Is there a inexpensive way to measure serve speed?
- Thread starter flargosa
- Start date
Dartagnan64
G.O.A.T.
If the opponent doesn't move before your serve hits the back fence, you have a good serve speed.
TBH serving is more about placement than speed so I never understand people obsession with their serve power. I can ace people with my 50 mph serve if I hit my spot.
To answer your question, a radar gun is the only quick way to get an accurate read but it requires money and another person. I've tried cell phone apps but they are inaccurate and fiddly. Play Sight courts are another way if you have one available to you.
TBH serving is more about placement than speed so I never understand people obsession with their serve power. I can ace people with my 50 mph serve if I hit my spot.
To answer your question, a radar gun is the only quick way to get an accurate read but it requires money and another person. I've tried cell phone apps but they are inaccurate and fiddly. Play Sight courts are another way if you have one available to you.
Tennis Player
New User
Serve next to one of those radar signs like Dennis Quaid did in "The Rookie."
Irvin
Talk Tennis Guru
1 Mile/hour is 5280'/3600 sec or 1.46667 feet per second. Distance from baseline to baseline is 78' so to serve at 100 mph your ball must travel from baseline to baseline in 0.53182 sec.
https://appadvice.com/app/speedclock-video-radar/400876654
EDIT: Find a coach for a travel fast pitch softball or baseball team and ask to borrow his radar gun.
https://appadvice.com/app/speedclock-video-radar/400876654
EDIT: Find a coach for a travel fast pitch softball or baseball team and ask to borrow his radar gun.
I found a Radar called Velocity speed gun in Amazon. It's use for tracking baseball, tennis and softball. Accuracy is +/- 1 MPH. I guess I can buy new for $53, then sell used for $45, total cost my end should be about $10 - $15. Maybe the guys in my league might want their serves measured for fun as well.
movdqa
Talk Tennis Guru
Could you convince your club to buy one?
It's going to be hard to convince my club to buy it. It serves no purpose other than let you know how hard you hit the ball. I would think a few of the guys would want to use it once or twice though.
movdqa
Talk Tennis Guru
My club replaced one of the tennis courts with a hockey rink. They're pretty cheap. So I couldn't convince them to buy one but I could just buy one and donate it.
Another club that I know is tennis-only. No gym, no pool, no treadmills; just tennis. I could probably convince them to buy one.
UCSF2012
Hall of Fame
You don't need a radar to tell you whether your serve speed drops by the 3rd set. Someone else has to gun you too. You can't operate a radar and serve at the same time.
Your brain should be thinking the entire match whether shifting your toss location is needed to keep the ball in.
Your brain should be thinking the entire match whether shifting your toss location is needed to keep the ball in.
SinjinCooper
Hall of Fame
Find a guy who says he serves 120 and compare it to him. If you serve the same, you're at 80 mph.
racket king
Banned
It will give you a rough idea, but with most cameras it won't be that accurate because they'll shoot at 30fps, so depending on which frame you decide to start and stop counting, you could have a margin of error of 10-20mph or thereabouts, because at 30fps there won't necessarily be an exact point in time where there's a frame showing exact contact with the strings (start) and exact contact with the ground (end). The faster the serve, the greater the margin of error. A higher fps video eg. 60fps,120fps etc could possibly overcome this though. You'd also have to measure exact T serves or exact corner serves only to try and reduce errors caused by the variation in distance measured, as well as knowing how far you toss the ball into the court....
There is a way of doing it accurately, but the whole thing needs to be setup carefully so as to minimize the margins of error.
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Of course it is not perfect, but if you have a phone that support slow motion 60pfs or even 120pfs (which may phones today do), you can get a pretty good estimate, especially if you averages out a few serves.
Chas Tennis
G.O.A.T.
The basic way to measure velocity is to measure distance traveled in a known time. Video camera mostly have a fixed frame rate, in the US often 30 fps. Measure the distance traveled in one frame time, don't include impact, but the next two frames after impact. (Smartphones may have an issue, they sometimes reduce frame rate for low light levels.)
With care I believe that a video camera can as accurate as a radar. But video does not calculate and display the speed, instantly, you have to measure distance in a video frame. Video is useful for occasional velocity measurements.
With care I believe that a video camera can as accurate as a radar. But video does not calculate and display the speed, instantly, you have to measure distance in a video frame. Video is useful for occasional velocity measurements.
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racket king
Banned
60/120 would potentially allow for more accuracy but there's still user subjectivity and spread of variation in the way that frames are counted and where you start/stop the counting though the range of variation should be less. They use specially designed radars at the Slam tournaments for good reason - they're objective every time. I wouldn't mind trying 120fps out of curiosity though to see if the spread of user variation is less - 30fps just doesn't have enough frames to be truly accurate as you're having to estimate split frames which isn't objective.
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Chas Tennis
G.O.A.T.
You can measure from two frames. At 30 fps, an object at 100 MPH moves 59" in one frame time.
SystemicAnomaly
Bionic Poster
It's gonna take longer than that to reach the opposite baseline. First, the serve does not usually travel perpendicular to the baselines so the horizontal distance will be greater than 78'. In addition, the serve has a vertical component as well as 2 horizontal components. Since the ball is traveling in 3 dimensions (up, down, left/right and forward), the total distance it travels will be greater than just the forward horizontal distance.
Even more significant than the distance traveled is that fact the the 100 mph is slowing down. Serve speeds are typically measured just as the ball comes of the strings. That 100 mph serve loses about half its speed by the time that it reaches the opposite baseline. Just before the bounce, the ball speed probably has already diminished more than 20% due to air drag (friction) during its flight. It loses a significant amount during the bounce itself. It might be traveling somewhere in the neighborhood of 60 mph just after the bounce. More air drag as the ball travels from the bounce location to the far baseline.
racket king
Banned
You've completely missed the point. Or haven't understood it.
jm1980
Talk Tennis Guru
His little demo showed it
jm1980
Talk Tennis Guru
I was just going to write this. There was a graph showing a couple of Fed's serves, both initially struck at 126 mph. They were travelling at 43 - 50 mph by the time they reached the returnerIt's gonna take longer than that to reach the opposite baseline. First, the serve does not usually travel perpendicular to the baselines so the horizontal distance will be greater than 78'. In addition, the serve has a vertical component as well as 2 horizontal components. Since the ball is traveling in 3 dimensions (up, down, left/right and forward), the total distance it travels will be greater than just the forward horizontal distance.
Even more significant than the distance traveled is that fact the the 100 mph is slowing down. Serve speeds are typically measured just as the ball comes of the strings. That 100 mph serve loses about half its speed by the time that it reaches the opposite baseline. Just before the bounce, the ball speed probably has already diminished more than 20% due to air drag (friction) during its flight. It loses a significant amount during the bounce itself. It might be traveling somewhere in the neighborhood of 60 mph just after the bounce. More air drag as the ball travels from the bounce location to the far baseline.
The amount of speed it loses with drag (air resistance) depends on how fast the serve is. The faster it is, the stronger the drag.
The amount of speed it loses after the bounce also depends on the surface and the spin. The flatter the serve, the more speed it loses
bigserving
Hall of Fame
Just do like most players do and make it up. That way, you won't be as disappointed.
Bender
G.O.A.T.
The only way you can ace someone with a 50 mph serve is by completely fooling your opponent with regards to direction or hitting it with good side spin. In the case of the former, then your disguise must be incredible or your opponent blind. In the case of the latter, that means you already have the strength to hit booming serves, only that you have redirected most of that potential power to spin.
Being able to serve hard is important because it's a good indicator of the 'raw materials' or 'resources' you have at your disposal. Whether you choose to put all that into raw speed or redirect some of that into spin is a matter of personal choice, but it's far better to be able to hit with monster power on any shot than not because you can always afford to lose something that you have too much of. It's a bit more difficult however to add something that you do not have much of in the first place.
Bender
G.O.A.T.
Thanks to delusion, I myself hit 144 mph second serves at 5,400 rpm.
gplracer
Hall of Fame
Try this app http://www.tennisservetracker.com
Also, what about a Sony sensor? They sell them here on TW
Also, what about a Sony sensor? They sell them here on TW
scf
Semi-Pro
It's not clear to me what the premium in-app purchase does? Is it usable without this upgrade?
bigserving
Hall of Fame
That is soooooo wood racquetish. With graphite, I am up to 155 mph and 6500 rpm. Roddick retired because he could not match my pace!
Calibrating my new "laser radar gun" today. May have to update those stats later.
movdqa
Talk Tennis Guru
Is that you Sam?
Harry_Wild
G.O.A.T.
Ask a division I player to return your serve! He/she will tell you how fast it is!
bigserving
Hall of Fame
It might be. It depends on who Sam is.
Tennisanity
Legend
I'm surprised there isn't some app for this. With slow motion mode can't the ball speed be measured at least roughly?
Dartagnan64
G.O.A.T.
This doesn't take into account ball velocity reduction due to court friction and air resistance. Your 100 mph serve is likely traveling less than 50 mph at the opponents baseline.
Dartagnan64
G.O.A.T.
No just play slower, less competent players. And be able to hit both corners. Most 3.5's have such a terrible BH that they'll shade over to that side. Especially if you send your serves that way frequently. Then when you need it, serve out wide with slice to their forehand. Amazing how often you can ace the average rec player if you can do that.
Speed without placement while a good indicator of how tall you are and how young your shoulder is, is not the most important thing in tennis. It is a resource for sure, but you better be able to learn to place it. I've beaten many guys with howitzer's that hit 10% of their first serves in, right at you. Once you get a bead on those serves, returns aren't that hard because they don't make you move.
But guys that can hit the corners, even if slower. They'll keep you gusessing all game long and provide a more significant challenge.
Irvin
Talk Tennis Guru
There were 3 options there to measure speed how come both of you only read one?
SystemicAnomaly
Bionic Poster
Had READ your whole post. Only had an issue with the 1st option.
jm1980
Talk Tennis Guru
Probably because it's the one that is completely wrong
Irvin
Talk Tennis Guru
Do you think distance divided by time is not a good cheap way to measure speed"
jm1980
Talk Tennis Guru
No, because it oversimplifies everything, ignores air resistance, friction with the court surface, and the trajectory of the ball.
Like it's been said in this thread multiple times, a serve that is initially hit at 120mph will be travelling at less than 50mph by the time it reaches the opposite baseline.
What you're doing is, at best, estimating the average speed for the serve traveling baseline to baseline. But serve speeds are supposed to be measured at contact.
