No "Pet The Dog" on 2HBH?

Discussion in 'Tennis Tips/Instruction' started by TheLambsheadrep, Feb 6, 2013.

  1. julian

    julian Hall of Fame

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    How long is backhand?

    How long is a forward swing for a double handed backhand (in miliseconds)?

    In the case of FOREHAND the corresponding number is below 250 miliseconds
     
  2. julian

    julian Hall of Fame

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    Does Nadal double handed backhand better that one of Djokovic?

    Does Nadal double handed backhand better that one of Djokovic?

    If yes why?
     
  3. WildVolley

    WildVolley Legend

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    I'd argue that Djokovic has a better 2hbh than Nadal, but that's only from casual observation and I have no statistics to back it up, and I'm not sure the difference is simply a matter of form. I believe that Nadal tends to close the racket face more in the takeback than does Djokovic, or at least at the end of the takeback. Do you know of any sources with hard data on Djokovic and Nadal from match play? I think it is only a matter of time before we can get good computer data from something like shot-tracker that IBM used to provide at big tournaments.

    Julian, I don't know about the length of the swing in milliseconds (doesn't that depend on how hard the person is swinging, or am I misinterpreting your question?). Are you getting these measurements from high speed video?
     
  4. julian

    julian Hall of Fame

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    Elbow flexion vs elbow extension

    Is it possible to say anything about elbow extension of the RIGHT HAND of Nadal for his double handed backhand?
     
  5. WildVolley

    WildVolley Legend

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    Here's a link to Nadal hitting some bhs that I'm looking at.

    https://www.youtube.com/watch?v=j86FuSXtWUM

    Watching that, it doesn't look as if Nadal's technique is radically different from Djokovic's. I still see more elbow flexion at the takeback stage with little or no 'pat-the-dog' and slight elbow extension into contact.

    I think we can say a lot of the difference is that both Djokovic and Nadal have low take backs on the 2hbh and do not have the same sort of "pat-the-dog" motion into contact as on the fh-wing. But I'm seeing a lot of commonality in the two players' backhands.
     
  6. julian

    julian Hall of Fame

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    Last edited: Feb 19, 2013
  7. julian

    julian Hall of Fame

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    Local experts

    Local experts say that a across double handed backhand of NADAL
    is better than his DTL.
    Julian wondering whether it is a correct statement
    and why it is a correct statement
     
  8. WildVolley

    WildVolley Legend

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    I really don't know about that, but it may be possible to get data from someplace.

    I'm not sure that the match data completely answers the question between the two players because Djokovic has improved his game considerably in the past couple of years and even a player who loses a match may be superior in a given stroke.

    The thing that is more intriguing to me at the moment is the strong commonalities between the 2hbhs of Djokovic and Nadal. Can you specify a strong difference between the two players? I'm starting to see a lot of commonalities and fewer differences.
     
  9. EP1998

    EP1998 Semi-Pro

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    this is the backhand I want...(who doesn't) :)

    Maybe not big takeback but he gets such a good turn maybe it seems that way? But I think perfectly timed and he can hit the ball early.
     
  10. EP1998

    EP1998 Semi-Pro

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    If you mean my level, i have been playing since i was a little kid but I am still need tons of work. My backhand has always been reliable but I would not describe it as a weapon.
     
  11. julian

    julian Hall of Fame

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    Grips

    Do you think grips at THE CONTACT are the same?
     
  12. WildVolley

    WildVolley Legend

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    They seem fairly close. I think that Nadal's right hand is slightly more of a standard semi-western than Djokovic's left hand. But it doesn't seem to be a large difference. I think Djokovic is holding almost an extreme eastern, but I can't see clearly enough (the resolution isn't high enough for me to tell).

    Is that your impression of the grips? I think the other hand isn't as important as I think both hit an off-hand dominant stroke.
     
  13. julian

    julian Hall of Fame

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    How far away is a contact?

    How far away is a contact? (from a body)
     
  14. Power Player

    Power Player G.O.A.T.

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    This is one of the money questions.
     
  15. WildVolley

    WildVolley Legend

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    To estimate this well we would need some video shot either from directly behind or directly in front of the player and also to the side.

    On the forehand side, for instance, Federer, Nadal, and Djokovic hit the ball away from the body more than players like Nishikori who keeps his elbow closer to his side. On the bh side, I think it is interesting to note that Djokovic keeps his left arm straighter at contact than he does his right arm at contact when hitting a fh. That might not mean the ball is any farther away, because the right hand limits the motion of the swing to some extent on the 2hbh.

    When I have time I'll look for some videos with the angles we'd want for Nadal and Djokovic.
     
  16. julian

    julian Hall of Fame

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    A straight hand

    A related question is:
    is the bottom hand straight at THE CONTACT?
    It would allow to calculate the distance
     
    Last edited: Feb 22, 2013
  17. julian

    julian Hall of Fame

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    I have it

    I have a shot from the REAR-the only problem is that it is on tennisplayer
    Please do NOT angry at ME about it-just happened like that
     
  18. julian

    julian Hall of Fame

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    500 fps

    The one I saw are 500 fps
    At some moment (very close to contact) the BOTTOM hand is straight.
    It is a DIFFERENT model that SOME SHOTS by Agassi
    It is complicated because:
    on ONE HAND (pun attempted) one would like to have a hand straight
    (after coming OUT of THE FLIP but very close to the CONTACT).
    So we would like to employ SSC of biceps here
    Some references related to SSC below
    PS #1
    J Appl Physiol. 1999 May;86(5):1445-57.
    Length dependence of active force production in skeletal muscle.
    Rassier DE, MacIntosh BR, Herzog W.
    Source

    Human Performance Laboratory, Faculty of Kinesiology, The University of Calgary, Calgary, Alberta, Canada T2N 1N4.
    Abstract

    The sliding filament and cross-bridge theories of muscle contraction provide discrete predictions of the tetanic force-length relationship of skeletal muscle that have been tested experimentally. The active force generated by a maximally activated single fiber (with sarcomere length control) is maximal when the filament overlap is optimized and is proportionally decreased when overlap is diminished. The force-length relationship is a static property of skeletal muscle and, therefore, it does not predict the consequences of dynamic contractions. Changes in sarcomere length during muscle contraction result in modulation of the active force that is not necessarily predicted by the cross-bridge theory. The results of in vivo studies of the force-length relationship suggest that muscles that operate on the ascending limb of the force-length relationship typically function in stretch-shortening cycle contractions, and muscles that operate on the descending limb typically function in shorten-stretch cycle contractions. The joint moments produced by a muscle depend on the moment arm and the sarcomere length of the muscle. Moment arm magnitude also affects the excursion (length change) of a muscle for a given change in joint angle, and the number of sarcomeres arranged in series within a muscle fiber determines the sarcomere length change associated with a given excursion.

    PS #2
    J Biomech. 2003 Sep;36(9):1309-16.
    Stretch-induced, steady-state force enhancement in single skeletal muscle fibers exceeds the isometric force at optimum fiber length.
    Rassier DE, Herzog W, Wakeling J, Syme DA.
    Source

    Faculty of Kinesiology, Human Performance Laboratory, University of Calgary, 2500, University Dr. N.W Calgary, AB T2N 1N4, Calgary, Canada.
    Abstract

    Stretch-induced force enhancement has been observed in a variety of muscle preparations and on structural levels ranging from single fibers to in vivo human muscles. It is a well-accepted property of skeletal muscle. However, the mechanism causing force enhancement has not been elucidated, although the sarcomere-length non-uniformity theory has received wide support. The purpose of this paper was to re-investigate stretch-induced force enhancement in frog single fibers by testing specific hypotheses arising from the sarcomere-length non-uniformity theory. Single fibers dissected from frog tibialis anterior (TA) and lumbricals (n=12 and 22, respectively) were mounted in an experimental chamber with physiological Ringer's solution (pH=7.5) between a force transducer and a servomotor length controller. The tetantic force-length relationship was determined. Isometric reference forces were determined at optimum length (corresponding to the maximal, active, isometric force), and at the initial and final lengths of the stretch experiments. Stretch experiments were performed on the descending limb of the force-length relationship after maximal tetanic force was reached. Stretches of 2.5-10% (TA) and 5-15% lumbricals of fiber length were performed at 0.1-1.5 fiber lengths/s. The stretch-induced, steady-state, active isometric force was always equal or greater than the purely isometric force at the muscle length from which the stretch was initiated. Moreover, for stretches of 5% fiber length or greater, and initiated near the optimum length of the fiber, the stretch-enhanced active force always exceeded the maximal active isometric force at optimum length. Finally, we observed a stretch-induced enhancement of passive force. We conclude from these results that the sarcomere length non-uniformity theory alone cannot explain the observed force enhancement, and that part of the force enhancement is associated with a passive force that is substantially greater after active compared to passive muscle stretch.
     
    Last edited: Feb 22, 2013
  19. julian

    julian Hall of Fame

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    A petit favor

    Maybe it would be a good idea to specify videos you use
    (probably via links)
     
  20. julian

    julian Hall of Fame

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    Do u have any specific suggestions?

    Do u have any specific suggestions?
    Can I do anything specific to investigate?
     
  21. WildVolley

    WildVolley Legend

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    Here's the video of Djokovic I've found. He hits backhands at the beginning and end.

    https://www.youtube.com/watch?v=Z_lywtCEci0

    I don't see a lot of separation of the left arm elbow from the body, but a little.

    It seems that there is a fairly standard 2hbh form with a low takeback, slight elbow extension during the forward swing of the top hand so that it is mostly straight at contact, racket dip before contact is made, and slight extension from the body.

    I also checked out some video of Safin and his doesn't look terribly different. He also has a non-loop takeback, left arm elbow extension into contact, with a mostly straight left-arm at contact and separation of the left arm elbow from the body, but not a huge distance.

    It seems that it wouldn't be too difficult to teach this shot using Djokovic as a model for the student to emulate.
     
  22. TheLambsheadrep

    TheLambsheadrep Professional

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    Been looking over the discussion, very good job guys! I did, though, find a video on the subject on virtualtennisacademy.com called Backhand Stretch Reflex. Sign up for the website and check it out
     
  23. julian

    julian Hall of Fame

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    How much did u pay for it?

    How much did u pay for it?
     
  24. TheLambsheadrep

    TheLambsheadrep Professional

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    it's a free site, a lot of good info to be found
     
  25. WildVolley

    WildVolley Legend

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    If I get the time, I'll do this.

    The main benefit I've gotten from this thread is a better understanding of Djokovic's bh form.

    I personally have been experimenting with a little more arm-bend and loop into the backswing, and therefore more elbow extension into the hitting position, but I'm uncertain as to whether it is worth the trouble or gives significant gain. The players who I've been watching as models (Djokovic, Nadal, Gulbis, Safin) all have a lot of similarities including a c-takeback and only slight elbow extension of the top-hand into the shot. Interestingly enough, we can say that all these players hit with the top arm essentially straight at contact. I don't pay as much attention to the lower hand arm, as I don't believe it is dominant with any of these players.

    So the straight-arm form, rather than the double-bend, is the preferred technique of the majority of the great 2hbh-players in the men's game today, and something I believe is to be preferred over the bent arm type shot that Ferrer hits. My operating assumption is that the straight-arm allows more easy racket head speed.
     
  26. julian

    julian Hall of Fame

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    Another good post

    Please see
    http://tt.tennis-warehouse.com/showthread.php?t=455783
    post #12 by John Yandell
     
  27. WildVolley

    WildVolley Legend

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    Interesting post. Yandell discusses two things, the extent of the arm bend and which hand is more dominant. He says
    1) the Williams sisters hit more bent arm and more open stance, like an off-arm forehand &
    2) many of the men hit straighter arm and more closed stance and with more bottom hand dominance.

    I just went and played with some shadow swings and find that I can swing from an open stance with a straight left arm (I'm right handed). So I'll need to go on a court and see what problems this creates. Because you have to reach over with the bottom hand, the shoulders can't be as open as on a single handed forehand, but I still seem to be able to generate plenty of racket head speed.

    I think it may have more to do with the takeback and balance, but that's just a hypothesis.
     
  28. LeeD

    LeeD Bionic Poster

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    Most 2hbh use eastern forehand for the oft hand grip, and conti for the strong hand.
    For eastern forehand, you don't need "pat the dog" ...
     
  29. WildVolley

    WildVolley Legend

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    But LeeD, Federer is famous for his "pat-the-dog" and he often hits with something close to an eastern fh.

    I agree it isn't needed. The question is whether there's benefit to doing it anyway?
     
  30. julian

    julian Hall of Fame

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    Lee D

    Lee D maybe talking about double hander backhand only
    Idk
     
  31. always_crosscourt

    always_crosscourt Banned

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    So what are the advantages of patting the dog on backswing?

    Does it give more spin?

    And if so, how?
     
  32. WildVolley

    WildVolley Legend

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    I guess my answer would have to be I don't know what the precise advantages are, though I have some theories. At a very basic level, it sets the racket face more closed such that you can swing hard and not open it too much. It also seems to set a specific sort of racket lag which causes supination then followed by pronation. Whether this creates a stretch shortening cycle, or just forces the player to contract hard to pronate isn't clear to me. But the motion does seem to create more topspin.

    Essentially, the closed face "pat-the-dog" elbow extension is being used a lot by today's top players. It doesn't seem to simply be an affectation, so people are trying to emulate it, thinking it has something to do with the quality of shots the pros are generally creating. SpeedMaster's blog highly touts it as crucial in creating topspin with a flatter racket path.

    I guess I'd advise you to try it yourself and see if it helps your hitting.
     
  33. WildVolley

    WildVolley Legend

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    LeeD specifically mentions the eastern fh stroke. My impression was he was comparing an eastern fh to a 2hbh.

    I think we'd both agree it isn't needed, but whether it is beneficial is a different question.

    What is happening on Djokovic's and Nadal's 2hbhs isn't a traditional "ptd" but they're hitting well anyway with just a slight elbow extension into the shot. So I agree it isn't needed, I'm still just wondering if it might be a good idea.:confused:
     
  34. LeeD

    LeeD Bionic Poster

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    Yous seem to forget, the 2hbh is not hit with as much topspin as a forehand.
    Meaning, it's closer to old school eastern forehand than it is to new school SW forehand, in spin and ball speed.
    Even Nadal hits his 2hbh with less spin, oftentimes more ball speed, than his SW forehands.
     
  35. julian

    julian Hall of Fame

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    Straight arm

    Please see videos in
    http://www.golfloopy.com/role-of-right-arm-in-golf-downswing/
     
  36. WildVolley

    WildVolley Legend

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    Interesting article and the motion does seem analogous to what is happening with the top hand when Djokovic, Safin, Nadal, Nalbandian and Gulbis hit their 2hbhs.

    The top hand arm should be basically straight at contact and the bottom hand arm should adjust to allow the top hand arm to be dominant at contact. The arm moves from semi-bent (not as much as with the golf swing, but then the golf swing is much bigger) and then straighten during the pivot and swing.

    The big difference between this and the fh is that the fh has the straightening taking place at the end of the backswing and with a more outward and downward pressing motion (the 'ptd') and then sort of locks into a preferred position. The 2hbh top hand arm is changing and straightening more during the forward motion.
     
    Last edited: Feb 28, 2013
  37. TheLambsheadrep

    TheLambsheadrep Professional

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    Anyone check out the virtualtennisacademy videos?
     
  38. julian

    julian Hall of Fame

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    Computer problems

    I signed up but I cannot there-some computer problems
     
  39. julian

    julian Hall of Fame

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    Is it only elastic energy?

    Combined effect of elastic energy and myoelectrical potentiation during stretch-shortening cycle exercise

    C. BOSCO,
    J. T. VIITASALO,
    P. V. KOMI,
    P. LUHTANEN

    Article first published online: 8 DEC 2008

    DOI: 10.1111/j.1748-1716.1982.tb07024.x

    © 1982 Scandinavian Physiological Society

    Issue
    Acta Physiologica Scandinavica
    Acta Physiologica Scandinavica

    Volume 114, Issue 4, pages 557–565, April 1982

    Additional Information(Show All)

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    Abstract
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    Keywords:

    Muscle mechanics;
    stretch-shortening cycle;
    muscle elasticity;
    muscle activation;
    myoelectrical potentiation

    In addition to the utilization of muscle's elastic energy enhancement of performance in exercise involving stretch-shortening cycle might be also due to simultaneous increase of myoelectrical activity. This hypothesis was tested by examining three athletes during jumping exercise on force-platform. Vertical jumps were performed with and without preliminary counter-movement, and the jumps were called counter-movement jump (CMJ) and squatting jump (SJ), respectively. In both conditions several jumps were performed also with extra loads on the shoulders (15–220% of b. wt.). Additional droppingjumps (DJ) were executed from different heights (20–100 cm). During jumping exercise myoelectrical activity of selected muscles from the quadriceps femoris was monitored with surface electrodes. The results obtained were similar to those reported in isolated muscle and as expected, the prestretch in CMJ shifted the force-velocity curve of concentric work to the right. In two cases enhancement of performance was attributed primarily to restitution of elastic energy because myoelectrical activity was similar to that observed in SJ. In one subject increased myoelectrical activity was observed during the concentric phase of CMJ. In DJ condition the EMG activity during eccentric phase was much higher than in SJ. Therefore the high performance in this condition was attributed to both elastic energy and reflex potentiation. In eccentric work of CMJ the average force decreased with the increase of stretching speed. This phenomenon was associated with a light increase of EMG activity. The observed results emphasize that both elastic energy and reflex potentiation may operate effectively during stretch-shortening cycle activity.
     
  40. julian

    julian Hall of Fame

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    I saw the tape

    I saw the tape
    Do you have any specific questions about the tape on backhand reflex?
     
  41. TheLambsheadrep

    TheLambsheadrep Professional

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    No questions for now, but I thought it was a good video for the topic. In my opinion, hitting a forehand has your arm supinate then pronate naturally, I don't need to put any extra effort or thought in to have it occur. On the backhand though, it does not feel natural with the popular grips (maybe a little bit more with my more extreme grip, but I think it's because of my lower (R) hand). Does anyone share the same opinion?
     
  42. julian

    julian Hall of Fame

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    Hope

    There is hope that WildVolley will watch the videa.
    Otherwise we are cooked
     
  43. WildVolley

    WildVolley Legend

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    I haven't had time to watch the video. I may attempt to sign up and watch this weekend.

    My general opinion on this topic is that the limited range of motion and difference in shoulder angles is the main difference between a 2hbh and a left-handed fh. You can ptd with a 2hbh, but the motion is going to look different because of the other hand being on the racket. If this theory is correct, then you should also see a similar difference with players who hit 2 hands on both sides. There aren't many top players on the men's tour doing that today, but there have been in the past. I may look at some of their video if I have the time.
     
  44. julian

    julian Hall of Fame

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    I saw the video

    I saw the video mentioned by TheLambsheadrep
    The sign up works-I goofed with the signed up FIRST because lack of my computer skills
    There is a drill to practice supination followed by pronation
    PS The video is "hidden" in the backhand section.
    The search engine should help
     
    Last edited: Mar 8, 2013

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