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Mazilla2219
12-03-2009, 05:49 AM
Are string elasticity and string stiffness the same or do they correlate together?

I ask because it looks like the consensus is that a specific overall string bed stiffness is what players/stringers are thriving for when they initially string a racquet. With this in mind, doesn't string elasticity play more of a role in how the string bed flexes during impact? If this is the case, why not omit string bed stiffness and just measure string elasticity, or can it even be measured.

jazzyfunkybluesy
12-03-2009, 06:10 AM
A user on the board named Technatic can tell you how to do an elasticity test. It can be measured but the playibility of the string is paramount.

raygo
12-03-2009, 02:53 PM
Good post, OP. :)

Have you checked the USRSA string selector guide (2008 was the most recent data, I believe)? I found this site invaluable in learning about strings.

http://www.racquetsportsindustry.com/issues/200809/200809allstrings.html

The chart lists almost every string available along with their stiffness rating and tension loss.

The two terms are interrelated, elastic strings have low stiffness and vice versa. For example, natural gut is the most elastic string around, so it will have the lowest stiffness rating. Of course, strings of the same stiffness/elasticity will vary when comparing different materials or constructions.

The more I played the game, the more I realized you can't always trust your perceptions as a player (like players seeing themselves on video for the first time). For me, having the lab data to fall back on makes things a lot simpler. Lots of people criticize the science behind tennis, and some even say it's flat out wrong, though.

SW Stringer
12-04-2009, 12:31 AM
Are string elasticity and string stiffness the same or do they correlate together?

I ask because it looks like the consensus is that a specific overall string bed stiffness is what players/stringers are thriving for when they initially string a racquet. With this in mind, doesn't string elasticity play more of a role in how the string bed flexes during impact? If this is the case, why not omit string bed stiffness and just measure string elasticity, or can it even be measured.

String Bed Stiffness is a static measurement of the finished product, a way to ensure the quality of the finished string job. The stringer wants to duplicate the "feeling" of the string bed every time he does the same setup (string, racquet, tension) and measuring and recording the SBS with any of the available devices is a very important step in maintaining a quality product.

The string stiffness and elasticity measurement done in the lab on a piece of string by the USRSA is a dynamic test (string hit with a hammer and the subsequent deflection and tension change recorded by a computer) that simulates a 120 mph serve. This laboratory dynamic test is a way of simulating the 5 or 6 milliseconds that the string bed interacts with a tennis ball. The chart of stiffness measurements then lets you see all the different strings with similar characteristics so that you're not doing a "blind search" for the perfect string.

Valjean
12-04-2009, 03:15 AM
....Lots of people criticize the science behind tennis, and some even say it's flat out wrong, though.
This deserves to be aired separately, though, with its own topic. Much of the "criticism" is for reliance on science as that, and doesn't have a leg to stand on, or show much familiarity with the lab work, its method and so on. Instead of its improvement, they merely prefer it go away. Often it's not been too sincere, as well, having been designed to get at individuals instead, typecast them, etc.

Valjean
12-04-2009, 03:22 AM
Are string elasticity and string stiffness the same or do they correlate together....
Years ago, the USRSA offered us a table of strings showing how much a pre-selected length of string extended when stretched with a, I believe it was, 60-lb. weight. It would be potentially insightful if that effort were somehow redesigned and perhaps duplicated here and now, too, and a result supplied with each stiffness measurement.

raygo
12-04-2009, 04:30 AM
This deserves to be aired separately, though, with its own topic. Much of the "criticism" is for reliance on science as that, and doesn't have a leg to stand on, or show much familiarity with the lab work, its method and so on. Instead of its improvement, they merely prefer it go away. Often it's not been too sincere, as well, having been designed to get at individuals instead, typecast them, etc.

Good point, Valjean. I was really defending the general principles discussed at USRSA and in the Physics of Tennis books. It's mostly posters misinterpreting it or going overboard that might give other readers the impression that it's all hooey. The published stuff, at least as far as I've read, is pretty valid and worthwhile reading. People can play just fine without it, but I don't think anyone got WORSE for learning it, either (unless they spent more time studying than practicing). The getting at individuals thing is aggravating and creeps into virtually every potentially meaningful discussion around here--that's the Internet for ya.