Top spin production in ground strokes -- namely calling for Ash

Discussion in 'Tennis Tips/Instruction' started by 10isfreak, Aug 1, 2013.

  1. 10isfreak

    10isfreak Semi-Pro

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    As I stated times a many, I subscribe to the group who considers that the angle of your string bed at contact is the main factor influencing the production of spin in ground strokes. I got this from tennisspeed, if you want my source. I might break down my thought process later on, but it's not my main intention here... I want to know about people on this forum since one blog is too limited as a source of information and I might actually be very wrong.

    I called for you Ash, if happen to stop by, because I wished you had some space to reply to me or to explain your position. You are well known here for your great inputs and good manners, so while we might all enjoy your insights, you wouldn't highjack another thread to explain... hence this space.


    For everyone, the question is:What produces top spin in forehand and backhand ground strokes?
     
    Last edited: Aug 1, 2013
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  2. sureshs

    sureshs Bionic Poster

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    I will respond since some people call me SurAsh.

    So I assume this is about the contribution of racket face angle versus swing path.

    High speed video shows that pros like Federer have their racket face perpendicular to the ground or slightly closed at contact, and they seem to maintain this from before to after contact. This supports the idea of the swing path being the main contributor to spin, and racket face angle determining the launch angle and hence depth.

    However, even a slightly closed face can have big consequences at high swing speeds, and I have seen other pros who seem to rely on some wrist movement also for adding spin, pointing to the importance of racket face angle. I also think a more closed face can create more top spin and bring the ball down faster, and I think this is because of an increase in dwell time.

    So yeah curious to know how this is resolved.
     
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  3. newpball

    newpball Legend

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    Could you provide a link because I could not find anything that confirms what you claim.
     
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  4. 10isfreak

    10isfreak Semi-Pro

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    Suresh and newpball, this is the article which convinced me:
    http://blog.tennisspeed.com/2011/05/roadmap-to-hall-of-fame-forehand-part-1.html

    The string bed is systematically closed beyond the vertical plane, mostly between 10 and 20 degrees, and the swing path prior contact is always pretty shallow -- in the example he gave, Federer and Nadal both swung at 18 degrees from the horizontal plane.

    As for the angle of the racket face, it opens up (becomes less closed, actually) as you swing forward -- the best pros start with their racket face parallel to the ground.
     
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  5. Tight Lines

    Tight Lines Professional

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    I don't understand this question. What creates top spin is a complex interplay among the racket angle, swing path and speed of the swing. You can't just isolate one factor. They are all related.

    Harry
     
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  6. TimeSpiral

    TimeSpiral Professional

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    When talking about topspin, the angle of the string bed is incidental--influencing the swing path.
     
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  7. 5263

    5263 G.O.A.T.

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    I think he means the primary TS influence.

    My take is the power top spins rely more on racket face, whereas
    the roller type topspins are more about vertical swing path with a
    log of leg augmentation.
     
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  8. 10isfreak

    10isfreak Semi-Pro

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    Yes, but given what I wrote, you'd think it's possible to hit a top spin drive with a downward launching angle or a backspin lob by hitting upward.
     
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  9. TimeSpiral

    TimeSpiral Professional

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    That article gets a big *shrug*. Thousands of words correlating some lines on some graphics to the production of topspin. I know you took away a lot from that article, so this might seem flippant, but it truly is a lot about nothing.

    Putting topspin on a tennis ball is super easy, and an even easier concept. Use the racquet to spin the ball about it's X axis. Simple as that. However you can, or want to produce that effect, is fine, as long as you're happy with the result.

    He could have shrunk that article down to this and accomplished the same thing: practice tennis for 8 hours a day and you're on your way to hitting topspin like a pro! Sounds flippant, again, but I'm serious. Even the most detailed understanding of rotational physics will increase your potential tennis skill by a mere fraction of what more practice would do.

    I like to know technique as much as anyone here, don't get me wrong, but you're way over-thinking this one.
     
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  10. newpball

    newpball Legend

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    Read the article, I think it is doomed to confuse more than to clarify anything.

    Also what happens before and after impact is completely irrelevant. A player can make seven full somersaults after impact but it would not do anything.
     
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  11. Ash_Smith

    Ash_Smith Hall of Fame

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    My understanding of the relationship between path angle and speed comes from a biomechanist and coach I worked with for many years from France who worked for the FFT and ATP and also from my own empirical evidence from years of working with players on court. Essentially for the same swing path (assuming the same contact point on the ball) a more closed face will create a lower launch angle than a vertical racquet face.

    Obviously as Tight Lines says, all three variables are inter linked, but in my experience racquet face determines launch angle and path determines spin (that is to say has a greater bearing over).


    Here comes the (not very) science bit..!

    If a ball hit with heavy topspin hits your racquet which is stationary and in a vertical (neutral) position the ball will leave the racquet above the angle of incidence due to the spin. If you hit said ball with a low to high path bit maintained the racquet face as neutral you would impart counter spin, but the launch angle is still higher. Repeat with a closed racquet angle and the launch angle is lower.

    As for tennispeed - happy that he has "proven" that the pro's have a closed face at contact. Not convinced he has proven that this factor is the major contributor for topspin production, at least above racquet path.

    cheers
     
    Last edited: Aug 1, 2013
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  12. TimeSpiral

    TimeSpiral Professional

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    When getting into the weeds of this--which I think is unnecessary in the context of playing better topspin tennis--it is important to point this out: By maintaining the same swing path, and only changing your racquet face, your are actually changing the part of the ball you're hitting/interacting with.

    And I agree; the tennispeed article is underwhelming to the point of being worthless.
     
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  13. Ash_Smith

    Ash_Smith Hall of Fame

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    From the LTA coach education resource...

    Ball Characteristic: Height

    • Path:
    A more level path will keep the ball on the same height. A low to high path will send the ball higher. A high to low path will send the ball lower.
    • Angle:
    Opening the racket face angle will send the ball higher. Closing it more will send the ball lower.
    • Speed:
    Increasing the racket speed can also increase the height of a shot if the racket face and path are angled 45 degrees or above. Decreasing the speed lowers the height of the ball.

    Characteristic: Topspin

    The amount of topspin can be increased or decreased by changing:
    • The racket path
    (a more upward path will increase the spin)
    • The racket speed at impact
    (more racket speed, will increase the amount of topspin)

    (Language is simplified (as tennis coaches are a bit simple :D) but is based on research evidence from Cambridge University Cavendish Laboratory and the Institute of Physics)
     
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  14. rkelley

    rkelley Hall of Fame

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    10isfreak, thanks for starting this thread. I was actually thinking about this as well.

    As for the question, I'm in the same camp as Ash. Basically, swing path for topspin, racquet angle for launch angle. There is interaction to be sure, but when I hit I need to keep it as simple as possible. When I want more topspin I try to get a larger component of the swing's velocity to go up and for flatter shots I hit through the ball more. I use the racquet angle to adjust the launch angle, which is what I'm specifically looking at as I hit.

    After that it's up to nature and God as to where the ball lands.
     
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  15. TimeSpiral

    TimeSpiral Professional

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    As the ball is flying through the air, after I strike it, I'm able to will the ball onto the line. For instace: Ball's in the air. I think: line--and so it happens.

    Ball hit the top of the tape, I slow down time--Matrix style--point my hand forward, and simply will it to land on my opponent's court.

    Nature? God? Pfft. Once you're mastered racquet face angle, you gain Neo-like control over the game of tennis. It's awesome.
     
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  16. rkelley

    rkelley Hall of Fame

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    OK. So now I know why I suck.
     
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  17. RetroSpin

    RetroSpin Hall of Fame

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    Nadal hits the vast majority of his FHs off the bottom half of the racquet face, not the center. To me, that is far more interesting than the face angle debate.
     
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  18. bhupaes

    bhupaes Professional

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    I think the angle of the racquet face mainly helps with control. The exact amount should depend on one's intended trajectory and depth, amount of topspin, and amount of pace.
     
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  19. 5263

    5263 G.O.A.T.

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    but they are very related though :)
     
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  20. 5263

    5263 G.O.A.T.

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    Come on Ash you know this is correct :)
     
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  21. tennis_hack

    tennis_hack Banned

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    on the backhand I can control the racket angle much better than on the forehand, as I twist the racket in my hand as I go through the take-back.

    If I twist the racket aggressively I know that the racket face will be closed, and I'll need to swing as fast as I can upwards and forwards just to clear the net and the effect will be a lower trajectory ball, yet still with heavy spin that kicks up around the shoulder-to-head level.

    Incidentally, this is how I've come to learn how you 'flatten out' high balls on the 1hbh - although there is still heavy spin in the shot, just the ball goes lower over the net. (If you want pure flat, a Tommy Haas-type continental backhand is probably better.)

    If I don't have enough time or want to hit a high topspin loop, I will not twist the grip as much as I know this will lead to a more open racket face. I can push the ball like this if I don't have enough time to swing fast, or I can swing fast like this and it will produce a very high and deep topspin loop that apparently is a nightmare to deal with when it bounces.

    In this way I think the sw grip 1hbh is a versatile shot to vary the trajectory of balls.

    Utterly sucks against low balls but you can't have everything.
     
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  22. sureshs

    sureshs Bionic Poster

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    Except the relation has two opposite solutions, both of which have been proposed.

    If the face is more closed, you tend to hit the ball on the lower half.

    Or on the upper half.

    The answer also depends on whether the ball is rising or falling when you hit it.

    Yes there is a relation but what exactly is it?

    There was a guy here who insisted that slice is hit with lower half and top spin with upper half, because that gives margin as the face moves wrt the ball. Miss it slightly, you still have most of the face left. That is quite opposite to what others think.
     
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  23. toly

    toly Hall of Fame

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    First of all, you guys should read Rod Cross article, Physics of the Tennis Kick Serve. See http://twu.tennis-warehouse.com/learning_center/kickserve.php.

    There is citation and picture from the article:

    [​IMG]

    The amount of topspin is shown in Fig. 6 with the symbol S. Experiments and theoretical estimates both indicate that S is given to a good approximation by S = 1.45 VA where S is the spin in rpm, V is the racquet head speed in mph and A is the approach angle in degrees. For example, if A= 0 then S = 0 meaning that there is no spin generated at all. If V = 100 mph and A = 30 degrees then S = 4350 rpm. The amount of spin therefore increases with both the speed of the racquet head and the approach angle of the racquet head. The amount of spin also depends on the speed of the incoming ball, but in a serve, the ball is almost at rest when it is served.
     
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  24. NLBwell

    NLBwell Legend

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    Interesting topic as far as a technical discussion, but of no use in actually hitting a tennis ball.
    Of course, the racket face is closed for a topspin shot - unless you want it to go way up in the air. A racket traveling upward striking a ball coming at it has a frictional force on the ball in the vertical direction. Since it is off-center to the ball, this imparts a rotational torque to the ball. However, the strings also produce an upward force (the collision is somewhat elastic) on the ball. This force must be cancelled out by closing the racket face to get the desired trajectory (again, unless you want a very high shot).
    Hitting in the lower part of the stringed is likely mostly due to attempting to not hit the ball with the top edge of the frame as it passes across the trajectory of the ball. Striking in the lower (earth local vertical) part of the stringed will also lead to a higher launch angle than striking it in the exact center of the stringbed because the strings below the ball will deflect less than the strings above the ball (assuming the racket doesn't twist). Again, this effect would be countered (and the cause magnified) by closing the racket face.

    Of course this is all useless unless you can decide ahead of time whether you will strike the ball at 16 or 19 degrees and whether you will hit 1/2" or 5/8" below the centerline of the stringbed. If you can't do that, then it is a matter of just practice to train your body to get the desired effect.

    People often don't think about what is a cause and what is an effect.
     
    Last edited: Aug 1, 2013
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  25. Tight Lines

    Tight Lines Professional

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    Hi Ash,

    I am not sure if you have read through the entire blog, but I read that thing several times very carefully. To me, the key takeaway is in Part 6 of the blog.

    http://blog.tennisspeed.com/2012/05/roadmap-to-hall-of-fame-forehand-part-6.html

    It's not the closed racket face itself, but what gets you to close the racket face consistently and with control that is important. According to Dr. Nii, the key to producing a consistent closed racket face top spin forehand is "elbow pronation" during what he calls a first forward move. I think the phrase elbow pronation is confusing. I would prefer closed racket face during the moment when you switch from back swing to forward swing. That is key.

    IMHO, for those who think the blog makes no sense, they have not read it very carefully. He makes a ton of sense to me and it has helped my forehand.

    Harry
     
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  26. 10isfreak

    10isfreak Semi-Pro

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    Actually, it's pretty clear. You can't have it clearer, it's the exact word you need to say ''turn your palm face down.'' It's only a problem if you don't know what it means, but being an actual word, you can solve this by looking it up.

    I must agree... you just need to learn some new vocabulary and voila! He breaks down the forehands of Federer, Nadal and Djokovic into 40 or so distinct movements... can't get it clearer and more nuanced than this! :lol:

    Ces articles ne sont quant même pas rédigés en français; c'est bel et bien écrit dans votre langue!
     
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  27. sureshs

    sureshs Bionic Poster

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    With a SW grip, won't your palm be face down by itself?

    edit: I meant racket face, not palm
     
    Last edited: Aug 2, 2013
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  28. 10isfreak

    10isfreak Semi-Pro

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    Regardless of your grip, you can still move your hand just the same. What Nii says is that you have to turn your palm face down with relatively neutral wrist position at the end of your take back, just prior to your forward acceleration. The more conservative your grip is, the less closed your string bed will be at that point, but the important part is to turn your forearm as if you'd lay your hand on a table, palm down.

    That's why Nii says 'elbow pronation' and doesn't write a whole paragraph. For those who wonder, 'elbow' stands here because you can also pronate and supinate at your ankle... all this locution means is turn your hand palm down.'
     
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  29. sureshs

    sureshs Bionic Poster

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    ^^^ see my edit
     
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  30. 10isfreak

    10isfreak Semi-Pro

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    Supinate your forearm sufficiently and your string bed will be opened, even with a full western grip. It's not a fatality, as it goes. Besides, you can get it more or less closed with any grip.
     
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  31. KillerServe

    KillerServe Banned

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    For the swing path being most important for TS camp, how do they reconcile someone like Federer who gets almost the highest amount of TS on tour with a relatively flat swing path compared to others?
     
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  32. sureshs

    sureshs Bionic Poster

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    Depends on how fast he accelerates in the upward path. If he does it very fast, he doesn't need a steep incline to build up the upward and lateral component of speed.
     
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  33. KillerServe

    KillerServe Banned

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    So then you've just indicated that it's not in fact swing path that is most important, but rather RHS.
     
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  34. TimeSpiral

    TimeSpiral Professional

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    The swing path only needs to be such that it imparts TS on the ball. From there, RHS is the primary force creating RPM.
     
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  35. RetroSpin

    RetroSpin Hall of Fame

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    The beauty of what Dr. Nii has done is that it is not a matter of opinion or feel. He has documented exactly what is happening. Nadal hits the vast majority of his FHs on the bottom half. So do the other top players, but it is not as pronounced.

    It's very surprising there is not more discusion of this, as it would seem to have a lot of relevance for both racquet design and string tension.
     
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  36. boramiNYC

    boramiNYC Hall of Fame

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    highly doubt that. people who have made some close observations like john yandell said they couldn't detect no such a thing.
     
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  37. Ash_Smith

    Ash_Smith Hall of Fame

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    ^^^ Yep, when JY did some analysis of his video archive for another thread on this topic not that long ago he found it was roughly a 1/3 split - 1/3 below centre, 1/3 approx' on centre and 1/3 above (IIRC) and that was pretty standard among the players he looked at.
     
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  38. rkelley

    rkelley Hall of Fame

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    ^^^ Sounds like they're trying for the center of the racquet, and getting a bit of random variation above and below. And those folks are really good! I know for me, and my meager level of talent, I'm just trying to put the ball in the sweet spot. I shank enough as it is.
     
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  39. sureshs

    sureshs Bionic Poster

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    And that was contested on the grounds that he should have looked only for deliberate (i.e., unforced) strokes on which top spin was intended. And I think he did take these into account. But the debate never closed.
     
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  40. RetroSpin

    RetroSpin Hall of Fame

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    John is also skeptical of deliberate forward tilt. He said most of it is the result of below center contact. I have trouble with that.

    I don't want to get into a contest with John. Clearly, he is far more knowledgeable than I am. I will say that I have carefully reviewed Dr. Nii's work and am very impressed by it. He is also endorsed by a guy who is doing the most innovative work on golf mechanics, Kelvin Miyahira.
     
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  41. dominikk1985

    dominikk1985 Legend

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    the tennisspeed guy say that the racket already starts slightly closed (by a slight pronation of pat the dog move as the acceleration starts) but he also says players would intentionally hit below center to make the racket twist over the ball.

    he thinks that the pre contact closing is important but I think he thinks the main contributer is how low you hit the ball on the stringbed

    http://www.youtube.com/watch?v=U6icR4QaI84
    http://www.youtube.com/watch?v=TJDOqLmNAJk

    however I'm not sure if those hits are really wanted or in fact shanks, because as great as fed is he always was prone to shank a few (probably because of his extreme spin generation).
     
    Last edited: Aug 3, 2013
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  42. rkelley

    rkelley Hall of Fame

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    The thing is, at the end of the day you just want to hit the ball well. For me it's about swinging up for topspin and then I set the racquet angle to adjust height over the net. In the couple of hundred milliseconds that I have to decide what to do, that's about all I can handle.

    Then I just try to maintain the angle through the contact zone and put the ball on the sweet spot. If I manage to do that the ball goes pretty good.
     
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  43. Raul_SJ

    Raul_SJ Professional

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    The Cambridge study is saying that closing the face does not impart more topspin -- it only affects the height.

    Is that correct Coach Ash?
     
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  44. Ash_Smith

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    ^^^ yes, the study suggests that the angle of the racquet face affects the launch angle of the ball and that the path of the racquet affects the spin. That follows with my own 15 years experience working with high performance athletes.
     
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  45. Cheetah

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    Not boasting but I hit a pretty heavy ball on my fh. It's fast and has more spin than anyone I've played with. I can make it kick up above the shoulders or give it a flattish trajectory with the same rpm's or give it varying degrees of sidespin in both directions. My swing path is on the 'shallow' side. Not a huge degree of low to high. It's quite 'level'. Extreme sw grip.

    For me, closing the racquet face gives me more spin. Not because of the physics of the face angle or my swing path or hitting below/above/at center and combinations of all of the above but because it allows me to hit harder and keep the ball in. Closing the face affects the launch angle and trajectory so I 'need some closure' to control depth.

    This added control (for me; in my mind) allows me to swing faster thus allowing me more spin. I was taught many years ago by my coach at the time (ex pro from the early 70's) to close the face for more spin. He might have been incorrect that closing the face gives more spin but but I believed him at the time so it's ingrained.

    Also when i hit with a closed face it 'feels' different than with an open face. The ball 'feels' heavier (meaning it feels like the ball itself weighs more which forces me to hit w/ more body instead of arming it). It 'feels' like it stays on my strings longer. It feels like I have more control. It 'feels' like it digs into the ball more. It even sounds better to me. It's more of a 'fffFFFWOK!!' instead of just a 'POP'. These 'feelings' make me think I hit more spin with a closed face.

    Therefore for me... closing the face gives more spin. (or allows me to hit w/ more spin).

    That's my plan and I'm sticking to it.
     
    Last edited: Aug 6, 2013
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  46. GuyClinch

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    Testing it out with tennis warehouse shot maker thing - it shows basically no spin with a flat stroke and a slightly closed face..

    Tennisspeed guy seems to think this equation is wrong.. Not sure if I buy it. Those closed face allows you to really benefit from the WW swing - if you try it with an open or flatish face I think you launch a looper..

    Fed has a fairly modest uppercut to his swing but he really turns the hand (I guess tennisspeed guy calls it elbow pronation) very violently..
     
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  47. TimeSpiral

    TimeSpiral Professional

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    That makes perfect sense, but the racquet face angle is incidental to the spin you're generating. Where you're right on the money, is that "I'm going to keep doing what I'm doing." That's the take away here.

    If you want to hit with more topspin, practice hitting the ball with more topspin more. Sure, there are some very basic things you want to understand, but you do not need to know the physics.
     
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  48. sureshs

    sureshs Bionic Poster

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    This confirms my previous comments that closed face may provide more dwell time.
     
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  49. rkelley

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    The way something feels to a player and what's actually happening can be very different things. Cheetah said as much in his post.
     
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  50. rkelley

    rkelley Hall of Fame

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    From a physics standpoint closing the racquet face will create topspin relative to more open racquet faces. That's not a debatable point, it's just a fact. The thing is closing the racquet face will also change the launch angle of the ball all other things being equal. That also isn't a debatable point.

    How much topspin does closing the face contribute? I don't know, but as a player I really don't care either. I have to get the ball over the net and inside the baseline. If all other things in my swing remain constant, then racquet angle is the only tool I have to make that adjustment. I'm not going to think, "Wow, I want more topspin, I'll close the face." because I'll just drive the ball into the net. If I want more topspin I'll increase the vertical component of my swing. For a specific swing I'll adjust the racquet face to get the right distance over the net and inside the baseline.

    The racquet face angle has to account for the upward component of the swing (the more I swing up the more I need to close the face), the incoming trajectory of the ball (if I hit on the rise I have to close the face more), the incoming spin on the ball (the bounce takes away a lot of the initial spin, but a good slice will still have a lot less topspin than a topspin hit - the sliced ball needs a more open racquet face), how hard I'm going to hit the ball (close the face for a harder hit), and where I am on court (the further back I am the more I need to open the face to get the depth). With all of this going on, in the space of a few hundred milliseconds, I need to keep it as simple as possible. Swing path for more or less topspin, racquet angle for launch angle.

    I agree with Cheetah that if I hit harder I have to close the face, but I just think of it as a necessity of physics (see previous paragraph). Softer hits can be (should be) higher over the net. Harder hits have to go lower.
     
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