Serve toss question....

[gzhpcu]

Stand on the baseline and visualize the space above the net through which a successful serve would pass. That window is about 18" high (for a fast topspin/slice serve) and at least 108" wide, according to Mclennan. Here it is argued that the more you hit across the ball, the larger your margin of error becomes (apart from the spin factor),because you are hitting across the window.

The book I mentioned from Brody, Cross and Lindsey, has a full chapter on the angular acceptance. This refers to the minimum angle the ball most have as it leaves the racket just to clear the net and enter the service field. Factors are ball speed, impact height, topspin, higher ball toss, location on court, racket parameters. (chapter 19)

A quote in respect to location:

The closer the server is to the net, the larger the acceptance window...what the server can (and should) do is to toss the ball well into the court so that contact is made when the ball is a foot or more inside the baseline. This has many direct advantages. It will increase the number of serves that go in by increasing the window opening. It will allow the player to get to the net quicker for the serve and volley. It will allow ayou to hit a serve slightly wider, pulling your opponent off the court. It will give the opponent less time to react to the ball.

A recent article in Tennis Magazine (pg 45, February 1994) noted that Pete Sampras strikes the ball when it is two feet inside the baseline.

[uspta146749877]

I will try to get a book

I will try to get a book-it will take a month,I think.
I cannot comment without seeing a book

[tennis_chiro]

An illustration from Julian

Is it obvious that a MORE FORWARD toss would increase an acceptance
window?
Do you assume that a MORE FORWARD toss will be combined with a higher amount
of topspin?

Julian wanted me to post this image for him. Must confess, I had to go to FAQ to figure out how it is done. Really quite instructive.

Here it is

[img]servetrajectory.pdf[/img]

I'm curious if this will work.

This illustration is just the simplest geometrical representation of the problem. No allowance for gravity or spin.

don
Well, that doesn't work, but the attachment is there. How do I get it right in the text?

[tennis_chiro]

OK, I think I got it now.

Let's try this

[ATTACH]servetrajectory.pdf[/ATTACH]

No, that didn't work either.

Phil, how do I do this?
don

[uspta146749877]

A partial success-thank you

1.It should work for all NON-uspta accounts-from your E-mail it looks like it does NOT
2.I had this problem sometime ago

[gzhpcu]

Let's try this

[ATTACH]servetrajectory.pdf[/ATTACH]

No, that didn't work either.

Phil, how do I do this?
don

Here you go:



Uploaded with ImageShack.us

pdf files can not be displayed. You need to capture the image and convert it, to say, jpeg format. Then upload it on a host, say imageshack, from which you can the publish it.

Merry Christmas guys...

[gzhpcu]

The graphic in the previous post is for a theoretical, fast completely flat serve.

In reality



Uploaded with ImageShack.us
(Figure is from Plagenhoef)

The amount of ball drop during the flight from racket to court depends on gravity, ball spin, ball velocity, height of impact, angle of departure and wind conditions.

[uspta146749877]

Plagenhof

The graphic in the previous post is for a theoretical, fast completely flat serve.

In reality



Uploaded with ImageShack.us
(Figure is from Plagenhoef)

The amount of ball drop during the flight from racket to court depends on gravity, ball spin, ball velocity, height of impact, angle of departure and wind conditions.

Does Plagenhof has any kind of picture about a first part of s serve-
i.e on a left hand side part of a court?

[gzhpcu]

Here is another figure from his book...

By gzhpcu at 2009-03-20

[gzhpcu]

Yet another one:


Uploaded with ImageShack.us

Remember, jumping was not allowed back then...

Sorry for the quality, but I did it in a hurry: shot the picture on my iPhone, sent it to Google Documents, captured the screen to transform it to jpeg format, then uploaded in Imageshack.

[gzhpcu]

Really recommend Plagenhoef's "Fundamentals of Tennis", a classic, even though written in 1970.

[tennis_chiro]

How I spent Xmas Eve

Really recommend Plagenhoef's "Fundamentals of Tennis", a classic, even though written in 1970.

Well, Merry Xmas everyone. what are you doing here?

Clearly, I have to ask Santa for Plagenhoef's and Brody's books. But I tried to do a little tinkering on my own yesterday. I made a mistake and did a Quark document for the web instead of for print. I'll have to redo it to get it to a jpeg, but it's attached anyway. Also we'll see if the Photoshop jpeg of the spreadsheet pdf shows up right here. You'll have to open the attachment to play with the different inputs (height, clearance, final and initial speeds...final is at court contact). And these serves are right at the T from close to the centermark. No allowance is made for that additional distance, which I guess Brody made a big point of in recommending standing away from the centermark.

My first question is did Plagenhoef account for the slow down in the ball. And the fact that it is a lot slower in the last 21 feet past the net, or did he just ascribe the 102 mph average to account for that, or does it matter? I also suspect the loss of absolute velocity is a lot greater proportionally from strike to net than from net to ground, because of the wind resistance increased with the square of the velocity of the ball. Does it matter?

And it appears to make a really big difference to reach up 6" more! I think today's average male server is contacting the ball more than 10' off the ground, at least quite a bit more than 9' until you account for reaching into the court 4 feet, but with a slope of less than 2" per foot, that should cancel out on net clearance. Although I want to change my spread sheet to allow for that and see what we get.

So here goes

[ATTACH]TimeToNetJPG.jpg[/ATTACH]

I couldn't get the spread sheet loaded as a spread sheet. Anyone who wants it can send me a private message with your e-mail and I'll send you the actual spreadsheet and you can plug in your own numbers. Also, the attachments are grey scale because the attachments got too big in color.

Merry Christmas,
don

[tennis_chiro]

Try that once more

Still doesn't work, but if you hit the zoom out (command - on the MAC) button, about 6 times, you can see it.
Evidently, I need the remedial 21st century computer class.

Here:

[jpg]TimeToNetJPG.jpg[/jpg]

[tennis_chiro]

Here's my illustration

Remember you have to zoom way out. It may be easier to look at the attachment separately. Here

[jpg]DonsIllustrationJPG.jpg[/jpg]

[tennis_chiro]

It may be easier to look at the pdf

Attached is the pdf. It wouldn't work when I had it in the last post.
I hope all this sparks a little discussion.
don