# What is the best way to estimate service speed?

#### solarflair

##### New User
Hello all--

I'm looking to work on my second serve, and I read that two-thirds of the speed of the first serve is a good speed for your second serve, but I've never measured them before. My first serve is flat and hits the fence around waist-high in one bounce (I'm 5 foot 7 as of now), but my second (slice) usually takes 2 to 4 to reach the fence. I definitely feel that I'm swinging too slow and like I'm trying to just get it over the net. I want to set the goal of having it be two-thirds the speed of my first serve, but I don't know what that would look like with a slice serve because the spin is different than the flat. Is there a good way to estimate the speed of both of my serves so that I can figure out how much more speed my second needs?

Thanks

#### LeeD

##### Bionic Poster
Look at other players if your level.
Say...4.0. Most hit 1st serves 80-90.
If your serve is faster, and scares them, you might hit 100.
2nd, swing as fast or faster, add spin, and should hit back wall by 2nd bounce every time....70 mph

#### SystemicAnomaly

##### Talk Tennis Guru
Your 2nd serve swing speed should be just as fast, IF not faster, than your 1st serve speed. Learn to hit a decent topspin-slice rather than a pure slice for 2nd serves. TS-slice should have a better net clearance and arc down into the service box more than a pure slice serve. Pure slice might be a good alternative for your first serve. Eventually, you should be able to develop a kick serve from the TS-slice serve.

If you swinging as fast and are putting enough spin on the TS-slice serve, then the fwd ball speed should about 65% to 70+% of your 1st serve speed. Assuming you are a righty server, you might be brushing across the ball somewhere between from 8 to 2 o'clock to a brush from 9 to 3 o'clock. Instead, try for a bush angle that is 45 degrees or more. You might even consider 7 to 1 o'clock.

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#### SystemicAnomaly

##### Talk Tennis Guru
If you are not doing so already, use a continental (or extreme conti) grip on your 2nd serves. Your first serves should also use a conti or, at the very least, a semi-conti (Aussie) grip.

Develop at TS-slice 2nd serve that you can get into the box at least 17-18 times out of 20. As soon as you are getting close to 90% of those serve in consistently, increase your serve speed and still shoot for 85% or better.

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##### Talk Tennis Guru
Hello all--

I'm looking to work on my second serve, and I read that two-thirds of the speed of the first serve is a good speed for your second serve, but I've never measured them before. My first serve is flat and hits the fence around waist-high in one bounce (I'm 5 foot 7 as of now), but my second (slice) usually takes 2 to 4 to reach the fence. I definitely feel that I'm swinging too slow and like I'm trying to just get it over the net. I want to set the goal of having it be two-thirds the speed of my first serve, but I don't know what that would look like with a slice serve because the spin is different than the flat. Is there a good way to estimate the speed of both of my serves so that I can figure out how much more speed my second needs?

Thanks
The speed of my 2nd serve would be one of the last things I worry about. Way more important for me is placement, spin, depth, and disguise. If you're satisfied with all of these and speed clearly is lacking, then worry about speed.

#### Raul_SJ

##### G.O.A.T.
Another approach that does not require you to measure the speed:

Hit a second serve as fast as you can while still getting 90% in to your target.

That is your second serve speed.

#### solarflair

##### New User
The speed of my 2nd serve would be one of the last things I worry about. Way more important for me is placement, spin, depth, and disguise. If you're satisfied with all of these and speed clearly is lacking, then worry about speed.

My opponents usually put it away haha. It's basically like I'm serving them up a gift. I think I'm worrying the most about speed because they are standing inside the baseline when I serve it.

#### solarflair

##### New User
If you are not doing so already, use a continental (or extreme conti) grip on your 2nd serves. Your first serves should also use a conti or, at the very least, a semi-conti (Aussie) grip.

Develop at TS-slice 2nd serve that you can get into the box at least 17-18 times out of 20. As soon as you are getting close to 90% of those serve in consistently, increase your serve speed and still shoot for 85% or better.

That seems like a good goal to shoot for. I'm using the continental for both. I definitely think a lot of the flaws in my second serve are due to me being too conservative, so aiming for it to hover around 85% would probably lead to some faster serves.

#### solarflair

##### New User
Another approach that does not require you to measure the speed:

Hit a second serve as fast as you can while still getting 90% in to your target.

That is your second serve speed.
And thank you as well--I will work on that.

#### GuyClinch

##### Legend
Video your serve and then count the frames. Or use software that does this.. IMHO some of the software that does this seems to lowball serves compared to frame counting.

Calculating serve speed from frame count in digital video (donthireddy.us)

Guesstimate first serve like 85 - 90 second serve like 55-60.. But frame count at let us know.

#### SystemicAnomaly

##### Talk Tennis Guru
Video your serve and then count the frames. Or use software that does this.. IMHO some of the software that does this seems to lowball serves compared to frame counting.

Calculating serve speed from frame count in digital video (donthireddy.us)

Guesstimate first serve like 85 - 90 second serve like 55-60.. But frame count at let us know.
We didn't answer the Q the way that he asked because we did not really feel it was all that important to know the actual speed of his serves. Still don't.

I believe we've given him enough to consider w/o going thru the trouble of trying to figure out his serve velocities. Time better spent.

#### ZanderGoga

##### Semi-Pro
This is the Internet. If your serve barely reaches the back fence on the second bounce, we call that, “about 120.”

#### solarflair

##### New User
This is the Internet. If your serve barely reaches the back fence on the second bounce, we call that, “about 120.”
i'll let my opponents know i serve 120 before every game

#### socallefty

##### Legend
Your 2nd serve needs to be fast enough with enough spin and location accuracy so that the point is still on neutral after the return and you have a good chance to win 50% of your second serve points. If not, it is too slow. You don’t need to know the actual speed - it is too slow if you are on defense after most returns.

#### GuyClinch

##### Legend
This is the Internet. If your serve barely reaches the back fence on the second bounce, we call that, “about 120.”
LMAO. This forum is the opposite of that. You could alter a video of Fed serving - make it look like you are serving and everyone would claim you are serving 60mph and are a 2.5.

#### GuyClinch

##### Legend
We didn't answer the Q the way that he asked because we did not really feel it was all that important to know the actual speed of his serves. Still don't.

I believe we've given him enough to consider w/o going thru the trouble of trying to figure out his serve velocities. Time better spent.
Yeah but knowing your serve speed is fun - albeit humbling for most of us haha.

#### Chas Tennis

##### G.O.A.T.
The fundamental way to measure velocity is to measure distance traveled in a known time.

Distance Traveled = Velocity X Time

1) Video squarely perpendicular to the ball's trajectory about 3 feet in front of impact. Camera on tripod.
2) Calibrate the distance out with a measuring tape or by videoing a yard/meter stick after the serve and before anything has moved. Or put black tape on a piece of PVC pipe.
3) Know or calibrate the video camera's frame rate by viewing a clock.

Distance - traveled in 1 or more frame times
For a 30 fps camera, the time between frames is 1/30 second per frame. or 0.03333 sec.
Conversion factor 100 MPH = 1760" per second. In one frame time at at 30 fps - 0.033333 sec a 100 MPH ball would move 59".

This method is very reliable and you would completely understand after using it for awhile.

An easier was to estimate the serve speed is to use the average diameter of the ball to calibrate instead of the measuring tape or PVC pipe.

I have posted this here and can answer questions.

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#### Raul_SJ

##### G.O.A.T.
This method is very reliable and you would completely understand after using it for awhile.
The margin of error is just too large at 30 FPS. Something on the order of 6% if we recall correctly. Best to go with at least 60 FPS.

#### Chas Tennis

##### G.O.A.T.
The margin of error is just too large at 30 FPS. Something on the order of 6% if we recall correctly. Best to go with at least 60 FPS.
I don't agree. What is the source of error?

#### Raul_SJ

##### G.O.A.T.
I don't agree. What is the source of error?
Recall posters here counting frames on YouTube and calculating the number of frames between serve contact and ground impact. IIRC, a typical estimate was 82 mph +/- 3 mph... depending on if you were able to exactly identify the frame at contact/impact.

#### curly_2350

##### New User
The ball slows down a lot even by the time it crosses the net. The numbers you see on TV are measured right when it's hit. So you won't get comparable numbers to the pros by calculating the average speed of it in flight. Maybe if you're filming in 120fps with a very well positioned camera to get a good measurement of distance between contact and crossing the net you could do ok.

D

#### Deleted member 780836

##### Guest
The speed of a serve is the speed when the ball just leaves the racket, not when it crosses the net or hits the ground or whatever. Your best bet is to find a club that has a radar gun, don't bother with anything else, it will be way way off.

#### Chas Tennis

##### G.O.A.T.
Recall posters here counting frames on YouTube and calculating the number of frames between serve contact and ground impact. IIRC, a typical estimate was 82 mph +/- 3 mph... depending on if you were able to exactly identify the frame at contact/impact.
How does that apply to my post, #17?

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#### GuyClinch

##### Legend
This would be the best way absolutely true. Frame counting is the cheapest way.. There is also the swing vision app which seems kinda brutal in its low numbers for servers. LOL. Another way is get one of the racket speed measuring racquets which make educated guesses about shot speed.

#### socallefty

##### Legend
If you are on a tight budget, it might be better to spend \$300 or \$400 on coaching lessons than on a radar gun. A coach will actually help you to serve better while a radar gun will just confirm that you serve too slow - I think you know that already

#### SystemicAnomaly

##### Talk Tennis Guru
The ball slows down a lot even by the time it crosses the net. The numbers you see on TV are measured right when it's hit. So you won't get comparable numbers to the pros by calculating the average speed of it in flight. Maybe if you're filming in 120fps with a very well positioned camera to get a good measurement of distance between contact and crossing the net you could do ok.
The numbers I've seen for a 120 mph Sampras serve had the pre-bounce speed in the 80s.

The serve speeds you see on courtside digital displays are measured just as the ball leaves the racquet. Fortunately for returners, by the time the ball reaches them, air resistance and the friction of the court surface have diminished its speed by roughly 50 percent. Tennis instructor and analyst John Yandell has found that, on average, a 120-mph serve slows to 82 mph before the bounce, then to 65 mph after the bounce, and finally to 55 mph at the opponent's racket.

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#### solarflair

##### New User
If you are on a tight budget, it might be better to spend \$300 or \$400 on coaching lessons than on a radar gun. A coach will actually help you to serve better while a radar gun will just confirm that you serve too slow - I think you know that already
Haha yeah--I'm not really looking for a radar gun at the moment. Just looking for a simple way to guesstimate my service speed within 10 MPH. A coach would help I'm sure but I'm on a budget.

#### ChaelAZ

##### G.O.A.T.
I bought a Bushnell radar gun a long time back. Maybe +/- 5mph at it's worst, but it has been consistent at reads. Think I paid \$70 at the time on a Black Friday sale. They probably have newer models that are better, but also probably a little bit more \$\$\$. Yeah, the frame calculation from video gets you in the ball park, but if for some reason you really want to know speeds having a radar gun is the only way to go.

#### SystemicAnomaly

##### Talk Tennis Guru
Haha yeah--I'm not really looking for a radar gun at the moment. Just looking for a simple way to guesstimate my service speed within 10 MPH. A coach would help I'm sure but I'm on a budget.
How about a shot speed app on that expensive iPhone you don't have.

#### ChaelAZ

##### G.O.A.T.
I bought a Bushnell radar gun a long time back. Maybe +/- 5mph at it's worst, but it has been consistent at reads. Think I paid \$70 at the time on a Black Friday sale. They probably have newer models that are better, but also probably a little bit more \$\$\$. Yeah, the frame calculation from video gets you in the ball park, but if for some reason you really want to know speeds having a radar gun is the only way to go.

Dang, just looked and they still sell the same gun (Velocity) and it is like \$150 now.

#### Chas Tennis

##### G.O.A.T.
I bought a Bushnell radar gun a long time back. Maybe +/- 5mph at it's worst, but it has been consistent at reads. Think I paid \$70 at the time on a Black Friday sale. They probably have newer models that are better, but also probably a little bit more \$\$\$. Yeah, the frame calculation from video gets you in the ball park, but if for some reason you really want to know speeds having a radar gun is the only way to go.
If you want to estimate ball speeds from your old videos and know your frame rate you can use the ball diameter as a reference length. This works accurately for camera angles perpendicular to the ball's trajectory. It is not so bad for off perpendicular, if the angles are small. 10-20 degrees off might be pretty accurate.

A simple way to think about it is - you can determine ball speed by how many ball diameters the ball has traveled in one or more frame times. In other words, taking a video from the side could end the long threads of BS on serve speeds.

This is not as convenient as a speed gun. But everybody has a smartphone now.

Wait! Is there a way to single frame on a smartphone?

My camera with high speed video mode steps single frame.

#### Nicholas Noker

##### Rookie
Look at other players if your level.
Say...4.0. Most hit 1st serves 80-90.
If your serve is faster, and scares them, you might hit 100.
2nd, swing as fast or faster, add spin, and should hit back wall by 2nd bounce every time....70 mph
What if the ball hits the fence on the first bounce?

#### solarflair

##### New User
How about a shot speed app on that expensive iPhone you don't have.
lol

Sent from my Jitterbug Smart 2

#### LeeD

##### Bionic Poster
1st bounce...light balls, hot weather, tall server, cab be 85 mph.
1st bounce...heavy balls, cold weather, slick coats can be 100 mph

#### Harry_Wild

##### G.O.A.T.
Go to a private tennis academy or USTA owned facilities and serve. Speed show up on the screen.

#### Topspin Shot

##### Legend
Take a video of your serve and post it here with your guess of its speed. Then average your guess with TT's consensus, and that's your actual serve speed.

#### SystemicAnomaly

##### Talk Tennis Guru
Go to a private tennis academy or USTA owned facilities and serve. Speed show up on the screen.
Better yet, enter the pro tournament at Wimbledon. Make certain that you play, at least, one of your matches where a radar gun is used.

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#### jered

##### Rookie
Swing app is decent for a comparison even if it is lowballing serve speeds you can at least compare first serve speed to second serve speed to get an idea of the delta in velocity. Pro men average about 70% of their first serve on the second serve but it typically has a lot more spin and shape to it.

More important is you can see where you are serving and how the opponent is responding so you can improve your serve decisions on where you serve to.

#### Oval_Solid

##### Semi-Pro
someone compile video of pro serves 100 to 120 mph then just record yourself and play your video next to the ones of the pros and match the one were the ball reaches the net at the same time for ball speed

#### SystemicAnomaly

##### Talk Tennis Guru
someone compile video of pro serves 100 to 120 mph then just record yourself and play your video next to the ones of the pros and match the one were the ball reaches the net at the same time for ball speed
Got to give you brownie points for creativity. Kudos.

#### Chas Tennis

##### G.O.A.T.
Here is an example of measuring serve speed with a video camera. These are instructions for measuring using the ball diameter as a reference length. This was a little more complicated because I did not have control of the camera alignment for the video and the ball trajectory was going away from the camera as the ball flew.

In this case, the uncorrected measurement was 56 MPH. The ball trajectory and camera were not well aligned. The measurement was corrected for the this angle giving a serve speed of 64 MPH. Kick serve.

The video is made with some text boxes that only appear on one frame. Stop on those frames to read them. This video pauses for 4 seconds on each frame with the brief text boxes. Normally, to move one frame on Youtube use the "." and "," keys. To get by the 4 second pauses use the video slider and "ms" time scale. (4 sec = 120 clicks of the "." etc.).

Closed Racket Angle before Impact

The closed racket angle should be videoed so that the racket is seen edge on to the camera just before impact. The measurement would be more accurate.

I put a 90 angle in the video, up from the court line, to act as a plumb line near the racket. See frame at 4 ms.

The racket angle at roughly 16 d. looks more closed than the 9 degrees that we measured in earlier serves. That closed racket face angle is one thing we were after for the bounce to the right.

But in the earlier serve comparing to Stosur your son was duplicating Stosur's kick serve technique very closely. I can't tell if anything changed when the camera angles change.
---------------------------------------------------------------------------------------

Measuring ball speed.

Measure the ball diameter on your computer screen before it is impacted - no ball distortions from impact. This will give a calibration of how many millimeters on your computer screen equals the ball diameter, ~ 2.6", in real space. You then can use this calibration and how far the ball moves in a known time to measure ball speed. However, the server was very wide on the baseline and served to an unknown spot in the ad court. If the camera were more aligned perpendicular to the ball's trajectory, the measurement will be more accurate.

From the image at

Frame at 0 ms - I measured the ball as 6 mm on my computer screen.
C - calibration factor

6 mm X C = 2.6" ball diameter
C = 2.6"/ 6mm
C= 0.433 "/mm The screen is calibrated near the impact.

Frame at 12 ms - ball position at 12 ms, Measure from center of ball.

Frame at 33 ms - ball position at 33 ms. Measure to the center of the ball.

I measure on my computer screen that the ball moved 48 mm.
D = 48 mm X 0.433 "/mm = 20.8"

The time, t, was 33-12 ms = 21 ms or 0.021 sec.

Velocity = D / t
V = 20.8" / 0.021sec
V = 990 "/sec (A useful conversion to remember is that 100 MPH = 1760" per second.)
V = 56 MPH, the component of forward ball velocity as seen by the camera. This 56 MPH speed would increase if the camera had viewed perpendicular to the ball's trajectory.

(Convert "/sec to MPH by entering "990 inches per second to MPH" in the Google search box. (The Google search box works like a calculator).)

By placing a video camera squarely on the side of a ball's trajectory, its velocity can be measured.
---------------------------------------------------------------------------------------------------------------

Correction to Measure Ball Speed

The server is serving from well to the ad sideline. I drew a line from the serve location to the right side of the opposite ad service box. Guessed the camera location and drew a line to estimate the ball trajectory. I measured some lines to get a correction.

The ball must have moved farther than seen across the camera's frame because it was also going away from the camera as it moved forward in the court.

The correction to speed is roughly 15/13 = 1.15.

V = 1.15 X 56 MPH
V = 64 MPH

In the Rod Cross article on the kick serve, he said that the high level kick serves are in the range of 80-100 MPH. See "Physics of the Kick Serve". Later I believe that Cross said in an interview that the 100 MPH used might have been on the high side. ?

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#### GuyClinch

##### Legend
Playsight is more accurate then the swing app IMHO. So if you can find one around where you live that would work.

SmartCourt Locator (playsight.com)

You then have to hook or crook your way into a court though. When I lived in California I got to play several times at the fancy Bay Club - and they have it. It's still pretty humbling - but not as bad as the swing app..

#### FRV4

##### Professional
Take a video of your serve and post it here with your guess of its speed. Then average your guess with TT's consensus, and that's your actual serve speed.
Yeah right, I had both frame counts and a radar tell me my serve was over 110. The same radar told me my baseball pitch was 62 and this was a slower reading than what I got with the pocket radar ball coach that I purchased later for baseball (63 held at an angle for a couple of pitches, so probably like 67, but that doesn’t matter). People in the thread were telling me my serve was as low as 70s. When it comes to serve speed, the experts on here are just about the worst. OP needs to just get a camera to do the frame count thing or a radar and just keep the results to himself to avoid getting heated.

#### WildVolley

##### Legend
Yeah right, I had both frame counts and a radar tell me my serve was over 110. The same radar told me my baseball pitch was 62 and this was a slower reading than what I got with the pocket radar ball coach that I purchased later for baseball (63 held at an angle for a couple of pitches, so probably like 67, but that doesn’t matter). People in the thread were telling me my serve was as low as 70s. When it comes to serve speed, the experts on here are just about the worst. OP needs to just get a camera to do the frame count thing or a radar and just keep the results to himself to avoid getting heated.
You have to separate the wheat from the chaff here. A few characters here lose their minds whenever an amateur says he can serve over 100mph, which is why you'll sometimes see low-balling of serve speed videos. That and it can be difficult to judge speed based on online video, given different frame rates, angles, etc. However, there are knowledgeable posters here, if you take the time to recognize them.

The best way is still to find a friend with a radar gun and get him to measure some of your serves.

#### sureshs

##### Bionic Poster
Last weekend I got to play doubles against a guy and his 7th grade daughter (he wanted her to get used to different styles of play than the usual junior play she sees). He served 2 serves (in an entire set) which shocked us with the speed which I guess would be more than 100 mph. But the way I remember them, apart from how the ball came at me of course, was his SWING SPEED. I remember that as a returner, the speed with which he swing his racket from trophy to impact was to me more revealing than the ball speed (I returned both serves very well by actually swinging back fast at them, to my surprise).

#### Chas Tennis

##### G.O.A.T.
This video illustrates the basic principle of measuring velocity with a video camera. I recommend the video. It starts at the velocity measurement. View in Youtube to hear sound.

To measure ball speed use the "undisputable method" - measure the time to travel a given distance -

I found the video interesting.

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#### Chas Tennis

##### G.O.A.T.
Measuring ball speed with a video camera. Step through single frame to measure the positions of each ball. Use the period & comma keys to single frame on Youtube.

This was done some time ago. The video camera was at 240 fps I believe. The shutter speed was very fast to reduce motion blur. The ball appears distorted because of Jello Effect, an artifact of video cameras that scan one line of the sensor array at a time.

I believe my fingers indicated 4 & 6 for the speed settings on the ball machine. ?

Ideally, you align the scale with the ball's trajectory before or after the serve. Small angle differences, 10 degrees, cause very small inaccuracies.

If a scale can't be used, for example for videos on the internet, the diameter of the ball can be used as a length calibration instead of a scale. Measure ball diameter in a direction perpendicular to the ball trajectory so that the motion blur is minimal.

The first ball position to measure is the one after contact with the racket has ended.

SEARCHBALLSPEED\$

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#### Bagumbawalla

##### Legend
Speaking of service speed-
Well, I don't remember how long ago this was, but
at one time Denny's put timers (the kind with sand)
on the table, and if all the sand emptied before your order was served,
then it was free. Don't think this promotion lasted very long.