought it through.

Here's a simple way to disprove his notion.

> Take a thin piece of wire and a rubber band.

> String them around something so they hold tight.

> Push them in the middle ten times.

Now, which one still holds perfectly straight? The stretchy rubber band or the piece of wire? Or course the rubber band does - because it's got more elasticity. Ergo, it holds its tension longer.

11. ### thebeast73Rookie

Joined:
Aug 14, 2010
Messages:
156
Another good way to prove it would be to string a racket with poly and another with a syn gut or multi. Have the guy hit with both for about 10 or so hours, unless he is likely to break them faster than that, then just go for a shorter duration. Then cut the strings in front of him and have him see how the syn gut seperates, because it is still under considerable tension, and how the dead poly doesn't, because it has lost most of the tension pulling on it.