slice serve - pronate or no pronate?

Discussion in 'Tennis Tips/Instruction' started by luvforty, Mar 3, 2013.

?

slice serve - pronate or not?

  1. yes, pronate

    45 vote(s)
    71.4%
  2. no pronate

    18 vote(s)
    28.6%
  1. LeeD

    LeeD Bionic Poster

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    The only player I can think of who uses pure slice is ElenaDementiava.
    Serena uses top/slice.
    Sampras HEAVY top/slice.
     
    #51
  2. nabrug

    nabrug Rookie

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    Last edited: Mar 8, 2013
    #52
  3. LeeD

    LeeD Bionic Poster

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    And that's a top/slice wide serve.
     
    #53
  4. toly

    toly Hall of Fame

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    Sorry, but my copy shows www.TheInnerSystem.com. Is this your website? The link doesn’t work.

    Btw, if you post the video as public then everybody can do with it whatever they want.
    I created my own YouTube library (http://www.youtube.com/channel/UCVtnV90bBCB50nkd8EQDFOQ?) by copying any interesting public video from internet.
    Anyway, I apologize for any inconvenience. :(
     
    #54
  5. toly

    toly Hall of Fame

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    #55
  6. LeeD

    LeeD Bionic Poster

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    That vid is just stupid.
    Girl is hitting a flat/slice serve, because she swings ....like a girl.
    Guy his slicing the ball into shreds, swinging half again the rackethead speed, and really cutting the ball.
    Girl's serve barely curves, but probably goes 75mph.
    Guy's serve curves for real, again going maybe 75, but moving off to the side 5'.
     
    #56
  7. nabrug

    nabrug Rookie

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    Some big artists put contents on youtube. Some people make money to create special video for youtube. You can't do with it whatever you want!

    I don't care about your library. You just copied it 1:1. In the civilised world that is called stealing. Now you can remove it yourself or I can youtube take care of it.
     
    #57
  8. toly

    toly Hall of Fame

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    I removed it!!!
     
    #58
  9. toly

    toly Hall of Fame

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    Here are examples of flat and slice serves.
    [​IMG]
    Both show solid arm pronation.
    The main differences are:
    1. There is very weak wrist ulnar deviation in case of flat serve and very active in case of slice serve.
    2. Path of the slice serve is directed more to the right.
    3. Flat serve has additional wrist flexing activity.
     
    #59
  10. arche3

    arche3 Banned

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    Is that sampras video shot by you? It looks like a televised broadcast. It looks like the innersystem website took a televised match and copied a portion to analyse.
    If you did in fact shoot the video of a public match I am not so sure you have exclusive rights to the content if posted. As the video itself contain no copyrightable claim. Noone is selling or profiting from a repost. In fact any repost advertises innersystem the creator (you?) of the video.
    If you copied the clip then its even less your rights of exclusive use.
    A music video or song has a valid copyright claim as the song is a controlled composition. In fact youtube plays of video containing controlled compositions (songs) do pay royalties to the rights owner if played enough.
    Please clarify why this sampras video is owned by you? I am curious.
     
    #60
  11. JimF

    JimF Rookie

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    Thanks Toly.

    Yandell (guy quoted on every pro spin stat ) agrees with you

    Sampras had more topspin on his serve than anyone, per JY, only 30%, rest side spin

    Part of the problem is semantics, people use "pronation" to mean many things that are not what the word originally meant.
     
    #61
  12. FrisbeeFool

    FrisbeeFool Rookie

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    Luvforty, if you want to use words like pronate, supinate etc, you need to pay a little attention to what they actually mean and how they are used in context. By misusing terminology like this and taking it out of context you are devaluing the meaning of these words. Most competent players use some variant of the continental grip and they all pronate. Some players use a grip a little closer to an eastern backhand grip for more topspin. They are pronating also. If you use the proper form with good shoulder turn and coiling, these grips orient the racket in the hand, in such a way, that u have to pronate to contact the ball cleanly. On a kick serve you're getting under the ball more and brushing up the back of it. You still pronate as you follow through and finish the stroke. Look at how Pete Sampras finishes his topspin serves. Look at his racket and hand and arm. Look at how they were oriented earlier in the stroke. What happened in order to change their orientation? In a word, pronation.
     
    Last edited: Apr 3, 2013
    #62
  13. FrisbeeFool

    FrisbeeFool Rookie

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    A ray of sanity in this crazy thread! That is a great way to explain it. If you're using the continental grip, and you're getting any type of power behind your serve you're pronating. The op's question reminds me of the thread that said the secret to pro serves was pancaking the ball with a frying pan grip. If I followed the majority of the advice in the instruction threads I wouldn't be able to even hit the ball in play.
     
    #63
  14. Chas Tennis

    Chas Tennis Hall of Fame

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    Path of racket & hand leading to impact.


    I like to think of the ISR for the serve as a Spiral Up. Biomechanically that is what the center of the racket face is doing in relation to the arm rotation when when viewed from above.
    https://vimeo.com/66720474

    I was looking for the 'spiral up' by looking at the Fuzzy Yellow Ball Salazar serve videos from above. A little spiral is there but the racket path is more straight than spiral.

    But whether or not it looks like a spiral from above also depends on the path of the hand movement. Your video composite pictures (what do you call them?) show hand movement very well.

    My concept has been more of getting the arm up, straight and rotating it without considering the path of the hand. Now I'm interested in the effect of the hand movement during ISR and how the hand's path affects the path of the racket face. The hand movement might help the racket face center track more in a line or to move more freely. More pace?

    Do you see what I mean, the spiral etc.? See the path of the hand moving out in your video composite picture above? What do you think?

    It would be good to check how representative Salazar's serves are in comparison to the current pro servers. Might be difficult to make comparisons without similar high speed video views from above. ?

    Your Youtube videos that contain the composite pictures add so much to the videos. I especially like the Stosur video, the ball trajectory really stands out.
    http://www.youtube.com/watch?v=QUwxiqFUi58

    Are your composite pictures available on a photo sharing site?

    (The rapid racket motion above lasts only about 0.02 second.)
     
    Last edited: Jul 21, 2013
    #64
  15. toly

    toly Hall of Fame

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    This is composite picture of Florent Serra’s spin serve.

    [​IMG]

    Due to it is spin serve, we can see a lot of wrist ulnar deviation activity. That’s why the tip of the racquet draws cone spiral with some distortion because of arm rotation (not ISR), body motions and some modest wrist flexion.

    All my posts with pictures and videos are public and not commercial, so you can do with them whatever you want. :)
     
    Last edited: Jul 22, 2013
    #65
  16. TomT

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    #66
  17. Chas Tennis

    Chas Tennis Hall of Fame

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    Remember the 2D camera viewing limitations for a 3D space? - the frame shows 2D well but the direction toward or away from the camera is not shown well.

    The interesting question for this picture is - how far out toward the camera is Serra's hand moving?

    All 3 Frank Salazar videos from above show a large component of hand motion out to the side away from his body/head as well as forward, estimating crudely, 45° out for the flat and slice serves and 60° out for the kick serve. Probably this Serra serve is similar to Salazar's serves and Serra's hand also comes out toward the camera. In your display for this video, Serra's later hand positions would display the 3D position more accurately if the later images were on top of the earlier images, especially the last frame at impact should be on top.

    Kinovea thread on your composite pictures -
    http://www.kinovea.org/en/forum/viewtopic.php?id=692
     
    Last edited: Jul 22, 2013
    #67
  18. toly

    toly Hall of Fame

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    Your slice serve video doesn’t show contact, so, it impossible to analyze. I found your 1st video in your thread.

    [​IMG]

    There are some comparisons of your actions with standard pros serves.

    1. In picture 1 – the racquet string bed plane is parallel to your back and behind the back.
    The racquet should be perpendicular to your back and on the right side of the body.

    2. In picture 3 - the racquet is completely open (the waiter’s tray position).
    The racquet string bed plane should be between vertical and semi open position.

    3. In pictures 4, 5 – The contact is very far to the right and very low.
    The contact should be between above your left and right shoulders.

    Nevertheless, your technique allows using ISR and wrist flexion very efficiently to maximize a ball’s speed. So, it can be very good for people with relatively slow serves.
    Good luck! :)
     
    Last edited: Jul 22, 2013
    #68
  19. TomT

    TomT Hall of Fame

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    Thank you toly. This gives me some specific things to work on should I need to try to significantly improve my serves. I shadow served a bit, using a continental grip and following your suggestions, after reading your post. I didn't feel any bad or unusual stresses. So, I suppose I could learn to alter my serve per your suggestions.

    I think it would take a lot of practice to get it to the consistency that I'm hitting my serve at now, albeit with a much better potential for spin and speed. But I hesitate to undertake that just yet, as my level of competition doesn't demand anything better than the way I serve now. Also, my current method of serving must be super easy on everything because I've never had any problems with stresses or strains either in the arm or shoulder from serving.

    I wonder how much my more or less eastern grip (as opposed to continental) is contributing to my current less than optimal serving mechanics?

    Also, to keep this as on topic as possible, I would say that I don't currently pronate on my slice serve. Correct?
     
    Last edited: Jul 22, 2013
    #69
  20. toly

    toly Hall of Fame

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    I described standard pros technique who can hit 130mph and faster serves. I think you don’t want it because it is not friendly on body. I’m old man and I’m going to learn your serve method, pros technique is not working for me anymore.

    About pronation see pictures below.

    [​IMG]

    You create ball’s speed mostly by using the wrist flexion, see picture 1. The wrist flexion rotates the racquet around 60° and this maybe too much. The internal shoulder rotation (pronation) rotates “not enough”, around 30°. If you change the grip to more continental, you would be forced to use less wrist flexion and more ISR (pronation). It is up to you.

    You also apply the wrist ulnar deviation (picture 2) around 45° and elbow extension very efficiently and create devastating side spin. :shock:

    Warning – slow down the elbow extension. There must be no elbow brake. :twisted:
     
    Last edited: Jul 23, 2013
    #70
  21. TomT

    TomT Hall of Fame

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    Ok. Welcome to the club. :) So, from what you say, I might as well just continue with what I'm doing, as I'm 65 years old? That's good to know. I can get about 90-95 mph serving this way, but usually can get away with serving even slower at my level (and also against higher rated players, but need to serve better against higher rated to win service games regularly).

    This would explain why the only side effect I've ever felt from serving is a little bit of soreness in the wrist. But not very bad. I mean, I have recently played a match per day for several days in a row with no ill effects.

    I'm experimenting sometimes with a more continental grip.

    Have been working on some slice serves, especially to deuce court, with good results (for my level).

    I don't know what this means.
     
    #71
  22. Chas Tennis

    Chas Tennis Hall of Fame

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    Regarding your wrist pain. I had some wrist pain and noticed a difference between my technique and that of the pro servers at the wrist.

    In frames 4 & 5, you can see that you have a similar angle (ulnar deviation) in your wrist to mine. Your video is not high speed so I can't exactly see the impact to compare to the pro. The pro has a straight arm at impact and his wrist is straighter and does not look stressed. All serve videos from behind show straight arms and wrist angles at impact that look similar. All the video thumbnails of serves from behind show impact, look at the wrist angles on the thumbnails. https://vimeo.com/user6237669/videos

    Your technique differs from what the pros are doing as shown. You are in unknown territory with your own technique. It could be very risky to find any new isolated fix for your serve and try to change it, especially mixing your technique with the current serving technique. Still, just as I'm also doing now, I would give some attention to your wrist, especially if there is any pain.
     
    Last edited: Jul 23, 2013
    #72
  23. toly

    toly Hall of Fame

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    Sorry, I meant elbow extension. Never straighten your arm completely, otherwise you can get tennis elbow.
     
    Last edited: Jul 23, 2013
    #73
  24. toly

    toly Hall of Fame

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    There are a lot of pros serving with bent elbow, see for example David Ferrer http://www.youtube.com/watch?v=Dh54JevAw78. In his case beta angle is not so important. :confused:
     
    Last edited: Jul 23, 2013
    #74
  25. Chas Tennis

    Chas Tennis Hall of Fame

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    That video does not show impact. The frame rate is not high enough to show the fastest part of the serve. In the 1st serve at 4 sec when the racket is edge on, his elbow was near straight when that particular frame was exposed. Or, maybe Ferrer does not have a proper service motion...?

    I believe that nearly all pro serves have a very nearly straight arm at impact. Also, that it bends very soon afterward to start the follow through.

    (I have read for athletics to always keep a few degrees of flex in the elbow joint - not fully extend it - to minimize the chance of hyper-extending the elbow and possibly cause injury.)
     
    Last edited: Jul 23, 2013
    #75
  26. TomT

    TomT Hall of Fame

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    First, thanks for the reply. I'm always interested to hear what people like you and toly have to say about anything. Very helpful.

    Now, regarding wrist pain or stress. Actually, for me it isn't exactly the wrist. It's more in the hand and centered in the base, the meaty part, of the thumb. I think I've figured out the reason for this. It's because of the eastern or 'frying pan' grip that I use on the serve coupled with my serving motion on slice serves. What happens, I think, is that most of the vibration which gets to the racquet handle is absorbed by the base of my thumb when I'm hitting slice serves. Not so much with the really flat hard ones, I think because on those my palm, rather than the base of my thumb, is absorbing the bulk of the vibration. With my newly acquired Wilson Pro Staff Classic 6.1 95 racquets, which are a bit stiffer and also have a bigger grip size and are strung tighter than my other racquets, I feel it more than with the other racquets (which I get virtually no stress or pain from using, no matter how much I play or serve).

    There would seem to be an easy fix for this. Just move the grip a little to the left (ie. continental) for slice serves, so that the palm of my hand, rather than the base of my thumb, is absorbing the bulk of any vibration transferred to the racquet handle. What do you (and toly) think? Should that do it, or will the change in grip also require some sort of change in the mechanics.

    Currently, I don't pronate. That's become clear to me. But I also don't like the occasional slight but noticable pain I get. So, will I need to pronate along with adopting a continental grip?

    Here's a couple more short vids of some serves:
    Serves Deuce Court
    http://www.youtube.com/watch?v=1UAw1-8p02A

    Serves Ad Court
    http://www.youtube.com/watch?v=wGE7qe_dfMo

    Enjoyed watching your vids. I downloaded Kinovea and am looking forward to playing with it.

    Yes, as per above, let me know if you think changing to a continental grip is advisable, and what else that might entail. Thanks, and if you're ever in Fort Lauderdale please contact me for a hitting session or even some match play. :)
     
    #76
  27. TomT

    TomT Hall of Fame

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    Ok. Thanks. I guess I've been lucky so far to have happened on a way of serving that's pretty much stress free for me. Except for the base of the thumb which can get a bit sore when I'm serving a lot of hard slices. I mention this in my reply to Chas. What do you think about changing to continental grip for slice serves?
     
    #77
  28. TomT

    TomT Hall of Fame

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    By the way, I finally voted no pronate, because I don't pronate.
     
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  29. toly

    toly Hall of Fame

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    I don’t accept typical tennis terminology about grips. There are 10 different and very confusing definitions of grips: – Pistol Continental, Pistol Semiwestern, , , Hammer Continental, , , Hammer Hawaii.

    I prefer my own:
    1. Continental grip – the wrist radius and ulnar deviations move the racquet in racquet string bed plane.
    2. Semiwestern grip - the wrist radius and ulnar deviations move the racquet in direction perpendicular to racquet string bed plane.

    According to my definition what grip are you talking about?

    Also, I’m not Medical Doctor and afraid to talk about medical problem.:(
     
    Last edited: Jul 23, 2013
    #79
  30. Chas Tennis

    Chas Tennis Hall of Fame

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    I take the approach of trying to understand - in adequate detail - what is going on with the current high level serve. The important biomechanical research for the tennis serve was published about 18 years ago by Elliott and others.

    The recommended grip is a continental or, for more spin, an eastern backhand, or between the two. I have seen a nice description of the reason but could not locate it. It may have mentioned the interference you are experiencing. ? I believe it allows the arm to proceed and rotate freely with less stress when using the effective motions of the serve. Internal shoulder rotation (misnamed pronation) is the largest contributor to final racket head speed.

    I looked at your last video and you have a strong and fast shoulder action that is getting you a very good serve. I can see that it is an effective serve.

    You are grooved with a lot of muscle memory for several motions that are not included in the current service motion: grip, minimal leg thrust, shoulder not so one-high one-low as discussed in the Ellenbecker video, an angle in your elbow at impact, etc. I think these things are very hard to change and that any incorrect part could be an injury risk. You also may have incorporated motions to accommodate stiff or injured joints, for example, not bending the trunk as much as the pros do to get that shoulder so high. The pros really get some contortions! However, your upper arm bone stays in line with the line between the shoulders even if the hitting shoulder is not as high as for the pros - see the Ellenbecker video.

    The edge-on rotation to facing-the-ball at impact is produced mostly by ISR. I believe that free motion in that phase of the serve is an important reason for the continental grip.

    In other words, I don't think it is as simple as changing a grip and practicing.

    Why don't you study the serve for a while?

    FYB – Continental Grip, see 1:39-3:42 - you need two points on the hand to position.
    http://www.youtube.com/watch?v=Hr2f8dmiwpU

    Brent Abel - Continental, Eastern Backhand Grip on In Between Grips
    http://www.youtube.com/watch?v=EmkW_kQYww8

    Discussion of Eastern Forehand to Continental Transition Issues for the Serve
    http://www.tennisone.com/newsletter/template/11.8.10.newsletter.html

    FAQ Grips
    http://tennis.about.com/od/instruction/a/faqgripsor.htm
     
    Last edited: Jul 24, 2013
    #80
  31. Attila_the_gorilla

    Attila_the_gorilla Professional

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    Just on the slice serve, in my opinion the big difference between pros and recreational players is the toss.

    At recreational level, you can get away with an exaggerated slice by putting your toss way out to the side. That ensures a glancing blow to the ball, most of the energy will go into creating sidespin and only a small energy goes into the forward motion. This is why at this level, slice serves are very slow, don't bounce much and are unplayable by an unsuspecting returner.

    On the other hand, pros can't get away with tossing the ball out wide cos that would telegraph the serve to their opponent. Once the returner sees the toss out to the side, he knows that the only possibility is a slow slice. This "telegraphing" makes the exaggerated slice unsuitable against quality opposition.

    So instead of this exaggerated slice, the pros use more subtle slices, tossing the ball where they would normally toss it for a flat serve but make a slight adjustment in their racket path and timing of pronation. They'll end up with a bit of side spin but still good power.
     
    #81
  32. GuyClinch

    GuyClinch Hall of Fame

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    Agree. Pros and good amateurs hit what I would call a power slice. Its got a lot of speed - some topspin and some slice. If you toss the ball out to the side its easy to come across the side and hit a very spinny slow slice. But its not a very effective serve.

    If you know baseball - a pro slice serve is like a cut fastball a lot of the time. That's how a pro I had hit them anyway.. Guy was pretty good went to the Bolleteri academy and everything - so makes sense to me.
     
    #82
  33. Attila_the_gorilla

    Attila_the_gorilla Professional

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    You don't really wanna add top spin though cos it'll turn it into a kick serve, which may be counter productive. From the deuce court, a wide slice is good, but a kicker would jump backwards towards the returner, defeating the purpose of going wide. From the ad court, a kicker is better cos it jumps away from the opponent's backhand. Assuming right handed players.
     
    #83
  34. Chas Tennis

    Chas Tennis Hall of Fame

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    Tom, Pat Dougherty has a video discussing eastern forehand serving and either keeping it or going to continental. He seems very familiar with the problem. When he first works at the fence he is demonstrating the eastern forehand grip - I had watched the video before and did not realize this. He is located in Bradenton, FL, maybe he has classes?

    http://www.youtube.com/watch?v=xjXJGsRtm08&list=TL_3vIZICZSpY

    I looked for information (Youtube or other) that I had once seen that discusses the reason to use the Continental grip. I believe, but don't know, that it mentioned interference that the eastern forehand grip can cause, including in the hand. Maybe it was the problem that is now causing your pain. The information was probably in some serving video and I probably won't be able to locate it.

    As a stop-gap fix, can you soften that part of the racket handle by taping a little of that dense foam white packing material where it bothers your hand? Also, holding the racket at the end of the grip might help.
    http://www.youtube.com/watch?v=EmkW_kQYww8

    Does your video camera have a high speed video mode?
     
    Last edited: Jul 24, 2013
    #84
  35. TomT

    TomT Hall of Fame

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    Not sure. But I think it's closer to 2 than to 1 on the serve. I definitely use a pistol grip on everything from the forehand side (including serve). Only use hammer grip on backhand side.

    Understood.
     
    #85
  36. TomT

    TomT Hall of Fame

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    Very helpful. Thanks.

    Thanks. I'll do some searching for relevant vids on this.

    I put a Gamma grip on it that has foam ridges built into it. They stick out about 1/16 in. or so and probably lessen the vibration going to my hand.

    I'm experimenting with moving my hand farther down the grip, basically holding with 3 fingers at the buttcap. Not just for the serve, but for other strokes as well. It seems to increase whippy action. Probably is lessening vibration to base of thumb also, as this part of my hand is almost totally off the grip. However, for stability and consistency I need to have my hand a bit higher on the racquet.

    Played a whole match yesterday with one of the stiffer racquets. Hand doesn't feel too bad. Just some mild discomfort on certain movements.

    No.
     
    #86
  37. TomT

    TomT Hall of Fame

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    Interesting. Thanks.

    Ok. I understand that it might be a bit more complicated than just changing to a continental grip, and maybe in my case not even advisable.

    I will take your advice and do some more homework. :)

    Thanks for the helpful references and comments.
     
    #87
  38. Chas Tennis

    Chas Tennis Hall of Fame

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    sorry, post by mistake. please delete
     
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  39. suryanaga

    suryanaga New User

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    You can get tons of action on the ball no matter if you use pronation or not, but pronation helps a ton with racquet speed and disguising the serve.
     
    #89
  40. Chas Tennis

    Chas Tennis Hall of Fame

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    mistake -----wrong thread ----------------delete
     
    Last edited: Feb 7, 2014
    #90
  41. RetroSpin

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    Lots of great insights in this thread. Well done guys.

    The issue of imparting spin on the ball has been studied in great detail in golf using both radar-based units, eg Trackman, and extreme high speed video, eg Phantom. Slice spin in tennis is the equivalent of hook spin in golf, ie, a ball that curves to the left. It is produced in either sport by a face angle that is closed to the face path.

    Thus, you can hit a slice serve by coming straight into the ball with the face closed. This serve often undermines the 3.5-4.0 player trying to hit with greater pace. They swing hard but only produce side spin.

    Similarly, you can hit slice by swinging out toward the net post in the ad court and meeting the ball with a square face. This is basically the serve tom is demonstrating above.

    Pros use a complex mixture of ISR, elbow extension, ulnar deviation and pronation to hit the ball with a square face and somewhat in to out path.
     
    #91
  42. Chas Tennis

    Chas Tennis Hall of Fame

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    To do stop-action single-frame on Vimeo hold SHIFT KEY and use RIGHT or LEFT ARROW KEYS.

    The differences are small - do stop action single frame around impact using the arrow keys.

    Kick serve - Notice that the racket face rises slightly during impact. The forearm-racket has more of an angle (50°/130°) to it at impact to allow the racket to continue up on the ball.

    Slice serve - notice that the racket face goes across the back (is it also hitting some side?) of the ball. The racket has reached its peak height, goes across and down. Forearm-racket angle at impact (43°/137°).

    Both serves use internal shoulder rotation.

    Kick serve.
    [​IMG]
    https://vimeo.com/27528701

    Slice serve
    [​IMG]
    https://vimeo.com/27528347

    Can you see the direction that the racket strings are moving? At 240 fps the frame rate is just enough to see it.
     
    Last edited: Feb 7, 2014
    #92
  43. sureshs

    sureshs Bionic Poster

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    There was a Serena video I had posted once, along with a coach's comments, which implied that she had almost no pronation on her slice serve.
     
    #93
  44. Chas Tennis

    Chas Tennis Hall of Fame

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    I recall something of that reply but not much. Blog with a 'Myth' busted? Typical of her serving? I don't believe it. Find a few serves of Serena in high speed video with little motion blur and a good camera angle. Make sure that impact can be seen with small motion blur.

    This website?
    http://www.fawcette.net/2012/01/tenni-pros-pronate-on-every-serve.html

    This video?
    http://www.youtube.com/watch?v=AshpV0lddGo&list=PL34D06330BA695EC8&index=1

    These pictures looks like ISR.
    [​IMG]

    The indicator of ISR is how the elbow turns as indicated by the shadows of the elbow bones or a marker such as a clothing line on the upper arm.

    I believe the videos above in reply #92 are typical of the high speed videos of high level serves viewed from the better camera angles.

    There are always odd serves that are not typical. I have a serve by Raonic where the swing looks normal. But something happened and the ball does not pick up any more speed than the racket. It stays close to the racket for some reason. ?
     
    Last edited: Feb 7, 2014
    #94
  45. RetroSpin

    RetroSpin Hall of Fame

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    Great videos Chas, but the shift+arrow didn't work for me.

    It did appear to me though that on the slice, he was going pretty much directly sideways, bu tonly at the last frame or two. I was expecting a bit more over the top movement.
     
    #95
  46. SystemicAnomaly

    SystemicAnomaly G.O.A.T.

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    I remember such a post some time back from someone (don't know if it was you). It may have even been a link to an analysis of Serena's serve. I recall that when I took a look at her serve for myself, I definitely saw evidence of pronation (and ISR).
     
    #96
  47. LeeD

    LeeD Bionic Poster

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    Perhaps, some pronation.
    Do you change grips between flat serves and slice serves?
    There ARE some mid level players chopping at their slice second serves.
     
    #97
  48. Chas Tennis

    Chas Tennis Hall of Fame

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    Did you stop the video and then hold the SHIFT KEY while pressing the RIGHT or LEFT ARROW KEY?

    If that does not work for you, you might catch these frames by pressing the play-pause button as fast as possible. Cumbersome.

    I have Windows 7, and use Firefox. Laptop is 2 years old. Fast internet connection. Both ethernet cable & Wi Fi work.

    Instead of viewing on Vimeo you could download from Vimeo and view it using Quicktime. QT is probably already on your computer or you can get the free version from the Apple site. QT does very nice single frame also using the arrow keys.

    Here is what you see

    The ball is in contact with the strings for, say, 4 milliseconds. Since the camera, at 240 fps, takes one frame every 4.2 milliseconds, you usually catch just one frame with the ball on the strings in various degrees of being squished. Sometimes it is very squished and other times hardly squished. Maybe the frame was caught soon after initial contact or maybe late after initial contact - within that 4 milliseconds that the ball was on the strings. Look at the frames
    1) before impact,
    2) impact, and the
    3) frame after impact.
    from behind those 3 frames show the travel direction of the strings on the ball.

    These two serves in reply #92 show contact nicely but it is only in those 3 frames of each video. For the slice the racket is going across and for the kick it is going higher in the next frame.


    A Stosur kick? racket goes higher but without seeing the kick bounce I am not certain that it is was kick serve. Watch the racket after impact.

    [​IMG]

    https://vimeo.com/40449544
    On this video the racket climbs for 3-4 frames after ball contact.
     
    Last edited: Feb 7, 2014
    #98
  49. RetroSpin

    RetroSpin Hall of Fame

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    That 's a great vid of Stosur. Clearly a big kicker from the impact position as well as the upward action. Lot of ISR. She gets into an extreme ESR position, before the SSC fires. Not Roddick-level but impressive never the less. I'm guessing not too many female pros get that much ESR.
     
    #99
  50. Chas Tennis

    Chas Tennis Hall of Fame

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    She also has a lot of extra forward upper body action - her head & eyes are definitely down before impact as you can see.
     

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