Vince Spadea's tips on FH and Serve

Discussion in 'Tennis Tips/Instruction' started by boramiNYC, Jan 30, 2013.

  1. sureshs

    sureshs Bionic Poster

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    What a stupid post.

    The force applied by one body on another is equal to the force applied by the other body on the other, during the collision. There is no net external force. There is a massive impulsive force each body experiences due to the collision.

    No one said acceleration is not involved. It is involved in the build up to the velocity. It does not matter if the velocity was built-up gradually as done by the pros, or by sudden acceleration before impact (which is not how the pros do it). The misconception arises because some people mistakenly teach that the pros swing abruptly hard just before impact, despite tons of evidence to the contrary. To support their theory, they insist on talking about acceleration at impact. Their knowledge is as poor as yours, and like you, they don't want to correct it either.
     
  2. Topspin Shot

    Topspin Shot Legend

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    Collisions have nothing to do with force. The equation for momentum is p (momentum)=mv, and the equation for collisions is m1v1+m2v2=m1v1'+m2v2'. The reason a big car would mangle a small car in a collision is because the big car has more mass (mass is part of the equation). Force is only applicable in terms of impulse, that is, change in momentum. Factoring the time of impact into the collision, the change in momentum of one object equals Ft. However, force and time of impact only have to do with the deformation of the ball or racket, not the exit velocity of the ball. For that, you have to use the momentum equation.

    To dispute what Oscar Wegner is saying, think of it this way. Would you rather get hit by a car that is traveling 10 mi/h but accelerating at 20 mi/h^2, or would you rather get hit by a car traveling 50 mph but decelerating at -20 mi/h^2? I don't know about you, but I would take the first one. The first one would knock me down, but the second one would kill me. So, when hitting any shot, the velocity of the racket at impact is what's important for outgoing ball speed, not the acceleration of the racket.

    By the way, I'm majoring in physics, so I have experience in these matters.
     
  3. sureshs

    sureshs Bionic Poster

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    ^^^ Don't even bother. They will repeat the Newton's laws, a vague comment about momentum being m*v, add a sarcastic insult, and go back to their ignorance.
     
  4. boramiNYC

    boramiNYC Hall of Fame

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    haha, sure.
     
  5. boramiNYC

    boramiNYC Hall of Fame

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    Exactly. This is physics 101. Shouldn't be too hard to grasp with a little bit of clear thinking.
     
  6. Topspin Shot

    Topspin Shot Legend

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    Thank you. May common sense return.
     
  7. boramiNYC

    boramiNYC Hall of Fame

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    10char....
     
  8. Povl Carstensen

    Povl Carstensen Legend

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    Hitting through is better than brushing for many shots, theres nothing new about that. Nor has anyone said anything else.
    No one has advocated brushing the ball or hitting backwards. What is good is that you are slowly comming around to acknowledging an across factor in the shot, as well as the up and through, that is really the major development here. And that took you a loong time.
     
    Last edited: Jan 31, 2013
  9. Povl Carstensen

    Povl Carstensen Legend

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    Lots of pros have lots of acceleration just before impact, you should know that. And imagine you throw a racket at the ball, and it hits when you are not holding it. Compare that with the racket is held and pulled through the shot, it makes for a different transfer of energy, not so hard to understand really. The weight of the body is suddenly involved in the shot, as opposed too if the hand is just passively "following through".
     
    Last edited: Jan 31, 2013
  10. Povl Carstensen

    Povl Carstensen Legend

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    Rich comming from you.
     
  11. DavaiMarat

    DavaiMarat Professional

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    Vince is simply reiterating what some players often forget to emphasize. As you carry the racquet forward (climbing the steps) toward your target you increase the force and accuracy of your shot. However as your path becomes longer and your arm extends out you lose some ability to effectively pronate and your shot becomes flatter. (The Push)

    On the other hand Oscar emphasizes the pronation phase. Pulling across the body to generate shot speed and spin. Much more a rotational emphasis which isn't incorrect either.

    You need good push and pull/finish to execute any shot effectively. So we need a bit of both execute with accuracy, margin and power.

    Stop acting if both are mutually exclusive of each other people. What matters is PAS, the ball doesn't care how you get there just what your racquet does when it's there.

    So Vince is just reinforcing the push phase because so many club players just see the finish and they don't realize how long the path was to get there so they over pronate and slap the ball. Also, these players are big guys. Look at the wing span of Fed. So while he still pronates his racquet has gone through much more of the strike zone due to his long wing span. Looks like he pronates more but in reality his swing is longer then most. Same holds true for Nadal as well.

    An example of a shorter player that tries to elongate his swing path is Tipseravic. You notice he looks a bit awkward some times in his follow-through? That's because he's trying to emulate the PAS of a taller (more powerful) pro. It's simple science.

    Why you guys get caught up so much in semantics and technical jargon is beyond me.
     
  12. Povl Carstensen

    Povl Carstensen Legend

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    Very very true.
     
  13. Povl Carstensen

    Povl Carstensen Legend

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    Imagine a volley blocked by a racket hung by a string. Imagine a volley blocked by a racket held by a player in the hand. It is two different strokes. So it is not just the racket alone, the racket is a part of a system with the arm and body, and the forces in this system make a difference.
     
  14. Povl Carstensen

    Povl Carstensen Legend

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    Would you rather hit the ball with a racket that is accelerating, or would you rather hit it with a racket that is decelerating is perhaps more to the point.
     
    Last edited: Jan 31, 2013
  15. sureshs

    sureshs Bionic Poster

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    The racket is accelerating into contact, even though the acceleration may be decreasing.
     
  16. DavaiMarat

    DavaiMarat Professional

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    This makes no sense to me. Unless you are talking about the kinetic chain in which the i.e. forearm may be decelerating while the wrist is accelerating (whip effect). Something can not be accelerating and decelerating at the same time.

    You can say the racquet head 'velocity' is still increasing but the delta (acceleration) is decreasing.
     
  17. sureshs

    sureshs Bionic Poster

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    I didn't say that.

    Velocity is still increasing.

    Acceleration is decreasing. Decreasing acceleration is not deceleration. Deceleration is negative acceleration.

    I am going by posted plots of speed and acceleration, though. It is not my own data, of course. What I remember is that the acceleration starts decreasing before impact, and actually becomes a deceleration after impact, at least for the forward component of the speed.
     
  18. DavaiMarat

    DavaiMarat Professional

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    So your just saying the delta is smaller then it was initially before impact correct? Very rarely will you get something trying reach peak velocity at impact that doesn't have a smaller delta (positive) then it did at the beginning (resistance, gravity, heat) all play a part. The greatest delta is probably as the player is coming out of the slot (pat the dog).

    Their is a common misconception of where acceleration is greatest. Though it may look like a player accelerate on contact (sorry nick) you're simply seeing the end of a long kinetic chain. The racquet is already moving plenty fast but the movement of the wrists and arms make an illusion of power at contact meanwhile the power/speed was already generated from the legs, waist and shoulder.
     
  19. sureshs

    sureshs Bionic Poster

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    Yes it seems the human body cannot sustain high accelerations for long.

    That is why it is an illusion that the acceleration is being increased at contact.
     
  20. Povl Carstensen

    Povl Carstensen Legend

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    Or, to combine the two: Would you rather be hit by a racket held loosely out of the window of a car going 40 mph, or by a racket held out of the window of a car going 20 mph and forcebly accelerated to 20mph (relatively to the car) at impact? I think there would be a difference of impact.
     
  21. Povl Carstensen

    Povl Carstensen Legend

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    Ok fair enough, that would depend on the specific shot I guess.
     
  22. sureshs

    sureshs Bionic Poster

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    Physical/biological systems cannot be accelerated abruptly like that on demand just before impact.
     
  23. Povl Carstensen

    Povl Carstensen Legend

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    Abruptly is a matter of definition. How much is that, half a second, 5 milliseconds, something in between?
     
  24. sureshs

    sureshs Bionic Poster

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    To go from 20 mph to 40 mph in 5 ms is an acceleration of 181 g, i.e. 181 times the acceleration due to gravity.
     
  25. Povl Carstensen

    Povl Carstensen Legend

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    I am not suggesting that. I am suggesting a resonable active racket head acceleration. But I am not surprised that you would imply that I was suggesting something that can not be done.
     
    Last edited: Jan 31, 2013
  26. Povl Carstensen

    Povl Carstensen Legend

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    Who volunteers?
     
  27. Povl Carstensen

    Povl Carstensen Legend

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    My theory is that accelerating puts tension in the tendons, they are pushed back by the inertia of the racket. Thus there is more weight behind the shot when you accelerate, than when you don't. More of the man-racket systemic weight goes into the shot.
     
  28. boramiNYC

    boramiNYC Hall of Fame

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    what about different magnitude of acceleration? say one is much bigger backswing accel at 10m/s^2 and reaches 40mph at contact vs. smaller backswing accel at 30m/s^2 and reaches 40mph at conatct vs. almost no backswing accel at 50m/s^2 and reaches 40mph at contact.

    So you are saying the last one has the most 'systemic weight'?

    What about accel at 100m/s^2 and reaches 20mph at contact vs. accel at 30m/s^2 and reaches 30mph at contact. Which would have faster ball?
     
  29. LeeD

    LeeD Bionic Poster

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    Post 126.
    Depends if the accelerating racket was still being accelerated at the moment of impact.
    If it's not, then inertia is the only answer....the same. An object going 40 mph has only that much momentum.
    Now grip strength at moment of impact, or no tension whatsoever, makes a difference, of course.
     
  30. bhupaes

    bhupaes Professional

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    Sorry about the bad job of quoting. In case you misunderstood, I was trying to point out that both aspects are used in tennis - building up racquet momentum, as well as accelerating through contact. If the racquet is moving at 50 MPH near contact, in 4ms, I believe it will cover 3.5 inches - you decide if that's significant or not. But let's drop this, since analogies can only be taken so far, and this one is no exception.

    Two further points...

    Povl's point that the process of accelerating will effectively put more body behind the shot (to paraphrase) is absolutely right. This is one major reason for accelerating near contact.

    However, the big hippo sitting on the living room couch that we are all ignoring is that the way this acceleration is done - using ISR, biceps to pull the racquet near contact - is a composite motion that will add forward, upward, and across components, and release a properly conditioned wrist. This will add a huge amount of RHS.

    I believe these two points embody the real reasons for accelerating near contact.
     
    Last edited: Jan 31, 2013
  31. sureshs

    sureshs Bionic Poster

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    It typically is.
     
  32. LeeD

    LeeD Bionic Poster

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    Not sure about that one.
    Our preswing and swing sets the acceleration, and maybe at impact, the head as already reached it's max velocity.
    Lots of players with high racket hands at trophy and long low finishes are NOT in this group.
    Most top servers have a high hand, high elbow, after impact, which shows the hand isn't accelerating thru impact with the ball.
    Now, is the rackethead stalled from further acceleration?
     
  33. sureshs

    sureshs Bionic Poster

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    Yes, due to impact
     
  34. boramiNYC

    boramiNYC Hall of Fame

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    This whole technical mumbo jumbo came about because of F=ma concept Oscar brought up regarding the contact. He and a few others here are not thinking clearly if they cannot agree contact is a collision and the conservation of momentum is the law governing any collision.

    nobody disputed about accelerating near contact and its importance. I also think it can increase solidness of the momentum of the racquet. Now there needs to be compromise between solidness and maximum velocity because V at contact is the most important variable for momentum for collision. trying to increase solidness reaches the point of diminishing return rather quickly because the contact is so short. if the v is sacrificed due to more solidness throughout the swing that would be arming the ball. and the hit would lose the potential.

    And there really is no hippo. This thread is simply about how a renowned pro thinks about what's important in FH and serve. the problem is some people have developed a knee-jerk reaction to the term 'through the ball' saying it's a conventional teaching and is wrong. The truth is it is conventional teaching but is not wrong. And it doesn't contradict up and across, so i see no problem.
     
  35. Topspin Shot

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    Povl Carstensen, there would be no difference between getting hit by a racket hung out the window of a car going 40 mph than getting hit by a racket accelerating to 20 mph in a car going 20 mph. 20 mph+20 mph=40 mph. 40 mph is 40 mph. Now, holding the racket loosely might lessen the force of impact because doing so would decrease the mass component of p=mv. What would happen is that the mass would be more along the lines of the mass of the racket rather than the mass of the racket plus the mass of the person holding it.
     
  36. sureshs

    sureshs Bionic Poster

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    Great post. The dichotomy between through and across is created artificially to make it appear that there is something revolutionary being said, and some pseudo-science has been inserted to give it respectability and confuse readers about the real facts which are contradicted by the claims.

    Vince has simply set the facts straight.
     
  37. bhupaes

    bhupaes Professional

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    I don't believe Oscar and the MTM folks are saying that the racquet does not go through the ball. That would be absurd. If we disagree here, you can ignore the rest of this post.

    The issue here is really instruction. How do you define "through the ball"? I am willing to take a bet that anyone who hears this term is going to think that this phrase implies that the racquet head should move straight through the line to the target. I certainly did. The instructor will then have to say, no no, not that way, hit through the ball but also move your racquet upwards. But is that really through the ball? More detrimentally, the image of moving the racquet straight through the ball, which will be the primary visualization with this instruction, will almost surely cause the student to exercise the kinetic chain suboptimally - this is an important point. It caused me a lot of confusion when I started playing. If you think the phrase "through the ball" will convey exactly the right stuff to the student, you can ignore the rest of this message.

    Oscar's approach, I believe, is to provide the cue and visualization that will cause the mechanics to be right from day one, with minimal confusion. The pulling action he refers to will give the through, up, and across components. With experience, the student will be able to vary the components as he/she gets more feel

    That is all there is to it. A difference in teaching philosophy, which I wish I had benefited from when I started playing many years ago.

    For those who don't agree, cool, do it your way. It's senseless to start this whole argument every time somebody says one should hit through the ball on youtube, and vilify Oscar and MTM endlessly.
     
  38. boramiNYC

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    bhupaes, I really have no problem with Oscar's stuff.

    but when Oscar uses a scientific concept that is inappropriate for a situation and does not make sense I feel the need to point it out for a debate. would have done the same to any poster.

    how come no one on MTM side is able to understand why that formula doesn't work is what bugs me. It's not as if suresh and I are conspiring against Oscar with this basic science stuff. I value making sense.
     
  39. sureshs

    sureshs Bionic Poster

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    Spadea cautions against use of the coming across terminology very vehemently - it is the wrong model for teaching. He says it about 5 times in the video. Peter Burwash said the same in a Tennis magazine article. Both these people are bonafide pros whose career details can be viewed by anyone.

    But people with common sense will disregard some of the teachings and look at pros and juniors for the right guidance and turn out all right. That is a different matter altogether.
     
  40. bhupaes

    bhupaes Professional

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    No problems, borami! I get what you are saying now.
     
  41. Povl Carstensen

    Povl Carstensen Legend

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    That is exactly what I mean also.
     
  42. Povl Carstensen

    Povl Carstensen Legend

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    I think you are disregarding my post 126 somewhat, or perhaps you just disagree.
    What I think is interesting is that my thought connects acceleration to mass. Due to the acceleration, the racket is more in contact with the weight of the arm and body. You so to speak increase the swingweight of the racket-body unit. Not unlike how firm/loose you hold the racket as you say. Inertia presses the racket back in the accelerating hand, connecting it more to the weight of the body and arm.
    So we are over the ma, and back to mv, but not looking solely at the racket m.
     
    Last edited: Feb 1, 2013
  43. Povl Carstensen

    Povl Carstensen Legend

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    I am not advocating sacrifying v.
     
  44. Mikael

    Mikael Professional

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    Spadea is right that proper extension is a key to great FHs and "derailing" the way he describes pulling away too early is probably the most common technical mistake at 4.5+ levels. It's too bad he just talked about extension vs pulling away, almost making people think of extension and rotation as two opposites. Then you get people trying to extend through the shot forcefully, which doesn't really work either.

    IMO, if you get the right rotation, and the right contact point, you automatically get great extension without having to consciously extend. The right rotation, ie, rotation through the spinal axis. People pull away from the stroke the way Spadea describes it when they rotate through the shoulder instead of rotating through the spine.

    Get the right kind of rotation going, and extension takes care of itself.
     
    Last edited: Feb 1, 2013
  45. Topspin Shot

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    Povl, I think I see what you're saying. Accelerating the hand at impact might very well increase the effective mass of the racket+body at impact due to the inertia of the racket. However, I'm pretty sure that any gain in power due to this phenomenon would be more than canceled out by the fact that if the racket is accelerating at impact, it has not yet reached maximum velocity.
     
  46. LeeD

    LeeD Bionic Poster

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    could some player's DEcellerate the hand to allow the HEAD of the racket to accelerate further?
     
  47. Topspin Shot

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    ^^^ Yes- it should happen naturally.
     
  48. LeeD

    LeeD Bionic Poster

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    Should it?
    Most players who show vids here do not slow down the hand, and keep the hand accelerating well past the ball strike, shown by their superlow hand at the followthru.
    I think it's a LEARNED proposition.
     
  49. Topspin Shot

    Topspin Shot Legend

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    Sorry, it is something learned. What I meant is that the player does not consciously think about slowing the hand during the stroke. With the right technique, it should happen naturally, kind of like pronation on the serve.
     
  50. TennisCJC

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    I think de-cel-ing the hand is basically a kiss of death on your ground strokes. You want legs/hips/shoulder to pull arm/hand and hand to pull racket head up/thru and across. The rotation should be smooth and accelerating into and thru contract until it flows/runs out in a WW follow-thru.

    The forearm pronates into WW follow-thru long after the ball is gone. If you want to de-cel something to speed up you RHS, try stopping your opposite (L) hip or even pulling your oppossite (L) shoulder back to speed up your racket shoulder.

    The hand/wrist should be very passive just before, during and just after contact. Don't screw with it.
     

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