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The Serve: Twist Versus Forward Rotation

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  • BrianGordon
    replied
    jmtennis - great questions - thanks.

    There is of course some risk associated with trunk rotation but it is my experience it is no greater than the risk associated with playing tennis in general, or any sport for that matter. Most of back injuries seem to occur through a simultaneous combination of twisting and non-twisting torso rotations. The most dangerous is twist combined with extension often seen in preparation for the backswing.

    I've been fortunate not to have any back injuries in my many years of coaching. I'd like to believe this is due to good mechanics but maybe I'm just lucky. The lateral trunk rotation occurs before the twisting - they do not occur with significance at the same time (lateral - backswing; twist - upward swing). Further, the extent of lateral rotation is built in over time starting at about 5 degrees and progressing to about 25 degrees. Even 25 degrees is pretty moderate and fortunately the most required to transfer forward angular momentum.

    Pronation of the forearm is insignificant - the forearm acts as transmission for the internal shoulder rotation but is not independently pronated, in fact the opposite, research has indicated it is supinated slightly on average. The wrist goes to a neutral position from muscular contraction of the wrist flexors - this is not a motion dependent event - internal shoulder rotation tends to drive the wrist into extension, not flexion.

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  • seano
    replied
    From what I've read - The lateral tilt has been known to create problems in the lumbar region if focused on at too early of an age, better to focus on after puberty. I like the following phrase - ''coaches must address different mechanical features at various phases of the developmental pathway. Specifically, preparing the body segments can be taught from a young age, however the propulsive movements do not begin to mature until after the onset of puberty".
    Last edited by seano; 10-15-2018, 06:12 PM.

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  • jmtennis
    replied
    I have watched your videos on the serve and have read your articles. Very good information I understand the leg drive and hip driving up and angular causes the racquet drop.I am concerned about the trunk rotation for young players during growth spurts. Will it not cause back problems?
    also is there pronation or does the wrist go to a neutral position from the rotation of the upper arm from the upper swing through contact. isn't it similar to a quarter back passing a football?

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  • seano
    replied
    Thank you Brian

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  • bottle
    replied
    Thanks.

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  • BrianGordon
    replied
    Most of the discussion seems to relate to the independent shoulder motion relative to the trunk. Keep in mind that in the upward swing the cartwheel has been completed and the main torso rotation has changed to twist about a laterally tilted torso axis. The cartwheel's main role is to transfer forward angular momentum (rotation) toward the arm during the backswing.

    In the upward swing there is independent rotation of the arm at the shoulder in for lack of a better term abduction/adduction (anatomically hard to describe). That motion along with twisting of the torso (derived from the forward rotation) account for most of the racquet head speed in the first third of the upward swing. These contribute in about equal proportion, roughly 40% each (Gordon and Dapena, Journal of Sports Sciences, 2006).

    In general, the positioning of the elbow from independent non-twisting rotation of the shoulder will not (and should not) violate the 100 degree rule due to the afore mentioned lateral tilt of the torso axis.

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  • BrianGordon
    replied
    Originally posted by seano View Post
    Brian - I have several questions about the latest serve video (Rotations in Upward Swing).

    1) Is it a correct assumption that the synchronization of the lower and upper body is that the leg drive initiates the racquet drop?
    2) The racquet to the outside in the external shoulder rotation portion (racquet lined up with the elbow exiting the backswing and entering the upward swing), is that a technique issue or a flexibility issue?
    3) 2 parts - a) When raising the elbow in the upward swing, is that the beginning of the somersault motion and lateral tilt of the trunk?
    b) When raising the elbow, does the shoulder abduction angle remains constant thru out (100 - 110 degrees?)?
    4) The wrist flexion you mentioned after internal shoulder rotation, is that to bring the wrist to a "neutral position"? I know you are only talking about the upward swing that takes place before contact.You're not suggesting to flex the wrist further than that, correct?
    5) What are your thoughts on the serve tip - "to achieve greater external rotation of the hitting shoulder, in "full racquet drop" try to keep the elbow higher then the hand".

    Thanks again for your input.
    1- That is one of 3 roles of the leg drive - think I will cover that coming up.
    2- Both
    3- See separate post.
    4- yes, flexion to neutral.
    5- seems feasible.

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  • bottle
    replied
    Take Me Seriously, Please, Anybody, You're All Good

    Turn off the sound and go to 1:14 of the video. Play that sequence of Federer's upward rotations over and over. Just get on 1:14 and click click click again and again.

    This ought to resolve the questions just brought up. Ought to but won't. Some question still will remain: Is there independent raising of the elbow or not?

    Note that left elbow appears to go down at the exact same rate that right elbow goes up.

    Does that argue for no independence of elbow? Or for matching independence of BOTH elbows?

    To implement what is best for oneself there can be absolutely no doubt at all?

    A few more of same click from 1:14 . Now I think the left elbow goes down faster than the right elbow goes up.
    Last edited by bottle; 10-13-2018, 03:22 PM.

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  • bottle
    replied
    I watched the video again. I know it's all about sequence, but when one watches, one may see, or think one sees, as I just did, the fast independent elevation of the elbow coming neither before nor after the lowered racket tip moving out to the right but just then. In conjunction with all kinds of energy starting in the lower body. Am looking forward to this change. And may have gotten carried away with the javelin image.

    But something like that can happen when you leave the text of a complicated blueprint and start implementing all on your own-- which you have to do, it seems to me, I can't see any other choice. Unless one wants to live forever in a blueprint.

    That said, it could be helpful to study the blueprint, implement like mad, return to blueprint, implement again, etc., etc., back and forth until the outcome is great. One thing for sure: This blueprint is great and a person ought to try to carry it out as best he or she can.
    Last edited by bottle; 10-13-2018, 10:47 AM.

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  • bottle
    replied
    Originally posted by seano View Post
    My understanding with the elbow position in the upward swing, is to keep a constant angle between the elbow, shoulder and side of the trunk (shoulder abduction angle). I've heard the angle should remain constant at 100 - 110 degrees. Was asking Brian to see if that is true. When you start to tilt your body (lateral flexion) you are bring the contact point higher up and not to the side. A common mistake with the tip to "scratch your back" is it raises the elbow too high, leaving 2 problems. 1) less room to accelerate up 2) increase risk of injury (impingement of the shoulder).
    I just have trouble with this line of discourse as it doesn't seem to include the independent arm rise, the "adduction" that JY once talked about and is talking about again in his most recent promotion of TennisPlayer. Is there an independent sling of the upper arm or is there not? It can't be the same thing as the elbow rising and the racket tip going down and out to right. That wouldn't help the arm then to passively straighten. And if the javelin throw I'm trying to suggest does exist, it has to happen after elbow is lined up with the clavicle or shoulder balls or whatever, no (?), so what maximizes it (?). This is about both language and conception of the serve, no? I just think all of this has to be perfectly and precisely hammered out in someone's mind if he is going to progress. And in this case the someone is I.

    Am I wrong? Is there not a separate javelin throw where elbow, bent a lot or some, is the javelin? Should we be totally solid as elbow accelerates, and this is why the words "lift of the shoulder" and not "lift of the upper arm" were used? Semantics, semantics, I suppose, but terribly important, at least to me.

    I see a big consciousness change in the passive or motion-dependent arm straightening. I'm there and happy with this development in my serves. But the question is what's best to happen just before.
    Last edited by bottle; 10-14-2018, 06:12 AM.

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  • seano
    replied
    My understanding with the elbow position in the upward swing, is to keep a constant angle between the elbow, shoulder and side of the trunk (shoulder abduction angle). I've heard the angle should remain constant at 100 - 110 degrees. Was asking Brian to see if that is true. When you start to tilt your body (lateral flexion) you are bring the contact point higher up and not to the side.
    A common mistake with the tip to "scratch your back" is it raises the elbow too high, leaving 2 problems. 1) less room to accelerate up 2) increase risk of injury (impingement of the shoulder).
    Last edited by seano; 10-12-2018, 11:42 AM.

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  • gzhpcu
    replied
    Elbow higher than hand, better racket drop, I would think.

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  • bottle
    replied
    Originally posted by seano View Post
    Brian - I have several questions about the latest serve video (Rotations in Upward Swing).


    5) What are your thoughts on the serve tip - "to achieve greater external rotation of the hitting shoulder, in "full racquet drop" try to keep the elbow higher than the hand".

    Thanks again for your input.
    If elbow's too high, how are you going to give it a good throw? (Image for this: a javelin throw.)

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  • seano
    replied
    Brian - I have several questions about the latest serve video (Rotations in Upward Swing).

    1) Is it a correct assumption that the synchronization of the lower and upper body is that the leg drive initiates the racquet drop?
    2) The racquet to the outside in the external shoulder rotation portion (racquet lined up with the elbow exiting the backswing and entering the upward swing), is that a technique issue or a flexibility issue?
    3) 2 parts - a) When raising the elbow in the upward swing, is that the beginning of the somersault motion and lateral tilt of the trunk?
    b) When raising the elbow, does the shoulder abduction angle remains constant thru out (100 - 110 degrees?)?
    4) The wrist flexion you mentioned after internal shoulder rotation, is that to bring the wrist to a "neutral position"? I know you are only talking about the upward swing that takes place before contact.You're not suggesting to flex the wrist further than that, correct?
    5) What are your thoughts on the serve tip - "to achieve greater external rotation of the hitting shoulder, in "full racquet drop" try to keep the elbow higher then the hand".

    Thanks again for your input.
    Last edited by seano; 10-12-2018, 11:28 AM.

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  • arturohernandez
    replied
    I haven't tried that drill but that actually seems to be a good idea for showing how the looseness leads to a better serve. My guess is that if one hits the serve while releasing the racket it would have a very interesting effect. I'll try it. Thanks!

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