Seriously About Pronation and Kick Serve #1

Discussion in 'Tennis Tips/Instruction' started by toly, Dec 24, 2010.

  1. gzhpcu

    gzhpcu Professional

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    Yes, it is not the forward movement of the forearm, it is the rapid rotation of the entire arm, whipping the racket forward.
     
    #51
  2. toly

    toly Hall of Fame

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    It is the main idea of this thread. Thanks gzhpcu for clarification.:)
     
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  3. shindemac

    shindemac Hall of Fame

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    Pronation comes naturally if you don't try to force it and stay relaxed.

    Most beginners will arm their serve, and end up with a sore shoulder. To help the average weekend warrior, that needs to be fixed and the kinetic chain needs to be explained so they know how and why that generates more power than arming their serve.
     
    #53
  4. toly

    toly Hall of Fame

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    There is no problem. It was funny. I also got drunk yesterday.
    Thanks. Happy x-s.
     
    #54
  5. toly

    toly Hall of Fame

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    I play tennis around 11 years. It was irregular weekend stuff before my retirement 6 months ago. One of my regular partners is 6 times Ukraine champion; he has title The USSR Tennis Master. He is 12 years younger than me, but I’m still able to compete with him. So far I’m OK. It is funny; I dare sometimes to coach him. He also teaches me. This is two ways process.
     
    Last edited: Dec 28, 2010
    #55
  6. Manus Domini

    Manus Domini Hall of Fame

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    I understand some of it, but it doesn't contain helpful types or instruction on how to hit the ball. Which is what this section is for

    it is good to be able to calculate all of it, but helps not one bit on a court
     
    #56
  7. gzhpcu

    gzhpcu Professional

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    First step is understanding, then applying is something else.
     
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  8. toly

    toly Hall of Fame

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    This 40% data I found on internet somewhere and I’m sorry I just don’t remember where it came from. I asked some MDs about forearm and upper arm contribution. The answers were: these questions are very complicated and perhaps nobody in the world knows the correct answer!
     
    #58
  9. Manus Domini

    Manus Domini Hall of Fame

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    understanding high level physics and understanding a stroke are completely different things...
     
    #59
  10. gzhpcu

    gzhpcu Professional

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    Most of the time, but here the message seems clear to me: keep a relaxed arm, use a continental or backhand grip to accentuate the angle between racket and forearm, keep shoulders and arm more or less inline.
     
    #60
  11. toly

    toly Hall of Fame

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    Of cause my math model is very simplified version of the real kick serve. But, even in this case a lot of people cannot understand it.
    When I got this stuff myself, I begun using pronation forcefully, it helped me to increase power and consistency. For example, for overhead, I usually used too much wrist flexion, as result the boll often hit my legs or fence. It is almost impossible to control wrist flexion. Right now I use just pronation for overhead stroke and always put the ball into opponent’s part of the court. It seems the pronation power is sufficient to produce very powerful smash.
     
    Last edited: Dec 29, 2010
    #61
  12. toly

    toly Hall of Fame

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    Seriously About Flat and Kick Serve

    2.2.2 The Flat Serve with Intensive Arm Pronation, Wrist Flexion, and Restrained Wrist Ulnar Deviation
    Figures below give us an idea about arm actions during typical flat serve.
    [​IMG]
    Figure 2.15. The arm’s actions during Marat Safin's flat serve
    [​IMG]
    Figure 2.16. The arm’s actions during Kevin Anderson’s flat serve

    In case of the typical flat serve the main components of the racquet speed are: the fast arm pronation, the fast wrist flexion and slow vertical arm rotation. If players are employing Continental grip, all these motions mostly create the flat component of the racquet speed and practically no spin. The most important would be the arm pronation.
    It follows from these photos, during the pronation phase of the flat serves both players keep their right elbows in bend position. In all previous analyzed spin serves, most pros maintain their arms during pronation phase practically straight.
    Question: Why during the pronation phase, these players keep elbows in bend position?
    Answer: When we swing the racquet upward our shoulder joint brings the upper arm in vertical and the forearm in horizontal position. After that, by using fast elbow extension, the forearm moves upward and the pronation angle β equal 90 degrees (Fig. 2.15.1). If the elbow unbends completely, it brakes and inevitably the racquet starts moving upward by using inertia and very fast wrist ulnar deviation. This motion reduces the pronation angle beta (Fig. 2.15.4 β=45°) and can kill pronation component of the racquet speed. To prevent it from occurrence, even during the impact, the elbow joint should be bent. Next pictures (Figure 2.17) illustrate Andy Roddick’s arm action during flat serve and confirm last statement.
    [​IMG]

    Figure 2.17. Andy Roddick's arm actions during flat serve
    Pay attention on the angle between axis of the upper arm and the forearm. This angle is never less than 30 degrees. Andy constructs the motion which often called as elbow snap. Maybe this is the main secret of his so successful flat serve. For instance, Marat Safin during impact keeps his elbow straight (Fig. 2.15.4). That’s why, perhaps, his serve is slower than Roddick’s. But, Marat straightens his arm at the very last moment before impact by using the elbow extension. This motion doesn’t have enough time to decrease significantly pronation angle beta, and produces just spin (not flat component). Hence, it enhances the serve’s reliability.
    In everyday life, when we “pronate/supinate” a screwdriver, for example, we always unconsciously keep elbow in bend position to increase a force applied to the screwdriver’s handle. The same natural motion Andy applies to the racquet’s handle. He uses bend elbow as some kind of “force multiplier”. I think, it doesn’t make any harm if this force would be very active during impact. This screwdriver approach could be very handy to overcome the inertia’s resistance of the tennis ball and hence, increase its speed. Bent elbow also increases radius of internal shoulder rotation and thus boll’s translational speed. To increase the flat component of the racquet speed all the best servers also apply the wrist flexion.
    I believe, we can keep the bend elbow before and during impact even in case of the kick serve, but with deliberately active the wrist ulnar deviation. It could help to curb excessive activity of the wrist ulnar deviation and hence keep the appropriate amount of the pronation angle beta (not less than 30 degrees).
    To be continued, see please post #63.
     
    Last edited: Mar 1, 2013
    #62
  13. toly

    toly Hall of Fame

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    Seriously About Serve Grip

    There is one more way to keep pronation angle β in proper range 30° - 45°
    We may also use slightly modified Continental grip. Next picture shows what kind of the grip Taylor Dent brings into play for flat serve.
    [​IMG]

    Figure 2.18. Taylor Dent uses modified Continental grip
    Taylor keeps his finger knuckles parallel to the long axis of the tennis racquet. With this type of the grip it is physically impossible to align the long axis of the racket in parallel to the axis of the forearm (fist grip) and hence, impossible to kill the pronation component of the racquet’s speed. In fact, the pronation angle cannot be less than 30°. I would recommend this grip for any type of the serves, except the slice serve.
    To be continued, see please post #76.
     
    Last edited: Feb 24, 2012
    #63
  14. akamc

    akamc New User

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    Elbow flexion/extension

    Thanks for your efforts toly, this (the elbow bend) was exactly the missing bit I was looking for. Great job putting this thread together... and don't let the naysayers who don't have anything to contribute but complaints ("make me a 5.0 for free and without too much work") or the usual banalities (like "I'm such a great player that I can't learn anything from you 'cuz I can't read") bog you down.
     
    #64
  15. akamc

    akamc New User

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    Grip

    I had also always wondered about the best grip for serving and here is one well-reasoned answer. I am going to try to switch to a fist grip for the ace!
     
    #65
  16. toly

    toly Hall of Fame

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    Thanks for your understanding and support.:)
     
    #66
  17. tennis_eel

    tennis_eel Rookie

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    Taylor Dent is looking fit...
     
    #67
  18. dozu

    dozu Banned

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    darn, just made a dent in the ceiling when I was trying to find the optimal beta angle.
     
    #68
  19. bhupaes

    bhupaes Professional

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    Agreed, I also do this. Makes the overhead a lot more consistent.
     
    #69
  20. bhupaes

    bhupaes Professional

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    I believe toly meant the net effect of pronation, including shoulder rotation. As I have said earlier, I don't believe pure forearm movements can contribute significant power. Pure forearm movements only help with racquet positioning and with directing of forces generated by the more powerful components of the kinetic chain.
     
    #70
  21. toly

    toly Hall of Fame

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    Hey OrageOne. You always push me on the edge of the abyss, and I like it. You have very good point,
    “Where's the shoulder in the above? Why is the shoulder the most injured part of the serve - and yet it supposedly contributes nothing, or at most some of the 10% of the upper arm?”
    I have no medical background at all. This would be pure speculation. I think the muscles, which produce forearm counterclockwise rotation, are connected not just to elbow bones, but to shoulder bones too. TIW, extreme forearm rotation can provoke shoulder injury.
    Btw, according to the picture, forearm can generate angular speed around Ω =4000°/sec (40%) and upper arm just Ω =1000°/sec (10%). It is true, because together they produce around Ω =5000°/sec-6000°/sec. I would definitely miss this very important information without you. Thank you very much.
     
    Last edited: Dec 27, 2010
    #71
  22. toly

    toly Hall of Fame

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    Be careful please, especially after or during x-mas party. :confused:
    But, the optimal angle beta is really very, very, very important!!!
     
    Last edited: Dec 27, 2010
    #72
  23. toly

    toly Hall of Fame

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    Yes, very fit, tiw he quit tennis.:(
     
    Last edited: Dec 27, 2010
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  24. OrangeOne

    OrangeOne Legend

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    Sorry, they are not. Right there you are suggesting that tendons from the pronators travel the length of the Humerus and connect to the shoulder. With all due respect, that's plain stupid. There would be a strange tendon structure travelling on top of the bicep!

    Muscles only traverse one joint through their tendons, not two. With all due respect, doing all of the analysis you've done and then suggesting such a thing is somewhat laughable.

    Please don't guess as to injury reasons after stating that you have zero medical knowledge. It takes years of study to properly diagnose injuries.

    Movement of a limb can cause injuries further up the limb, but your reason why is wrong.

    A. I doubt the above, but that's subjective.

    B. Angular speed is ignoring the size of the movement, and the momentum required. A small muscle may move very fast - but that's not going to help a major movement.

    Put another way: I can blink my eye faster than I can pronate my forearm, but then my eye muscles are smaller than my pronation muscles which are smaller than my upper-arm-unit. Speed is only relevant when considered with size - power is indeed speed * strength.

    So sure, maybe I can pronate my forearm quicker than I can move my upper arm unit. BUT the upper arm unit can achieve so much more due to the size of the muscles involved, and the fact it's at the top of the lever unit that is the arm-racquet.
     
    #74
  25. LeeD

    LeeD Bionic Poster

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    Serious here.
    Got to play today, 1st time in two weeks.
    I tried a twist toss, but a pronating forearm on the swing, and the ball went straight left and over the fence, me lefty with a conti towards eBACKhand grip. On a fly, maybe over 100 mph. I use the same grip on ALL serves.
    So next 30 tries (during a doubles set, as is most of my practicing), got some twists to bounce well over 6' just behind the baseline, but not hitting the backboard on the initial bounce....without pronating....or barely pronating, can't tell as I can't see myself at the end of my swing.
    Are you sure you can use the same grip, pronate on flat serves, then pronate also on heavy topspin serves swinging UPWARDS??????:shock::shock:
     
    #75
  26. toly

    toly Hall of Fame

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    Topspin Serve

    [​IMG]

    Figure 1. Andy Murray topspin serve
    Take a look at Andy Murray. He definitely is going to hit topspin serve. His grip is continental, because the racquet string is perpendicular to the court ground. He is going to use the wrist fast ulnar deviation to produce heavy topspin. If we employ eastern backhand grip, the racquet would be semi closed. And automatically around 50% of the racquet kinetic energy will be wasted to produce topspin component of the ball velocity and hence only 50% on the straight linear ball speed. In this occasion, we practically don’t need the wrist ulnar deviation. This grip makes it easier to generate topspin, but we lose around 50% of the boll speed. I think, tiw Nadal switched his grip toward continental/eastern FH grip and got much more powerful serve. :)
    To be continued, see please post #86.
     
    Last edited: Sep 25, 2011
    #76
  27. Ajtat411

    Ajtat411 Semi-Pro

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    The pictures, angles, analysis and everything is great if you understand these concepts already but it's another thing to put this into practice. If you want to progress your serve into an effortless motion, I recommend either video analysis or a pro/coach that knows how to serve.

    There really isn't a really good way to describe an effortless and powerful serve until experience it the proper technique. It really feels like your arm is a limp noodle and it's effortless.

    In the beginning it will feel like you're bearly getting any power into your serves, but one day it will click and you can really begin to practice real serves. You just have to be mentally ready to practice through the days that your serve feels/looks like nothing. It's ok, though, in the beginning it's all about form, not power.

    In tennis, if you goal is powerful strokes, it all comes down to racket head speed. The most efficient way to get power is really counter intuitive, more power in does not equal more power out. Think of your arm and racket as a whip, to get that whip to make that powerful snapping noise, you don't just muscle the whip, you have to work with the whip's flexiblilty to get it to snap. Think of your racket head as the tip of a whip, for power, your goal is to make that racket head produce that "snap" as if it's a whip. Pronation at the end of a serve is one key to the snap, but other areas of the service motion need to be there for it all to work effectively, otherwise you just end up injuring your wrist. :)
     
    Last edited: Dec 28, 2010
    #77
  28. LeeD

    LeeD Bionic Poster

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    I'm not sure if Andy's topspin serve photo has any bearing at all on a twist/kick serve swing technique. Except the more spin you add, the less speed you get for both serves.
    Consider. How is it possible to 1. use the same grip.
    2. pronate on both serves
    3. one serve goes 110, the twist goes 60mph
    ????????? just don't make sense.
     
    #78
  29. toly

    toly Hall of Fame

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    On all pictures I posted in this thread, all players use the Continental grip only. And they are able to perform flat, kick and topspin serve with intensive pronation! Why do you ask, “How is it possible to “? It is possible, because they are doing that without any problem.
     
    Last edited: Dec 31, 2010
    #79
  30. toly

    toly Hall of Fame

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    When we hit the pure flat serve, we don’t have to use the wrist ulnar deviation at all, to produce spin. By using elbow bend technique and/or Tailor Dent continental grip, we can easily keep pronation angle beta more than 45 degrees. Hence, the pronation efficiency will be more than 70% (see post #7, fig. 2.9). In case of kick serve we are forced to use very fast wrist ulnar deviation to produce heavy spin. This motion creates not only spin, but also decreases pronation angle beta. This motion is very difficult to control, because it is very fast and providing appropriate timing become very difficult task. If angle beta = 0°, pronation efficiency would be 0%. It means we kill pronation component of the racquet velocity completely, thus the ball speed can be even less than 60 mph. But, we get a lot of spin.
     
    Last edited: Dec 31, 2010
    #80
  31. toly

    toly Hall of Fame

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    Thanks. Good point.:)
     
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  32. dozu

    dozu Banned

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    slightly off topic - but this is the 'human racket' concept I have been referring to (surprisingly it provided a few good laughs)..

    if you whip the 'arm and racket' (while the whip stays flexible) for a powerful serve, shouldn't a FH be just the same? In another thread where JollyRoger had a few clips posted... he's got a nice serve and he was whipping that arm/racket unit for the serve, but you can clearly see that he was trying to whip only the racket for his FHs.
     
    #82
  33. LeeD

    LeeD Bionic Poster

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    So, are we talking DEGREES of pronation here? I think we should be.
    For flat first serves, conti grip, a full pronation to flatten the impact.
    For twist/kick serves, much LESS pronation, but some, and much more slicing upwards motion.
    Is that acceptable to you guys?
    I DID mention I used a twist toss location, pronated fully, and almost hit a flat serve up around 12' and off to my left, me lefty.
     
    #83
  34. Mr_Shiver

    Mr_Shiver Semi-Pro

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    Given all this data and analysis are there any tips and techniques that have been proven wrong or at least less important than we thought? I keep my strokes quite compact and would like to trim my serve of any excessive motion.
     
    #84
  35. shindemac

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    Read post #77 again. It's a good summary of this thread, and tries to explain what I boil down to a few words. It's about staying relaxed and using the kinetic chain.

    Most intermediate players and below end up arming their serve. They don't see the results from using proper technique, and go back to swinging from their shoulder. Then they complain about shoulder injuries. Unfortunately, most players still need to learn/master the basics before they can move on to more advanced things.

    I know how tough a journey this can be, because I'm going through the same thing. It's easy to say stay relaxed, use the kinetic, bend your knees, etc. But I know I'm on the right path because I'll get glimmers where everything clicks, and my serve will have more power than I ever could by arming it. Even without a radar gun, I can tell because of the sound of the impact, how the ball hits the fence, and the sound my arm makes through the air. Also, the serve feels effortless to do, and there's no tension in my body.
     
    #85
  36. toly

    toly Hall of Fame

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    Digging effect

    Digging effect
    There is one more problem with spin serve. Sometimes the spin component of the racquet speed (wrist ulnar deviation) cannot produce any significant ball rotation, but can change considerably the ball direction and speed. For instance, if the point of contact is the sweet spot and the flat (pronation) component has very big speed. The ball just digs into string bed; the strings hug the ball very hard and do not allow creating any ball’s rotation during “digging” phase of the impact. Then strings catapult the ball very fast and the spin component (wrist ulnar deviation) does not have enough time to rotate the ball. However, while the ball is in digging and catapult phases, the spin component still moves the racquet in its direction and as a result it varies the ball’s direction and speed. In the end of this complicated process we can get pure flat serve instead of the planned spin serve and the ball would move in wrong direction. To avoid this trouble, we have to keep starting point of contact away from the sweet spot. See picture below.
    [​IMG]

    This picture shows typical ball positioning in the beginning of the impact in case of the kick serve.
    Btw, we shouldn’t change angular range (amount) of the pronation, because it is almost impossible to control and doesn't make any sense. Always keep the range of the arm pronation around 90°.
    To be continued, see please post #124.
     
    Last edited: May 27, 2013
    #86
  37. Ajtat411

    Ajtat411 Semi-Pro

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    Yes, this also applies to the FH and BH and Overheads. I'm not sure this applies to volleys though, since in some cases a firmer arm helps add power to this shot and there really shouldn't be a real swing involved. What do you think?

    There's really no right or wrong way of hitting a ball as long as you're hitting through the ball at the angle you want for a particular shot at the moment of impact. Whatever idiocynracies you want to add or remove from your swing is up to you. Look at all the top players, they all have different looking swings but they all have one thing in common, when they need to hit a flat ball, their racket face is square with the ball at contact and everytime they want to hit a slice, they racket face is angled.

    So you're strokes can be as compact or long as they need to be for you to play your best. If your serve has excessive motions that is holding you back from a smooth and balanced serve, then I would get a pro/coach to look at it or video tape it. If the excessive motion are just harmless idiocyracies, then it doesn't matter.
     
    Last edited: Dec 28, 2010
    #87
  38. toly

    toly Hall of Fame

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    enough problem

    I think we shouldn’t pay too much attention to the legs and torso action. I observed so many times pros can hit so powerful overhead without any legs and trunk motion. Boll bounces around 20’ and sounds like thunder.
    There is enough trouble with arm actions, especially during spin serve. We should first of all think about Target plane, supination, pronation, elbow bend and/or Dent grip, ball positioning, and wrist ulnar deviation.
     
    #88
  39. Ajtat411

    Ajtat411 Semi-Pro

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    Shiver, you should really think about seeing a reputable coach/pro. They should be able to point you in the right direction within 1 lesson. Trying to get advice on the internet is very dangerous because you really need to piece together the information in the right way or else you'll be wasting your time practicing in the wrong way. Remember, practice only if it's perfect practice or close to it. :) Unless you want to stay at your current level forever.

    It really depends if you want to revamp your serve or continue and get the most out of your existing service motion. I chose to revamp mine from the ground up and it was a hard choice but I'm glad I made that choice because my old motion was holding back a lot of energy and at the same time expended a lot of my energy and caused soreness. How do you think top pros go day in and day out serving 120 without major issues? Their motion is sound and efficient plus preventative exercises, but it's mainly in their efficient/smooth technique.
     
    Last edited: Dec 28, 2010
    #89
  40. Mr_Shiver

    Mr_Shiver Semi-Pro

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    Thanks for the replies. I have seen a number of different pros (I have moved a lot) and it seems like they all add something or change something. It gets my brain all muddled. I don't like muddle. Muddle sucks.
     
    #90
  41. charliefedererer

    charliefedererer Legend

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    #91
  42. usta2050

    usta2050 Rookie

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    I agree, continental grip is more powerful. but Toly, have u researched grip shape vs grip vs serve speed? I think grip shape can make a little difference?

    Thank u for all the great info.
     
    #92
  43. toly

    toly Hall of Fame

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    Again problem

    Can you be more specific? Sorry, but I’m Russian (very bad with English) and just cannot comprehend your questions.
     
    #93
  44. toly

    toly Hall of Fame

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    Wimbledon 2010 Serve statistics
    Kevin Anderson
    Anderson vs. Davydenko
    1st Serve % 130 of 192 65%
    Fastest Serve Speed 135 mph
    Average 1st Serve Speed 123 mph
    Average 2nd Serve Speed 107 mph
    Second Serve Speed Decrement = (123-107)/123x100%=13%

    Andy Roddick
    Roddick vs. Yen-Hsun Lu
    1st Serve % 129 of 189 68%
    Fastest Serve Speed 137 mph
    Average 1st Serve Speed 123 mph
    Average 2nd Serve Speed 107 mph
    Second Serve Speed Decrement = (123-107)/123x100%=13%

    These guys (second serve compare to first) lost only 13% of the ball speed. In your example, you lost (110-60)/110x100%=45%. It means you are doing something completely wrong.
     
    Last edited: Jan 10, 2012
    #94
  45. LeeD

    LeeD Bionic Poster

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    Those stats are worthless for this discussion.
    First of all, they are SECOND SERVE stats, not twist serve stats. Topspin second serves are usually hit much faster than pure twists.
    Having watched countless pro men's matches, very few pro men second serve at nearly 100 mph. Some do, yes, but very few, especially on clay.
    Are you now gonna cite the ONE time PistolP aced someone with a 125mph second serve?
     
    #95
  46. toly

    toly Hall of Fame

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    How can clay affect serve’s speed?
     
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  47. gzhpcu

    gzhpcu Professional

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    All it can do is slow down the ball more after the bounce due to greater friction, but certainly no effect on the initial speed.
     
    #97
  48. gzhpcu

    gzhpcu Professional

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    Don't follow you LeeD. The racket comes up on edge regardless what type of serve you hit. It must open to hit the ball. The relaxed arm will continue pronating after impact. The timing of the pronation might be different, but it is there all the same. The swing path will be different and this will determine whether the serve is flat, topspin/slice or kick.
     
    #98
  49. toly

    toly Hall of Fame

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    About relaxed arm and wrist in particularly

    I found very interesting article, by Prof. Rod Cross.
    He stated, “Why do players stretch the fingers of their free hand? Don’t ask me, I don’t know. My guess is that when players tense their muscles to hit a shot, they tense all their muscles, not just the ones they need to tense (about 95% of them)”.

    [​IMG]
    Right now, I’m not so sure about relaxed arm and wrist in particularly during the serve and any tennis stroke! What do you think about that?
     
    Last edited: May 28, 2013
    #99
  50. Ajtat411

    Ajtat411 Semi-Pro

    Joined:
    Apr 15, 2009
    Messages:
    591
    ^This is a split second before impact. You need to activate your muscles just prior to ball strike to get that extra racket head speed, there's no way around it, unless you want to dink the ball over the net.

    The relaxation is prior to impact all the way until this moment just before contact. You still want relaxation in arms/wrist during the majority of all strokes though.

    Similar to Bruce Lee's philosophy on punching. Relaxed until almost the moment of impact to activate the fast twitch muscles.
     
    Last edited: Dec 30, 2010

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