Why do pro's hit the ball at the top of the racket

Discussion in 'General Pro Player Discussion' started by ace high, Mar 28, 2010.

  1. ace high

    ace high Rookie

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    Looking at FYB2007 BNP Paribas slow mo videos all the pro's seem to be hitting the ball at the top of the racket.
     
    #1
  2. Commando Tennis Shorts

    Commando Tennis Shorts Hall of Fame

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    It seems to me that's where the sweet spot would be for a lot of pros' racquets, considering the lead/weight distribution/heft.
     
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  3. Gimmick

    Gimmick Semi-Pro

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    The highest racquet speed is at the top.
     
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  4. kishnabe

    kishnabe G.O.A.T.

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    They hit at the top of the racquet since the ball would roll down to the centre...the purpose is for the ball to have top spin. Since this era is mostly about Top Spin(RPM)...Federer and Nadal dominant in creating top spin. By hitting at the top of the racquet the ball at the end will leave of the centre which is the sweet spot. Easily create top spin and hitting the sweet spot. If you don't believe there are commentators who have talked about this...also Gasquet Backhand is a clear example of this and so is Federer forehand!
     
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  5. DRII

    DRII Legend

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    Spot on...

    the basic physics of centrifugal force!
     
    #5
  6. slicefox

    slicefox Banned

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    ROFL

    as somebody who studies mechanics, you are an awful noob.

    1. There is no such thing as "centrifugal force".
    2. "centrifugal force" has nothing to do with hitting a ball.
    3. you are a noob
     
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  7. mzzmuaa

    mzzmuaa Semi-Pro

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    ya nooob
    it's not centrifugal force it's electromagnetic induction
     
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  8. OKUSA

    OKUSA Hall of Fame

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    it's nuclear fusion
     
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  9. Emperor

    Emperor New User

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    this is the dumbest post i have ever seen
     
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  10. jwbarrientos

    jwbarrientos Hall of Fame

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    I heard is sth related with dark force
     
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  11. kishnabe

    kishnabe G.O.A.T.

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    Um...Isn't that have to do with rotating and object on a wire or when car is doing a banked turn....Please go and learn some Gr.12 Physics!
     
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  12. OKUSA

    OKUSA Hall of Fame

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    i think tennis people should stick to tennis, and scientists stick to science
     
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  13. _maxi

    _maxi Banned

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    The larger the distance from the rotating point, the bigger the momentum you get.
     
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  14. AllDownTheLine

    AllDownTheLine Rookie

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    Um... Doesn't that have to do with rotating an object on a wire or .......Please go and learn some GR. 6 English!

    BTW, I graded your post......FAIL!
     
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  15. shermanator12290

    shermanator12290 Rookie

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    this is the dumbest post i have ever seen
     
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  16. bluetrain4

    bluetrain4 Legend

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    I think most people who are decent players hit the ball between the top of the frame and the middle of the stringbed, thus, higher in the stringbed than the midpoint.

    I don't find it unusual at all. And most racquets have a sweetspot higher than the midpoint.
     
    #16
  17. pyrokid

    pyrokid Hall of Fame

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    This is the dumbest post I have ever seen.
     
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  18. LameTennisPlayer

    LameTennisPlayer Professional

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    ^^^^
    man i have sextuple vision and i haven't even started drinking yet
     
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  19. shermanator12290

    shermanator12290 Rookie

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    lol yea i was actually thinking that after i posted that.. it could go on forever.. nice one.. although you finished it sooo..
     
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  20. Nextman916

    Nextman916 Professional

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    This is turning into the dumbest thread ive ever seen.
     
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  21. DRII

    DRII Legend

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    Some of the comments are ridiculous!

    There is a clear relationship between centrifugal force and any rotational movement, including the swing of a tennis racquet, and its effect on the power and pace a tennis ball comes off the racquet.

    Essentially; the greater the distance between the center of rotation and the contact point (holding all other variables equal) the greater the momentum and degree of rotation, which results in more power, pace, and spin.

    This is why you are supposed to swing from your hips and not just the shoulder or elbow or wrist. This is also why the higher (really the longer) the ball contacts the racquet head string-bed the greater the power, pace, and spin.

    This is why most pros hit the ball along the furthest point up on the racquet head. Notice when a string breaks, it is usually on the top part of the racquet head.

    Its called physics. Although its not a literal translation of the concepts (centrifugal and centripetal forces), only because hardly any person is capable of a full 360 degree rotation on a stroke, the fundamental idea holds true.

    Live and learn!
     
    Last edited: Mar 28, 2010
    #21
  22. mark999

    mark999 Rookie

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    actually you mean dark matter, not dark force.
     
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  23. LDVTennis

    LDVTennis Professional

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    No, it's not physics...

    There is no basic physics of centrifugal force because as far as classical mechanics is concerned it is a "fictitious" force. In short, classical mechanics demonstrated that the circle drawn by this "fictitious" force is actually composed of two linear forces, acting opposite to each other. That is why slicefox was right in saying that there is no such thing as centrifugal force.

    As to the rest, it may sound rational to you, but given that it is all premised on the faith you have placed on a "fictitious force" how can it be? What did slicefox call you again?

    As to the question the OP asked, I found this article a while back: http://polaris.deas.harvard.edu/galileo/images/material/852/151/AmJPhys_tennis_3.pdf. Sections V and VI of this article give a partial answer.
     
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  24. ace high

    ace high Rookie

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    How would you get the ball to roll down the racket?
     
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  25. gzhpcu

    gzhpcu Professional

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    A racket that is rotating around a fixed axis has angular momentum. All points of the racket have the same angular speed.

    To calculate the angular momentum (AM) of the racket,
    AM = m(r1^2+r2^2+r100^2)omega.
    whereby m=mass of racket, and m1 thru m100 are the radii of segments of the racket divided into 100 pieces. (more accurate would be to use an integral function and integrate from zero to the r of the tip of the racket).

    source: "The physics and technology of tennis", Howard Brody, Rod Cross and Crawford Lindsey

    Omega is the rotational speed in radians/second.


    Speed of the ball after impact is given by the formula:

    v = (1 + e)V, where v=velocity of ball, V=velocity of racket, e=ACOR

    ACOR = apparent coefficient of restitution

    The ACOR is determined by holding the racket by hand at rest and firing a ball at right angle to it. If the speed of the ball prior to impact is v(1), and the speed of the ball after impact is v(2), then ACOR=e=v(2)/v(1).

    The serve speed is 8% higher when you hit from the middle of the strings than when serving from the top.

    Top players tend to serve from near the top because the added height advantage reduces the chance of serving a fault. However, they usually customize their rackets by adding lead at the tip, which increase "e" in that region.
     
    #25
  26. DRII

    DRII Legend

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    I don't know why you and slicefox refuse to remove yourself from the realm of classical mechanics when it comes to discussing the physics of tennis.

    Centrifugal force is a term and concept commonly used in sports science. You two can naively choose to artificially limit yourselves, but don't expect me to do the same...
     
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  27. heretoserve

    heretoserve Rookie

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    OP. Do you mean the top as closer to the side/frame at contact. One poster did hit it. The ball will stay on the strings for a few inches. The best hits start above the middle and roll to the middle before they leave. The ones we see on youtube though are where they hit the middle roll to the bottom and cause the racquet to turn over(what every body wants to see and tries to emulate by flipping your forearm and wrist at contact).

    Other wise you actually get more power closer to the throat, as the racquet has more resiliency there. Despite that the end of the racquet is moving faster.
     
    #27
  28. Kostas

    Kostas Semi-Pro

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    lol @ this thread....
     
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  29. LDVTennis

    LDVTennis Professional

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    Remove ourselves from the realm of classical mechanics? Well that confirms all your foolishness.

    As to sports science, you will do us the favor of pointing out where in the article I referenced earlier the author H. Brody uses the concept of centrifugal force to explain the ball-racket interaction. I don't remember him mentioning it once, but then I wouldn't want to artificially limit myself. After all, who needs classical mechanics to explain the interaction between two bodies at velocities well below the speed of light.
     
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  30. DRII

    DRII Legend

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    Look it up, if you need further explanation!

    Again, the concept of centrifugal force is commonly used in sport science. If you don't know you better ask somebody...

    And FYI, 'classical mechanics' as theory has been revised, reformed, and refined many times and continues to be...

    If you are so foolish to adhere yourself to a literal definition of centrifugal force as to essentially say it does not exist then you are most certainly limiting yourself!
     
    #30
  31. drakulie

    drakulie Talk Tennis Guru

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    From the high speed video I have recorded, pros are mostly hitting around the center of the string bed.
     
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  32. gzhpcu

    gzhpcu Professional

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    Centrifugal force is experienced during rotational motion, by an object tending to continue in a straight line instead of a curved path.

    As such, it is not relevant to the impact of the racket and the ball.
     
    #32
  33. sjam316

    sjam316 Rookie

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    yeah...too bad there's no such thing as "centrifugal force"
     
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  34. ProgressoR

    ProgressoR Hall of Fame

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    I work for NASA. I make space ships. If it wasn't for people like me we would still be playing tennis with rocks and clubs. I say the correct answer on the dispute over centrifugal force is that the further along the limb and racket you go the faster the speed of travel. Thus the fastest point is the very top tip of the frame. I am experimenting with having a mini head and strings attached the top of a conventional racket and aiming to hit the ball with this mini face. The results are startling. I can say no more at this stage. But look out in your local sports store shortly. You should burn this post now. Or delete the thread. I might have said too much already. Disregard what I said about nasa. But still keep an eye out ...
     
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  35. kOaMaster

    kOaMaster Hall of Fame

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    lol. what a thread. and too many people talking about something they don't have a clue but act as they do.

    oops, I just did the same...
     
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  36. David L

    David L Hall of Fame

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    They don't. At least, that's not their intention. The goal is to make contact with the sweet spot in the centre of the racket, which provides the best transfer of power. If they are making contact near the top of racket, then it's unintentional, unless they happened to be testing a racket to see its different responses. Any contact made near the top of the racket is going to be poor in comparison to the sweet spot in the centre.
     
    #36
  37. shanked_it

    shanked_it Rookie

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    Lol, someone didn't understand his newtons :oops:
     
    #37
  38. LDVTennis

    LDVTennis Professional

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    The consensus in this thread is that you don't know what you are talking about. Argument over. You FAIL.
     
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  39. DRII

    DRII Legend

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    The consensus of you and some of your naive brethren makes little difference to me...

    Due to centrifugal force the furthest point of the racket head travels the fastest (during the stroke or swing) and thus produces more power and spin at contact...

    Simple as that.

    I know you always seem to look for an argument, but there is no need for one, I won't give you the satisfaction.
     
    Last edited: Mar 29, 2010
    #39
  40. DRII

    DRII Legend

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    Sweet spots differ depending on the racquet and its balance (its not always in the center).

    But holding everything else equal you will achieve more power hitting along the furthest point on the racquet head while still maintaining full contact with the strings...
     
    #40
  41. DRII

    DRII Legend

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    Oh thats cute :???: ...

    I'm sure you and your mates have experimented with various forces of rotational phenomena during your many road trips with youtube clips to show for it.
     
    #41
  42. kOaMaster

    kOaMaster Hall of Fame

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    lol. hey, at least you watched it. but yeah, as you can imagine, there's something in between vacation and building tools for fun ;)
     
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  43. David L

    David L Hall of Fame

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    Yes, but everything is not equal. The string tension is more taut the closer you get to the frame, thereby reducing the amount of power you can generate. The lowest tension is found somewhere in the centre, which means more power. It's exactly the same with a trampoline. The closer to the edges you get, the less spring you get. The extremely negligible difference in speed a couple of inches from the centre cannot and does not make up for this in human hands. Also bear in mind that the direction of a tennis stroke is not completely rotational around a tight 360 degree axis like earth. Much of the stroke is linear up to the point of contact and only experiences a sharp change in direction as you follow-through and after the ball has left the racket.

    What you are describing would make more sense with games like jai alai or Basque pelota, which do not depend on propulsion from a trampoline type string bed.
     
    Last edited: Mar 30, 2010
    #43
  44. Wes_Loves_Dunlop

    Wes_Loves_Dunlop Professional

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    The reason pros hit at the top of their rackets is because you get the most racket head speed there.
    The sweetspots are not that high up on the string beds, but by hitting slightly above the sweet spot, you hit a stiffer area of the string bed which would result in more spin. Also, because the tip is the fastest, you still get enough power.
     
    #44
  45. shanked_it

    shanked_it Rookie

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    You know, the problem isn't really that you don't quite understand, it's that you say these things like facts, and then go on to call other people naive.... That's the problem here.

    And yes, the racquet head speed is the fastest at the tip. You are talking sense, but you have not understood that physics is just a model for humans to understand natural phenomena better, it is not fact in itself. It's just that it has been built on theories, and then just jumping out of some theories and taking others, and making some up in between breaks the model.
    I do understand that you are just trying to talk about it in laymans terms, and simple things like this one are perfectly understandable like this, but as things get complicated breaking the models which help us understand (these models are not the reason for reaction, they are there only to help us understand) will make it all a big mess, especially for us naive people.


    On topic, I'm guessing it's the weight distribution most pros go for, to help them use optimal leverage to drive through the ball...

    As someone stated, the longer the lever, the higher the acceleration, the higher the force with the same mass. Acceleration could be gotten through having many levers/axis aswell, instead of just one rotating lever. Thinking in components, remember that courtside movement, and spin, are opposite to eachother, and one only has so many levers, so you have to go for one or the other with each lever...
     
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  46. Jakesteroni

    Jakesteroni Rookie

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    Theres an article in the USTA mag that explains how to hit a kick serve, it shows Stosur hitting a kick serve. Look it up. It might clear some things up.

    Correct me if I'm wrong, if someone does hit at the top of the racket doesn't that mean the racket is constructed to have a sweet spot there? Same concept as customizing a racket, by you putting lead at 12 you move the sweetspot higher. As for breaking strings and wear pattern my strings break usually just slightly higher than 3 and 9 o clock but not so much 10 or 2. So, for the OP I'm guessing its just how your frame is balanced.
     
    #46
  47. Wes_Loves_Dunlop

    Wes_Loves_Dunlop Professional

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    Lead wont move the sweetspot 2 inches on the string bed.
    Moving the sweet spot is meant for tiny adjustments. Not inches
     
    #47
  48. DRII

    DRII Legend

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    I agree with everything you have said here, and basically said the same thing in a different way (if you look at my responses you will see this).

    Mainly I am responding to the person I quoted and a few others who try to debase my original response with ridiculous or needlessly ugly assertions. Those were the ones I was calling naive, not you or others who are clearly rationale but may still disagree.

    Sorry for any misunderstanding…
     
    #48

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