People here underestimating others serve speeds

Discussion in 'Tennis Tips/Instruction' started by Nickzor, Apr 1, 2014.

  1. WildVolley

    WildVolley Legend

    Joined:
    Jun 22, 2007
    Messages:
    5,687
    This is what we want to hear.:)

    If we can avoid having to construct a more accurate physics model with a bunch of differential equations, that's what we want to hear. Far easier to just have a model with a bunch of simplifying assumptions that can be tossed into an excel spreadsheet.

    What people need to understand at this point is that the potential error is mostly a factor of frame estimating when using low speed video (30fps) and incorrectly judging distance from ball contact to court bounce, rather than the simplifying assumptions of the physics model.
     
  2. Sid_Vicious

    Sid_Vicious G.O.A.T.

    Joined:
    Dec 21, 2010
    Messages:
    11,683
    Location:
    In The City
    Well said. I would much rather use this method than buy this thing for 300 dollars and get wild results like this


    https://www.youtube.com/watch?v=aX-_k2e6_Kc

    87, 98, 49, 46, 85, 84, 52 :lol:


    Although I'm positive these guys either didn't use the product correctly or it was broken. :lol:

    Even electronic speed guns can give numbers that are "too good (or bad!) to be true. Case in point, Federer's 52 mph serve at Wimbledon
     
    Last edited: Apr 4, 2014
  3. WildVolley

    WildVolley Legend

    Joined:
    Jun 22, 2007
    Messages:
    5,687
    My radar gun will sometimes lock in on the racket before the hit and give you a reading of 24mph on a 95mph serve. That's annoying, but it doesn't happen too often. That could have been happening on those very low misreads.

    That is sort of nifty little radar if it works well. It is easier to carry around than mine, which has sort of a gun form but does mount to a standard tripod for a camera.
     
  4. Sid_Vicious

    Sid_Vicious G.O.A.T.

    Joined:
    Dec 21, 2010
    Messages:
    11,683
    Location:
    In The City
    Yes, I agree. I have seen the results with the pocket radar for various other objectives like baseball pitches and golf swings. It seems like a great product, but I don't think I can justify spending that much money on it when I can get a good reading with a free app.
     
  5. 5263

    5263 G.O.A.T.

    Joined:
    Mar 31, 2008
    Messages:
    10,390
    I'm pretty confident that guy dropped a couple of those at over 100.
     
  6. LeeD

    LeeD Bionic Poster

    Joined:
    Dec 28, 2008
    Messages:
    35,688
    Yeah, his 2nd attempt seemed the fastest.
    Then he denigrates to some form of flat/slice, adding spin and mishitting a few, possibly trying too hard.
     
  7. treo

    treo Rookie

    Joined:
    Dec 5, 2004
    Messages:
    367
    Someone should develop a big target on a stand inside the service box with a barrier that will only break when a ball hits it at a certain speed. The barrier would have some kind of mechanism or it could be thick paper.
     
  8. jmnk

    jmnk Professional

    Joined:
    Jul 1, 2009
    Messages:
    982
    because I'm no PRO :)
     
  9. WildVolley

    WildVolley Legend

    Joined:
    Jun 22, 2007
    Messages:
    5,687
    Looking at your critique again, I think it is quite good. I'm going to stick with using my radar gun to measure serve speed.

    At some point in the future, I'll compare the frame-count model to my radar measurements. It will be interesting to see what a good topspin serve does to the inaccuracy.
     
  10. asimple

    asimple Semi-Pro

    Joined:
    Jan 23, 2013
    Messages:
    437
    This guy's serve seemed pretty close to the speed of most people's videos I saw which is leading me to believe that the frame count estimates near 120 are not accurate.
     
  11. ilovetennis212

    ilovetennis212 Professional

    Joined:
    Jul 16, 2013
    Messages:
    1,146
    Location:
    Tennessee
    Please someone back me up if I'm right.
    Pro's gun(high end) measure the speed of the ball right after contact is made.
    Our gun ($130 -$400) measure the speed of the ball when it's coming close to gun.
    That's why alway pro's gun measure result is little bit high.
    You can add 3 - 6mph to your gun.
     
  12. WildVolley

    WildVolley Legend

    Joined:
    Jun 22, 2007
    Messages:
    5,687
    This isn't necessarily true. There is a range issue with the SpeedTracX, the radar people set on the court in front of them. Because of the limited range, it tends to catch the ball sometime after impact.

    With the SportsRadar gun I have, you can set it on a tripod behind you, or have someone stand behind you attempting to hold the gun in line with your serve. In this case, the gun attempts to read peak speed over a period of time. Because the gun can be held feet away, range is not an issue. I tested range and found the gun was able to also read serves from the other side of the net.

    Not all consumer radar have the same ranges. So I don't feel comfortable in automatically adding speed.
     
  13. tennis_ocd

    tennis_ocd Hall of Fame

    Joined:
    Aug 17, 2011
    Messages:
    2,002
    That gun -- all commercial radar guns really, are very accurate at capturing speed. Issue with any gun that must be manually triggered is timing the trigger. It's pretty obvious when you've timed it right and picked up ball speed and when you picked up arm or racket movement. He caught the ball four times, arm or racket others. I think the frame rate thing and app is seriously flawed; even if knowing the precise frame count (time) and distance the best you can calculate is avg speed (without a guesstimate on speed lost to air resistance.) No one in tennis or baseball is concerned with avg speed; it's all off the racket or fingertips.

    shows how to use tiggered version of pocket radar:
    http://www.youtube.com/watch?v=x_KCra2I16s

    compares various radars with non-triggered version of pocket radar:
    http://www.youtube.com/watch?v=VIfII_gSZ_Y
     
  14. tennis_ocd

    tennis_ocd Hall of Fame

    Joined:
    Aug 17, 2011
    Messages:
    2,002
    Apparently not enough as I've repeatedly stated rec players can and do hit 100. *120* was my impossible bar.
     
  15. Topspin Shot

    Topspin Shot Legend

    Joined:
    Jul 24, 2009
    Messages:
    5,013
    You did? Okay, that sounds better. Some rec guys can bang 120 flat, but they're probably 5.0 or higher. And their 120 is nothing compared to the 120 topslice of a pro.
     
  16. Sid_Vicious

    Sid_Vicious G.O.A.T.

    Joined:
    Dec 21, 2010
    Messages:
    11,683
    Location:
    In The City
    I'm a believer in it and after using this app on about 50 professional and amateur videos of guys like Federer, Sam Groth, Roddick, Raonic, Nadal, Janowicz, Wawrinka serving, I have lost pretty much all of my skepticism. Why on earth would I call this method "seriously flawed" when the speed the app calculates is the same or 1-2 kph off the speed that shows up in huge bold letters on the radar gun placed right behind the professional who is serving? Its not perfect for sure, but "seriously flawed" it is not.

    Oh and btw, even in pro tennis they don't bother to report the speed of that serve lost to air resistance. When you see Federer or Nadal strike a serve, the reading shows on the radar at the moment of impact. The viewers have no idea what the speed of the serve was at the bounce and the only way we could is if the commentators use the hawkeye system to give us detailed numbers.
     
    Last edited: Apr 5, 2014
  17. Nickzor

    Nickzor Semi-Pro

    Joined:
    Jan 22, 2013
    Messages:
    472
    Location:
    Melbourne, Australia
    This pretty much sums up my thoughts, as i always said though the method isn't 100% accurate but its good enough for us rec players who'll never be able to afford an ATP level radar gun nor be able to step onto a professional court with a radar gun
     
  18. Dimcorner

    Dimcorner Professional

    Joined:
    Oct 12, 2012
    Messages:
    814
    Ok so I did a semi test. (same post as the other thread but I did promise that I would video on this one)
    No warmup, in a hurry cuz I had baby with me. Also a big one, I was serving with my glasses. I NEVER play with glasses so everything looked VERY weird.

    55 frames from impact to hitting ground. 120fps camera. Calculating from website it shows 105.3 initial speed. 2nd Serve slice was 78 frames for 74.3 mph.

    http://youtu.be/Wu_5ubU5TKM
     
  19. Fintft

    Fintft Hall of Fame

    Joined:
    Sep 28, 2007
    Messages:
    2,655
    Based on your technique and that slow motion videos I'd say, yes, it seems like it.
     
  20. WildVolley

    WildVolley Legend

    Joined:
    Jun 22, 2007
    Messages:
    5,687
    What you've left off is an estimate of distance from contact point to ground impact. Remember that the model is very sensitive to changes in distance.

    That didn't look like it hit the corner to me (it isn't clear on video, so you can tell me if my estimates are way off). If I make a few assumptions (That ball was hit about 8.5 feet in the air about 5' from center, you were about 1 foot inside the court at contact, and the ball landed a foot short of the line) then I get a distance of about 59' in the air which has a speed of about 103mph.
     
  21. Dimcorner

    Dimcorner Professional

    Joined:
    Oct 12, 2012
    Messages:
    814
    Ok 103 mph. Either way it's 100+ mph for a 3.0/3.5 player. On match situations I think I'm closer to 90-95 mph first serve and about 70-75 second serves. If I really try I think i can crack between 110-115.

    Anyways this is high speed video proof that amateurs CAN hit 100+. I bet with more practice I can hit just at 100mph for matches with +50% good serve rate.
    Also as a note. I have been playing tennis for just under 2 years. I'm 38 this year and i'm 5'7" 148lbs. So technique matters a lot. You don't need to be tall but I bet it would sure help.
     
    Last edited: Apr 13, 2014
  22. WildVolley

    WildVolley Legend

    Joined:
    Jun 22, 2007
    Messages:
    5,687
    I believe you can hit over 100mph. I was one of the original people in this thread arguing that it isn't an unreasonably high standard. I've been trying to get people in this thread to estimate distance because the frame count model is very dependent upon distance. Having a camera angle that shows court impact is crucial to getting a reasonably accurate estimate.

    It does help to be taller. Having a higher contact point makes it much easier to hit down into the court. Of course, taller guys need to be careful about over-estimating speed because if they hit a ball in four or five feet in front of the service box line, the frame count will be very low and the distance much shorter. If they assume 60' in the air, the frame count method will read substantially high compared to a radar measurement.

    Really tall guys like Isner can force errors by hitting a ball down short into the box, and because the path to court contact is so short, the ball retains more speed prior to the bounce than harder deeper serves hit by shorter players.
     
  23. LeeD

    LeeD Bionic Poster

    Joined:
    Dec 28, 2008
    Messages:
    35,688
    Taller gives you better leverage and also a bigger target court to hit into. 2 huge advantages.
    Very few good players shorter than 6' tall regularly employ flat first serves.
    Video count is a nice tool for the virtual world.
    And yes, mostly, shorter players seem to have much lower bounce on equal speed serves, unless the courts are brand new or super abrasive.
     
  24. shindemac

    shindemac Hall of Fame

    Joined:
    Aug 2, 2005
    Messages:
    2,210
    Your movement and recovery look good in that vid.
     
  25. anubis

    anubis Hall of Fame

    Joined:
    Mar 2, 2012
    Messages:
    3,009
    Am I the only one in this thread that thinks fast serves aren't necessary to be successful in rec tennis? I'm plenty successful (and happy) with my 50-60 mph serve. I can serve to someone's forehand, backhand or body easily, so IMO that makes the serve more usable and practical than a 100 mph serve that you can't control.

    and If I'm just way off base, and most of you guys who can hit 100+ mph serves and still direct it to a forehand or backhand at will, then you don't belong in rec tennis -- you belong in open level tournaments.
     
  26. WildVolley

    WildVolley Legend

    Joined:
    Jun 22, 2007
    Messages:
    5,687
    Of course, big serves aren't necessary, but if you can hit 95-105 mph why hit 50-60?

    It isn't different than for other strokes in rec tennis. Some guys hit very softly, and other players enjoy hammering the ball. Even the guys who can hit hard don't only hit hard.

    Who is "most of you guys?" There is some tradeoff between pace and control, but it isn't a linear relationship.

    Again, good servers aren't necessarily open players. Hitting a good serve doesn't necessarily mean ability to control ground strokes, or great movement, or fitness, or the ability to volley, etc.

    People get angry at those who say "I have a 4.5 serve but a 3.0 backhand." While they are correct in that NTRP levels aren't determined that way, those making that distinction are attempting to discuss strengths and weaknesses.
     
    Last edited: Apr 18, 2014
  27. psv255

    psv255 Professional

    Joined:
    Aug 31, 2011
    Messages:
    956
    Location:
    NY
    This thread started out having nothing to do w/ being successful in tennis, the OP was saying that some posters were underestimating serve speeds. It's a hack thread for hacks who are showing other hacks that there some hacks who can serve relatively fast, and that more concrete estimating methods than the eyeball are indeed somewhat reliable. Doesn't mean theyre successful in rec tennis.
     
  28. Maximagq

    Maximagq Banned

    Joined:
    Sep 17, 2013
    Messages:
    6,555
    Is Open Level tennis considered rec tennis?
     
  29. Cobaine

    Cobaine Rookie

    Joined:
    Sep 26, 2005
    Messages:
    284
    Location:
    San Luis Obispo, CA
    In the real world: Anyone whose income is not derived from playing tennis a rec player.

    In LeeD bizarro world: who knows?
     
  30. LeeD

    LeeD Bionic Poster

    Joined:
    Dec 28, 2008
    Messages:
    35,688
    Rec players CAN hit 130 mph serves......
    A/Open is mostly recreational tennis, although some guys better than TonLars are trying to make the pro scene and are close to covering expenses.
     
  31. BounceHitBounceHit

    BounceHitBounceHit Legend

    Joined:
    Jan 17, 2005
    Messages:
    5,939
    Location:
    In the moment.
    I am amused more has not been written about the serve GAME and return GAME. The serve and return are the two most important shots in tennis, in that order (IMO). HOWEVER, they simply START the point in all but a VERY few truly exceptional players (who are almost exclusively professional, in the sense they earn their living on the ATP or WTA). It's not just the speed, spin, or placement of the serve (all important, for sure!) but what you do with the ball you then receive in return. Same when returning. The return can 'set up' the NEXT shot, which then puts the returner on the OFFENSIVE, even if a clear ace/winner is not struck. Considering just how unusual aces/return winners really are at ANY LEVEL (and they are VERY, VERY rare as you play better and better players, who can both react both quickly and decisively be it to the serve or the product of an aggressive return) this seems far more important to me than either shot 'in isolation'. :) Just my two cents worth! :) ;) BHBH
     
  32. RoddickAce

    RoddickAce Hall of Fame

    Joined:
    Jul 2, 2007
    Messages:
    2,461
    I agree with Wildvolley and PSV. Also, it is not hard to direct a 100mph serve to someone's forehand, backhand or body. The hard part is maintaining a high % of serves in. And also, the 100mph may be limited to certain areas on the service box depending on what the server favours.

    For example, on the deuce court I know I can hit 100mph+ mph flat serves up the T fairly consistently. But I cannot hit flat serves out wide at the same pace and consistency, although I can control the direction of the serve easily to the forehand side.

    But I'm sure most of the people that can hit 100mph serves can hit 80-90mph topspin/slice serves with a decent % in with even better direction control due to the spin.
     
  33. RoddickAce

    RoddickAce Hall of Fame

    Joined:
    Jul 2, 2007
    Messages:
    2,461

    Yes I agree, but certain posters believe that if you can hit flat serves at the speed of a pro's slightly fast 2nd serve at <50% of their consistency, then it must mean you are pro while completely ignoring every single other aspect of the serve technique as well as all other aspects of playing tennis.
     
  34. shindemac

    shindemac Hall of Fame

    Joined:
    Aug 2, 2005
    Messages:
    2,210
    There's a lot of misconception about fast serves. I'm guessing these statements are coming from really low level players. (100 mph is impossible for recs, 100 mph serve == 5.0 player) We have enough proof that there are 3.5 up to 5.0 that meet this criteria (100mph serve). Technically, i'm sure you can go up to 7.0 and find serves like that. I'm not sure why the statements are so binary, but there's so much variation in the rest of your game and plus there's big variations in the serve. Discounting pace, you got spin, placement, consistency, strategy, etc. That's why tennis is so interesting, and each player is different.

    For example, for hacks lower than me, i have so many different weapons to ensure a victory. Go for aces in the corners, aim for backhand, hard serve, or super spinny and slow slice. For better players, i have to hit as hard as i can while aiming for my spots and keeping my percentage up. Definitely harder, and dropping my serve once means i could lose the set. For others, they would use the same serve to start the point, and rely on the rest of their game.
     
  35. 5263

    5263 G.O.A.T.

    Joined:
    Mar 31, 2008
    Messages:
    10,390
    Really good post and highlights my point about how when you play a far better player, you don't really see his best game, as he will take some liberties due to your lack. He will do what he likes or wants to do, and not be forced with staying with what he CAN do while under pressure of an equal player.
     
  36. sureshs

    sureshs Bionic Poster

    Joined:
    Oct 1, 2005
    Messages:
    34,691
    Is there even ONE video of a rec player hitting a 130 mph serve?
     
  37. LeeD

    LeeD Bionic Poster

    Joined:
    Dec 28, 2008
    Messages:
    35,688
    Sure, that lefty from UCLA, who went pro after his freshman year.
    Suresh, don't be talking serves.
    I can bounce a ball about a foot high off the backwall, an IN serve, with my right hand.
    To me, my right hand plays at the 3.5 level.
    That's painted cement courts, 10 in the morning, 58 degrees, and never with decent bouncing balls.
    YOU sir, have no serve whatsoever.
     
  38. tennis_ocd

    tennis_ocd Hall of Fame

    Joined:
    Aug 17, 2011
    Messages:
    2,002
    Apparently thousands. You count frames and measure distances to get an average speed. Then comes the real magic. Throw in a speed loss due to air resistance number (scientifically based on a Sampras serve because this is the closest the community could find to a true ttw rec player) and, voila, you have initial, rec player off the racket speeds equal to the ATP best. It's proof.
     
  39. 5263

    5263 G.O.A.T.

    Joined:
    Mar 31, 2008
    Messages:
    10,390
    I guess you are joking, but the frame count is already adjusted to account for speed lost over distance or either its useless.
     
  40. sureshs

    sureshs Bionic Poster

    Joined:
    Oct 1, 2005
    Messages:
    34,691
    So there is not even ONE video of a rec player serving at 130 mph.
     
  41. WildVolley

    WildVolley Legend

    Joined:
    Jun 22, 2007
    Messages:
    5,687
    ocd is just really angry that a bunch of hack amateurs can hit over 100mph. And he constantly shifts the goal post. People post serves over 100 mph and to him that's equivalent to claiming they hit 130mph.:confused:

    I'm sure that there are a few rec players who can serve over 130mph, but I think we all agree that's extremely rare. I've never seen it, but I've hit close enough to 120-125mph in the past to know that it is definitely in the realm of possibility.
     
  42. mightyrick

    mightyrick Hall of Fame

    Joined:
    Aug 19, 2010
    Messages:
    4,611
    Location:
    Austin, TX
    I also think people started talking about different things... which caused a lot of confusion. Here are the different things I saw bandied about:

    1. Ability to hit a single first serve over 100mph (in or out)
    2. Ability to have an avg. first serve speed over 100mph with a low "in" percentage (<50%)
    3. Ability to have an avg. first serve speed over 100mph with a high "in" percentage (>50%)

    Those are all very different things. I think the #1 and #2 are the only ones that a recreational player could do. But quite honestly, the first two items basically mean you have a fast, crappy first serve. I'd argue that the last one means you are basically a professional.
     
  43. WildVolley

    WildVolley Legend

    Joined:
    Jun 22, 2007
    Messages:
    5,687
    The initial discussion was about point #2: The ability to hit a 100mph serve in, though the % wasn't being discussed.

    I agree that if the serve doesn't go in, it really doesn't count. That's a problem with the serve cages, but they do show ability to generate enough racket head speed.

    The data collection required to prove point #3 is much greater, especially if we look at sets over time. I think it would be easy for a number of the people in this thread to get video of a single game in which they average first serves over 100mph. When it comes to people who can consistently do that, the number greatly thins out. But there are tall amateurs who don't have great serves who can probably average over 100mph just by hitting hard flat serves at the center of the box. That's not a very ideal serving strategy.
     
  44. Ballinbob

    Ballinbob Hall of Fame

    Joined:
    Sep 7, 2008
    Messages:
    3,323
    Location:
    colorado
    There are many, many people I know who can hit over 100mph and make 50% of them. I can do that too a lot of the times, and I'm a 4.0. Not very hard if you are athletic and have a live arm. As I said earlier in this thread, my friend who plays DI baseball in Virginia was hitting 110-120 mph EASY and he does not play tennis. He was literally just tossing it up and swinging.He is 6'7 though.

    I'm playing tonight against a fellow 4.0. I will record the whole session and see what my first serve % is. I'll be going for flat serves the entire set

    EDIT: My friend is actually 6'9, my bad. Here is his baseball profile for those interested....http://www.virginiasports.com/sports/m-basebl/mtt/brett_lisle_795479.html
     
    Last edited: Apr 18, 2014
  45. sureshs

    sureshs Bionic Poster

    Joined:
    Oct 1, 2005
    Messages:
    34,691
    Yeah a 6'9" D1 athlete is what we typically mean by a rec player
     
  46. WildVolley

    WildVolley Legend

    Joined:
    Jun 22, 2007
    Messages:
    5,687
    It will be interesting to see clips from that if you get good video.

    Here's an example of how tall guys have it easier, though admittedly this guy is an ex-college player and doesn't fit our rec criteria.

    http://www.youtube.com/watch?v=LPzcq5GS9x8

    You hit a decent serve even with what I still consider to be some big technical issues.
     
  47. WildVolley

    WildVolley Legend

    Joined:
    Jun 22, 2007
    Messages:
    5,687
    The guy isn't the best example, but a number of typical players have posted video evidence on this very thread.

    I competed in college sports (track & field) but was never on scholarship nor at a Div 1 school. I'm still a rec player, and used to be able to easily hit over 100 mph. At the time I was doing it, I considered myself a 4.0 player, though that was completely a self-rating as I wasn't playing tournaments and based my rating on playing against computer rated people in non-tournament settings.
     
  48. Ballinbob

    Ballinbob Hall of Fame

    Joined:
    Sep 7, 2008
    Messages:
    3,323
    Location:
    colorado
    He does not play tennis though ! Like at all. He is a rec player in tennis, what else would you call him? A professional? I'll see him this summer when he's back from Virginia and I'll film his serve. It's sick

    That's my point exactly. I have a lot of technical issues with my serve but I can still get it in over 100mph no problem. I'm not the only one who can do this. And I will get a good angle today, I have a good wide-angle lens for my iphone and the videos always turn out really nice. I'll post back tonight. Hopefully I'll serve well today lol
     
  49. ctoth666

    ctoth666 Professional

    Joined:
    Sep 9, 2010
    Messages:
    827
    Location:
    Woodstock, CT
    That court has some hops. How tall is that guy?


    I would have to believe that my flat serve reaches measurable speeds of 110 mph or higher. I would be surprised if it didn't, however I haven't used a radar gun since I was a lad. Maybe I'll do a serve video. When I hit a spot on my serve, which is not all that frequent, it's fast enough that the other guy can't really react to it. And if I go body, I've hit people a number of times. I've popped a ball before. So that is my guess.
     
  50. shindemac

    shindemac Hall of Fame

    Joined:
    Aug 2, 2005
    Messages:
    2,210
    Yea, where did this new 130 come from?
     

Share This Page