How to measure serve speed?

Discussion in 'Tennis Tips/Instruction' started by sanitarium, Jun 17, 2004.

  1. sanitarium

    sanitarium Rookie

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    anyone have any ideas besides a radar gun?


    Possibly stopwatch as soon as it crosses the net or something? but it just seems very hard to time accuractely, and 0.1s makes a huge difference...
     
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  2. kevhen

    kevhen Hall of Fame

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    how high up on the fence it hits is another way. I usually figure about 90mph if it makes it to the fence before it's second bounce and maybe about 5mph more for every foot higher up the fence. Mine usually range from 2-3 feet up and I have been clocked between 100-105mph. Indoors, the curtain is closer to they will hit higher by a foot or more for the same speed.
     
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  3. kevhen

    kevhen Hall of Fame

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    Also if you balls typically get stuck in the fence then you might be hitting around 90-100mph. If your balls are going through the fence then you are probably well over 100mph.
     
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  4. Verbal_Kint

    Verbal_Kint Rookie

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    That's gambling though kevhen, spin etc vary as well. High speed video, you know how much time passes between frames, measure the distance the ball has travelled, calculate distance/second=speed.

    Marnix
     
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  5. TennsDog

    TennsDog Hall of Fame

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    Kevhen, you cannot count on that method being very accurate at all. Spin, angle, flatness of the ball, all of these affect how the ball will react in relation to the fence. I hit topspin serves and my goal is to make the ball hit as high up the fence as possible, sometimes 3 feet, but they are nowhere near 100 mph, 60 at best. Sticking in the fence also relates more to spin than speed. I can have a 35 mph forehand stick because of how much spin I put on it. I don't know that there is really any easy way without a radar gun or other rather expensive equipment to judge ball speed.
     
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  6. Reza

    Reza New User

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    nothing works other than a radar gun. The ball slows significantly even by the time it gets to the net, and serve speed is based on initial speed, not the average speed from the point of contact to the net. Its that simple----there are too many other variables.
     
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  7. kevhen

    kevhen Hall of Fame

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    I am talking a flat or almost flat serve. I know how far up mine hits and about how fast it is based on radar. It also depends on how deep in the box the ball lands. My kick serve can land 3-4 feet up the fence at about 90mph. I am not sure that a 60mph kick serve could land 3 feet up the fence. You must have some amazing spin on that or the surface you play on has a lot of bite to it. I think my slow kick serve would barely get to fence if it landed in the service box and it has quite a bit of spin on it.
     
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  8. gmlasam

    gmlasam Hall of Fame

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    Even so your theory is based on flat serve, its still not very reliable to determine the speed of the serve. There are too many variables that need to be considered, the distance of the fence from the court, the property of the balls used, (new ball, old balls, types of core in the ball..etc.), the surface of the court, and so on. The only true, reliable, and practical way to determine service speed would be a radar gun.
     
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  9. kevhen

    kevhen Hall of Fame

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    The question was how to measure serve speed without a radar gun. That is about the best way I know how besides just eyeballing from years of experience.
     
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  10. Kobble

    Kobble Hall of Fame

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    Well, how about we cut out some of the variables.

    Balls- Penn championship Hardcourt $2.00 a can.
    Surface- Hardcourt used at most parks.
    Fence- Whatever is standard for parks. Salman measured them at 15 feet.
    Serve type- Flat

    Has anyone clocked their serves under these circumstances? I know it is still not perfect, but at least you can an idea.

    Approximately how high did 80 mph land?
    Approximately how high did 90 mph land?
    Approximately how high did 100 mph land?
    Approximately how high did 110+ mph land?


    On video I have seen 82 mph hit 1.5 to 2.0 feet. This was on hardcourt in a Braden video. I have never been clocked but Many trained eyes said I served well over a 100 mph, and the balls landed about 3 feet to 4 feet up.
     
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  11. Kobble

    Kobble Hall of Fame

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    Also, does anyone have the stopwatch method conversions?
     
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  12. Verbal_Kint

    Verbal_Kint Rookie

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    I have a better one. Get an old camera, set the shutter time to a given, and calculate from the length of the blur. ;)

    Marnix
     
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  13. kevhen

    kevhen Hall of Fame

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    I tried getting my slow kick serves to bounce to the fence last night and was like 5-10 feet short especially when they went out wide. I know my slice will never make it to the fence, but my hard kickers will land 3-4 feet up. I only use Dunlop or Wilson balls. Penns usually come out of the can flat. Why do people use Penns anyway?
     
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  14. djbrown

    djbrown Rookie

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    There would be no way to do this accurately. Human reaction time varies too much to be able to start and stop a stopwatch that quickly when even a tenth of a second would matter when determining service speed.

    It's right at 60" from the baseline to the opposing service line, right? That's equivalent to the distance between home plate and the pitchers mound in baseball. You can get a decent idea on how fast you serve by comparing the times for each. Nothing much more accurate than greater or less than 90 mph though (the speed of an average MLB fastball)
     
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  15. Anonymous

    Anonymous Professional

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    I didn't measure it, it was a guess. I think it is 18 ft though. If i remember I will measure it tommorow.
     
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  16. Datacipher

    Datacipher Banned

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    Exactly. I know from experience that there are so many variables that can have effect. It can give you an idea along with just visual estimation...but that's about it...it is not a consistent measure at all. Particularly I think the weather...humidity and heat can really influence ball bounce.

    My serve tops out around 125mph, yesterday I hit a flat serve that stuck in the fence aproximately 6 feet up(I'm not convinced it was one of my fastest...but was probably 115 anyway)....but the weather was very hot and very dry. On a damp cold day....cannot even approach this even when radar shows the same speed...
     
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  17. Datacipher

    Datacipher Banned

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