TWU String Performance Database - Changing Values?

SpinToWin

Talk Tennis Guru
Hey TW,

Recently I checked the string performance database in order to compare some strings and I noticed what seem to be changes in the values of tension loss... For example I am sure that I remember Head Hawk to have fairly good tension maintenance for a poly, losing something like 16lbs of tension all in all, but the new values are higher. Also, I remember Tourna Black Zone to have had a higher tension loss... Did you redo the tests and change the values or did something get jumbled up after website maintenance (or am I just remembering things very wrongly, which also is likely)?

As always thanks for all you do! I'll go back to mourning Federer's loss now....

Kind regards :)
 

TW Professor

Administrator
Hey TW,

Recently I checked the string performance database in order to compare some strings and I noticed what seem to be changes in the values of tension loss... For example I am sure that I remember Head Hawk to have fairly good tension maintenance for a poly, losing something like 16lbs of tension all in all, but the new values are higher. Also, I remember Tourna Black Zone to have had a higher tension loss... Did you redo the tests and change the values or did something get jumbled up after website maintenance (or am I just remembering things very wrongly, which also is likely)?

As always thanks for all you do! I'll go back to mourning Federer's loss now....

Kind regards :)
We haven't retested or changed any of the strings and I see no evidence of a programming snafu. However, I just did a search for tension loss for these two strings, filtering by poly only and medium tension and fast swing speed. The Hawk was around 16.8 lb loss, as you remembered it, but the Black Zone is at 15 lb loss. That puts both in the top 30 polys for tension maintenance.

Perhaps you mishit the filter choices and chose different swing speeds or reference tensions. That would change your results. (Ha, I just checked mine to make sure I didn't do that.)
 

junbun

New User
FYI, string data does sometimes change depending on how you filter your searches.

For example with head velocity 17 if you search only the string you will get 0 values for stretch @ 40 , 51, 62 lbs
Do the search again with all strings and you get some numbers that don't make much sense (stretch @51 higher than @62)
Do change the sorting criteria and the numbers change again.

I've found at least 4 different stretch % numbers

Yonex Poly Tour Air has 0's or the stretch % descending (higher at 40 than 62)
I've only paid attention to this and a few particular strings, and am not sure how pervasive this issue is or if other measurements also experience this.

So far my guess is the strings that have only 1 impact and 1 tension test have a higher likely hood of these values missing or looking random.
 
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