Interactive Forum August 2012: The Invisible Collision

[stumphges]

In fact they are Flex Infinity strings 1.25 White. You can find out more at www.flexinfinity.com.au. Be sure to check out the additional info about each strings performance by clicking on the pic of string. Very interesting reading - give comparison of dynamic tension (most important), tension loss and energy return. There are graphs also showing comparison.

It looks like Flex Infinity is using the same dynamic stiffness, tension loss and energy return measurement protocols as Crawford Lindsey uses at TW University.

Do you have any data on sliding and static interstring and ball/string friction? Are you measuring surface hardness by any chance?

[fastec]

Yeah it's true if you are hitting a world class high velocity high spin forehand you can close the face a few degrees...goes against the conventional belief. But Rod Cross has formulas that show how much, when etc. Not sure if I'd teach this to the average student, and in the archive the pros are vertical more than they are closed...

[John Yandell]

Actually above was me--fastec is the incredible camera we are using--was testing their company login...but the comment stands...

[jimlosaltos]

thx

Do you mean Cross?

Yup.

[jimlosaltos]

On TV

4 milliseconds on the contact and no the ball is not sliding nearly that much in my view--look at the pocketing on the side view--the strings are sliding--this is the snap back effect...

On the Apple thing Firefox will solves the problem.

In case you missed it, John, this video got mentioned at Cinci I think it was by Fowler, described briefly and said "From Jon Yandell". but not tp.net.

[jimlosaltos]

Suggestion: Serve Kick and Slice

Reinforcing my reputation as a greedy customer <g>. I'd love to see two, similar videos comparing serves hit with kick and with slice.

Had a long, great discussion with one of your contributors on this forum about how the action of the strings is different during some strokes, such as the serve, because they have to move diagonally. In a sense, this video simplifies the issue because the mains slide straight down on the "rails".

Cross and Lindsey wrote about balls sliding 4 inches on some serves (please correct me if my vague recollection is wrong). (Or the strings move but not the ball, it's all relative.)

As your contributor (sorry, I forget his name) noted: Fed only straightens his strings after hitting his inside-out forehand, which imparts sidespin.

Just an idea. Thanks for the great content.

[John Yandell]

We did some 4000 frame filming in Cincy--not as successful without the controlled conditions. But we'll see what we get.

[richberman]

co-poly

John,
How do you do it? Just when I think I have a decent grasp of this game
your tutelage demonstrates I have lots to learn.
Thanks,
rich

[John Yandell]

Thanks Rich. The game keeps changing and our ability to understand it changes and hopefully we will all keep learning!

[carlpro]

It would be nice to have a side by side comparison with different strings. What actually is the difference in string reaction?

[John Yandell]

Well non poly doesn't slide like that. The differences among poly strings? There are people working on that--how much spin etc? We will be following that research.

[tntenniswhiz]

This website physically affects me....

I read some of these articles, view some of these videos, read some of the comments....and I just get giddy!!!!

[John Yandell]

Now that is one of my favorite posts so far.