Roger Federer Serve Locations: Deuce Court

[John Yandell]

Would love to get your thoughts on my latest article, "Roger Federer Serve Locations: Deuce Court"

[gzhpcu]

Great article John. Thanks to high speed photography, myths like "carving around the ball" for a slice serve have been debunked. Even great players like Pat Rafter, in his recent series on the serve, refers to this erroneous image.

So it appears that the parameters on the type of serve and the direction are minimal:

- all serves have pronation and upper arm rotation

- the racket forms an angle to the hitting arm

- all serves have the face of the racket facing towards the body prior to the hit and facing away from the body after the hit

- 2-3 milliseconds contact determines everything

At contact the determining factors for the type of serve and direction are:

- height of contact with the ball relative to the player(the lower it is, the larger the angle between racket and arm)

- position of impact relative to the player's head

- inclination of the racket head at impact

- contact point postion in respect to the edge of the player's body

- speed of the racket at impact

Am I missing anything here? Regards, Phil



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[John Yandell]

You covered as well as I did. In the other serve series I will be giving some ideas about how th make it actually happen...

[klacr]

Interesting stuff. It's all in the details.

The difference some player's describe in the kinestethic feel and what's actually happening has always intrigued me. A very fine line between hitting out wide and hitting down the T. Not a huge gap or obvious adjustment like you see at a lower levels. You practically know the serve your opponent hits before they do due to their exaggerated wind up and toss.

Here are some questions: When we talk about a matter of just a few degrees that the racquet face can turn to create the difference an out wide serve and down the T, does anyone know exactly how many feet of difference that just 1 degree can make on any shot? Is merely 1 degree of change universal on how much distance you get or can 1 degree vary based on racquet head speed and approach to the ball? In other words, if I first hit the ball with my racquet face one way, then I was able to change my racquet face just 1 degree, how many feet would I be away from my initial hit?
Hope that made sense. Thanks

Kyle LaCroix USPTA
Boca Raton

[John Yandell]

Yeah good question. Any geometry students out there that actually know the answer?

[GeoffWilliams]

The degree would have to be either one degree of the ball's surface, or one degree of the racquets surface, either way, one degree would be minimal.

[klacr]

Thank for the answer Geoff. Figured 1 mere degree would have minimal effect but you'd probably need upwards of 5 or 10 degrees to really notice anything. Would that be correct? Always curious as to how many degrees a racquet face would need to change for noticable difference. Inquiring mind. Not a geometry student

Kyle LaCroix USPTA
Boca Raton

[tennis_chiro]

Corner to Corner: less than 13 degrees

Thank for the answer Geoff. Figured 1 mere degree would have minimal effect but you'd probably need upwards of 5 or 10 degrees to really notice anything. Would that be correct? Always curious as to how many degrees a racquet face would need to change for noticable difference. Inquiring mind. Not a geometry student

Kyle LaCroix USPTA
Boca Raton

Geoff makes a key point in that it's both the angle of the racket and the point on the ball where the racket meets the ball, but the simple geometry is that it is about 13 degrees from corner to corner of the 13.5' wide service box at 60' from the center service mark to the T. And to a wide serve that hits about a foot to 2 feet down the sideline from the corner of the box is probably a full 15 degrees from the serve on the T.

Here's the math

Tan = Opposite/Adjacent. Therefore:Opposite = Adjacent * Tan (R in radians in Excel)

Take the distance down the center service line as an approximation. We know that is at least 60'.

Adjacent(ft)-D
Angle(degrees)-A
Radians=A*PI/180=R
Tan ( R )
Opposite(ft)=D*Tan(R)

D--------A----------R------------------Tan of R----------Opposite
60.00---1.00----0.017453293----0.017455065-------1.05
60.00---2.00----0.034906585----0.034920769-------2.10
60.00---5.00----0.087266463----0.087488664-------5.25
60.00--10.00---0.174532925-----0.176326981------10.58
60.00--15.00---0.261799388-----0.267949192------16.08
60.00--13.00---0.226892803-----0.230868191------13.85

And what a pain trying to format stuff here. Someone tell me how to do this.

don

[klacr]

Don,

wow! I'm so glad you are good at this number crunching. Not my specialty by any means. This was very helpful. Good to know smart people.

Kyle LaCroix USPTA
Boca Raton

[gzhpcu]

BTW, I forgot another parameter: (Geoff will like this...):

The impact point on the face of the racket:
(higher up for the flat serve?)

Stringing tension

Type of strings

[tennis_chiro]

BTW, I forgot another parameter: (Geoff will like this...):

The impact point on the face of the racket:
(higher up for the flat serve?)

Stringing tension

Type of strings

You may be right...no, you are right, Phil, but keep this up and you are talking about non-linear solutions of multiple partial differential equations or the thesis topic for someone doing their PhD in Biomechanics. Way beyond the scope of anything we are going to solve here!

But it is nice to recognize it helps to reach up, the contact point on the face effects the amount of deflexion of the strings as well as the frame and lesser tension is going to create a greater influence on the outcome or at least a more variable one. (We'll let Geoff confirm that or not.)

don

[John Yandell]

13 to 15 degrees seems about right when you look at the racket face animation in the article.

[gzhpcu]

And to think that the great Pancho Gonzales, never had a tennis lesson, never analyzed anything, and his beautiful movement just came naturally. Aah, the good old days...

Just goes to show how great our bodies are. Doing a lot automatically. You just need the Gonzales or Federer DNA (might be possible some day... ). Think of all of these parameters and you will never hit a serve in the serve box.

Just simplify and use John's tips on the serve he wrote in his recent series.

[GeoffWilliams]

I was self taught also, and it has been a battle just reaching 4.5. Nothing comes naturally in this game nowadays.

[richberman]

Right ON!

John,
Great article and 100% correct. I am so pleased you debunked two of the most common misconceptions about placement. Hurray!!
Thanks, rich