# My serve. 100 + MPH with video and radar

Discussion in 'Tennis Tips/Instruction' started by drakulie, Sep 19, 2006.

1. ### Mike CottrillHall of Fame

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Yes and no. NASA calls it fuzz drag. The fuzz drag has a different effect as you described. But a pure smooth ball versus a non smooth one. The smooth one will have more drag. IE this is why a golf ball has dimples.

Thanks for the information. I'm just trying to see how close this est. is. I have 240fps video. I calculated the average speed to bounce. Ball was just about on the line so I calculated at using 60ft travel distance. I just rounded the distance because of the downward distance ball has to take from strike to ground. That gives me an average. Maybe many unknowns to find max velocity?

Thanks guys..

2. ### Mike CottrillHall of Fame

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Thanks. This helps some. If you have an average speed from contact to bounce. Using Petes numbers, any way to find peak V?

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4. ### MotoMDNew User

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I would guess that the more frayed the ball, the better the effect of the spin. But I have no proof of it, just a guess.

5. ### maverick1Semi-Pro

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Mike,
(I saw in your profile that you are an engineer). email me if you are interested in pursuing this. I thought about this problem, and I think it is solvable. But I don't fully trust my math. I studied diff equations when Borg & McEnroe played THAT tie-breaker.

6. ### Mike CottrillHall of Fame

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Yea, I took it not that long ago. I took it in 86 I think. I'm just lazy.. but interested as long as I do not have to go into deep math.

7. ### drakulieTalk Tennis Guru

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Mike, Maverick;

You guys have me curious. Later this week when I get a chance I am going to put the radar on the baseline to see how fast the serves are going when they pass the baseline. I will post a video.

8. ### Mike CottrillHall of Fame

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That will be interesting. Also, if you calculate the number of frames from your hit to first bounce and distance to bounce, that can help to see how far I'm off on the calculation. Like if you go down the tee and are a few inches or foot from the T, then 60' is close enough. You might be able to do this with the video you already have. Some of these video players are finicky though and frame counting can be a chore. For the one you hit 108 can you count the frames and distance? that would be great. If it hit up the line some, take a guess on how short from 60’ it is. Post that if you can. I will plug it in and see what it shows. Maverick is working on a more precise formula.
Thanks
Mike

9. ### tempura_MAKIRookie

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I hit 100+ consistently when I try, i have been clocked 2 different times, and my serves look alot like the speed of drakulie's... if anything slower, because my highest was 102 mph, im always like upper 90's.

10. ### maverick1Semi-Pro

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Exactly.

I am working on a formula to find speed given the frames between the hit and the bounce, and the approximate distance. With my limited math/physics skills, there is no guarantee I will come up with anything useful.

I had a match last night, so didn't work on it. But thanks to this thread, I have been focusing on the serve, practiced it for 90 minutes on Sunday, hit a personal record number of aces yesterday (about 6) including 2 in the last game. Never hit an ace and shook hands before! Felt a bit like Sampras except my serve still doesn't quite reach 90 mph, but I have become better at hitting near the T because that is what I did in practice in order to measure the speed effectively

11. ### maverick1Semi-Pro

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I couldn't resist working this out and wasting company time.

If your own serve took t frames in standard 30 fps video to cover a distance of d feet in the air,
your serve speed in mph was:

(exp( d / 5280 * 28.3) - 1 ) / 28.3 / (t / 108000)

To make it easier, here is a table converting from the number of frames of standard 30 fps video it took for a down the middle serve to land on the T.
Frames Speed
11 -> 131.6
12 -> 120.6
13 -> 111.4
14 -> 103.4
15 -> 96.5
16 -> 90.5
17 -> 85.2

The function "exp" is available in the Windows calculator after you choose Menu option view->scientific.

Later, I will post my full derivation for "peer review"
The formula relies heavily on the fact that a 120 mph slows down to 87mph over a distance of 60 feet as reported in the link boojay posted.

12. ### Mike CottrillHall of Fame

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Can you replace the 30ffps with a variable or cacluate with 240fps? I assume this is V peak?
Thanks
Mike
Like to see the derivation .
Mike

13. ### no skillzRookie

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Hey rick,
my ankle has gotten even worse.
So I dont see myself playing for a while, however I am looking foward to more serve videos.

14. ### maverick1Semi-Pro

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Just divide the number of frames by 8 and plug in without any rounding. eg: 106 of your frames would be = 13.25 normal frames implying a speed of 109.3 mph.

If you want a variable, here:
(exp( d / 5280 * 28.3) - 1 ) / 28.3 / (t / (frames_per_sec * 3600 ) )

I don't know what "V peak" is.

I will post the derivation, probably tonight. I have to decide whether to type it as text(will be hard to read), use Word equation editor, or scan an image of a handwritten page.

I am curious, how did you get hold of a 240 fps camcorder? I have a Sony HDR-HC3, which is pretty much state of the art in consumer camcorders, has a slow motion mode which is at best 120 fps, works for 3 seconds at a time, is not easy to use and requires bright daylight.

15. ### Mike CottrillHall of Fame

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Vmax. Sounds like that is what you calculated. I have the non HD version of what you have (Sony Handycam DCR-DVD505). It will do 240fps not 120fps ( well depending on interlacing). Resolution not so good, but frame rate is nice. To see all the frames, I have to use the HP Cyber Link Power DVD Player that came with the camera. And at times, it will not show all the frames. Sometimes it skips or combines them. I’ve wondered how much better the HD version is. Need to find a player that will display time/frame to see when this is happening. How do you like that camera? I like mine.

16. ### Mike CottrillHall of Fame

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I thought I was a little conservative with my assumptions. I was not to far off though .

17. ### maverick1Semi-Pro

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Yes, Vmax/Vpeak is what I calculated.

I am pretty happy with my camcorder. It was smaller/lighter than I expected. I got an OEM battery for \$40 that lasts 270 minutes, and the HD video is awesome. The main problem is they don't give you any software. I had to pay \$49 for Roxio, and that captures but doesn't let you edit HD or even play it! MS media player chokes on HD video. Luckily Realplayer works, but my PC is many years old, so it has trouble with playing HD.

The derivation is long, hairy and pretty far from the original subject of this thread. So I posted it here:
http://tt.tennis-warehouse.com/showpost.php?p=1165185&postcount=1

18. ### Mike CottrillHall of Fame

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drakulie,
What veiwer are you using?
Do you have WinDVD or Cyber Link Power DVD Player? You might be able to download a trail version of Cyber Link Power DVD Player and use it. There are step forward buttons on the veiwer.

Mike

19. ### drakulieTalk Tennis Guru

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Sorry, but you totally lost me. The video's were automatically downloaded to the kodak picture program that came with the camera. The camera is a kodak v610, and it says it records at 30 fps. I have tries to open the video in windows media player to no avail.

Also, the 108 and 105 serve I have deleted off my computer. The only 2 I have now are the 104 and 105 that I walk up to the radar.

But I will video myself again, including putting the radar at the baseline to see if it picks up the speed from there.

20. ### Mike CottrillHall of Fame

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what is the extension on the file the kodak camera down loaded. .mpg, .avi ?

21. ### drakulieTalk Tennis Guru

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Mike, I'm not sure, I have the program downladed on my computer at work so I will have to check tomorrow.

22. ### skuludoProfessional

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My best on that radar gun is 101mph with the radar gun about 15cm away from the net. Radar gun is on the same side as where the serve is coming from. Most of my serves are hovering around 86-94 range.

The 101mph did land in. My next closest was a 98mph which didn't make it over the net.
My 101 had bounced really low. Bounce height looked like 14cm. The 86s and 90s bounced were waist height

My second serves didn't get clocked by the radar gun probly because I am hitting the ball too high above the gun. The ones that did get measured was around 40-46 mph. Max second serve was 50 mph.

Height: 169cm 5'6

Strings: Looks like Head RIP Control
Tension: Unknown. Probly 3 months old
Balls: New can of Wilson Double Core balls

23. ### bribeiroBanned

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nice serve man, I really like the motion.

24. ### drakulieTalk Tennis Guru

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Thanks, I appreciate it. I am going to try and post some more serves when my foot is better.

25. ### drakulieTalk Tennis Guru

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Sorry to hear that. Let me know when you want to start hitting again. Hope everything else is well.

26. ### skuludoProfessional

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Anyone know how much speed was lost when the gun took it's measurement 101mph?

27. ### bribeiroBanned

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how long did it take you to serve like that?

28. ### drakulieTalk Tennis Guru

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Well, I started playing when I was around 9 and played competitively until 19 years old. Had 2 shoulder injuries where my shoulder came out of place twice, so I quit playing and did not pick up a racquet for 14 years.

Then started playing again about 2 years ago. So, it is hard to say how long it took me to serve the way I do. I actually use to serve much faster, and had more of a McEnroe type serve with my back completely to the returner. When I started playing again, I had to adjust my serve because of my shoulder, so I opened up my stance a little.

29. ### bribeiroBanned

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oh, so you've been playing for a loong time, no wonder you have a good serve.

30. ### skuludoProfessional

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That 101 record might be an error. Could have been 81. When I was walking up to the gun it registered my movement at 7 mph so I couldn't hit the recall button. I went out and hit a couple more serves and hit a 99mph. I hit that off a really low toss. Seems like the higher I toss the more kick I get, but it registers slower.

To me it didn't really look like it was any faster than my higher serves that cleared the net a bit higher.

Couldn't go over 99mph this time. I got the 99 reading a couple of times, but I just couldn't make it to 100.
Used Babolat Pure Drive Team Plus in this session because the strings were shredding in the Liquid Metal Radical Mid+.

31. ### skuludoProfessional

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In the manual it says something about wet balls effecting it. What about humidty say 81%?

32. ### drakulieTalk Tennis Guru

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People don't realize how hard it is to get to the 100 mark, or for that matter even 90+. And then, get the ball in the box consistently with spin and placement. You'll get there. Just remember to swing easy. The harder you try to swing the slower the pace.

By the way, I haven't noticed any problems with humididty. I do remember reading about wet ball in the manual effecting the readings.

33. ### tennis_nerd22Hall of Fame

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drakulie, when your foots better, do you think you can hit the 110, or even 120 mark? if so your my new serve idol...

34. ### maverick1Semi-Pro

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Hey Drakulie,

I am just trying to get to the 90+ range. Do you have any advice for me?

I posted a video in this thread:

A lot of people gave advice, including one who says the "whip" the arm faster. That sounds contradictory to your advice of "swing easy".
You have a serve that is certifiably 20 mph faster than mine, so I'd listen to you.

35. ### drakulieTalk Tennis Guru

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Mav, I posted on your thread, page 2 post # 30. You probably didn't see it because it happened to be the last post on that page. I think your "swing speed" is fine, and yes I think you should "swing easy".

I actually tested this theory out with the radar. The harder I tried to swing the slower the serves were. When I relaxed and "swung easy" the serves were faster.

36. ### drakulieTalk Tennis Guru

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My foot makes it easier for me to serve, definitely helps with spin, and launching me into the court.

I hit 115 a few months back, when the director at the league I play in radared my serve with a "Bushnell" speed gun. The fastest I have ever been clocked was 118 when I was in college. I doubt I could ever hit 120, but defintiely serve in the 100-110 range throughout a match. One of the problems I have with speed over 110 is that I put a lot of spin on the ball, including what people would consider a "flat serve", so the spin slows down the ball.

37. ### skuludoProfessional

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I tried to do it again and I only made it to 98MPH. (Down the T on deuce side. Serve landed in.)

Couldn't make it back to 99mph today. Hit probly 3 or 4 98s. Best I could do.

My stomach is in pain from all the serving I did.

I thought the Bushnell's gun capped off at 110MPH for tennis. Is that not true?

38. ### War Safin!Professional

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I agree - not only does Sampras possess the greatest serve ever but also the greatest action, too. I can't see why no-one else copies it.

To be fair though, didn't Sampras' slightly longer arms give him more forearm/wrist snap than other?

39. ### SlazengerProfessional

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Well if you factor in the error margin of the radar you used, you might just have hit a 101mph serve

40. ### maverick1Semi-Pro

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Have you tried placing the Radar gun closer to you?
I think you said that you put it very close to the net. Does this gun have a range of 39 feet? If not, moving it closer will definitely help record a faster speed. A similar looking radar gun I bought 7/8 years ago advertised a range of only 15 feet.

If you move it too close, the reading will drop because the line of ball's travel would be at too much of angle to its line of sight. This problem can be mitigated if you put it on a stool or a step ladder such that the serve passes just above it.

Obviously, Neither is cheating. The Radar guns at professional tournaments are essentially free of both these issues that understate speeds.

41. ### War Safin!Professional

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Darkulie - how long can you sustain these speeds for?
Using a Prostaff, strung at 70lb I'd have thought would be hard to keep serving around 90-100mph for longer than 90mins - 2 hrs...

42. ### boojayHall of Fame

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hey drak, I haven't been keeping up with this thread so maybe this was already answered, therefore I apologize in advance if it has--is there a cheaper place to get this radar other than optics? I was going to place an order, but in total it would cost me well over \$200 + potential customs fees (I'm from Canada) and I was like....holy sh|t.

i'm thinking i could probably make the money back by charging a small fee to customers for using it until it paid for itself, then letting people use it for free.

43. ### drakulieTalk Tennis Guru

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An entire match, or 2-3 hours. Actually as the match goes on, I start getting more comfortable, and it becomes a little easier to swing freely. I usually serve serve slower at the beginning of matches.

44. ### drakulieTalk Tennis Guru

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Boojay, I'm not sure. but search the interenet or go to E......Bay.

45. ### drakulieTalk Tennis Guru

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46. ### drakulieTalk Tennis Guru

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47. ### ZPTennisSemi-Pro

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very interesting. would that particular radar be able to pick up the serve if you had a person standing right behind you holding it? Ill bet you go over 110 if you do this

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49. ### skuludoProfessional

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I tried putting the gun closer and it won't clock the serve. When I put the gun closer I would get lower readings if it did manage to clock the serve. Also I tried standing pass the baseline to serve and got a low reading too. I was thinking of having someone hold up the gun, so the serve can be clocked earlier. I'll try this when I get a chance to hit with my hitting partner.

Today I placed the gun at the same location by the net and scored 98mph with a 88 square inch racket. Racket was Yonex RD Ti 70 mid. I've tried a 115 square in racket called Tecno Pro Control 6.2 and got the same speed too. With the Babolat Pure Drive Team Plus I also scored a 98 and 99. There really is no difference in power when I change rackets for serving.

Strings: Tecno Pro, Babolat Superfine Play gauge 16 (Strings are at least a year old)
Babolat PD+, Big Banger 5 Star 50lbs
Yonex RD Ti 70, (Babolat Pro Hurricane Tour gauge 16 50lbs)

One notable difference is in mishits. I would score a 86mph if I mishit with the Babolat Pure Drive Team Plus. Most of my mishits will go in at the 80s.
Mishits with the RD Ti 70 would score in at the upper to mid 70s. 79mph was max on a mishit (A very bad one like near the 12 o clock position. I tossed the ball too high and swung too soon on that serve.)

I opened a new can of Wilson Titanium balls for this session.

Tried a 13.4oz I Radical OS and scored 99mph max on serve. Many of my serves were hovering the 90 range with I Rad OS.

--------------------------------------------------------------------------------------------------------------------------------------------
Rant/Frustration:

No matter how many times I try I'm stuck at 99mph. This is BS.

50. ### amit_aceNew User

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Personal opinion- best serve on BB postings

Of all the posts (video) i find ZPTennis serve the fastest and most effortless...
Just a comment...my personal view..