Have a Question for Me?

[johnyandell]

I want to see numbers. I think we have to be careful about making quantitative statements without any quantitative data. But again, to me I think the explanation while if it can be substantiated is certainly interesting, is still less important than the simple execution of the positions.

[10splayer]

Makes sense what you guys are saying. My thoughts are that in the kinetic chain the energy is always transferred from one part of the body to the next. Right before contact all the energy/speed generated through rotation etc. goes into the arm and the body remains relatively still in this phase. If the body was still rotating, it would be very hard to keep the racket on track to hit the ball clean i think.
The same principle is at work with the one handed backhand for example where it is more obvious that the upper body stays relatively still (usually sideways) just before and after contact when you watch someone like Fed for example. On the forehand everything is so fast nowadays though that it causes a lot of confusion i think.
curious on johns thoughts.

cheers

It sure will be interesting in hearing Brian Gordon's take on this subject.

My perspective comes from that of a dumb tennis pro, so take it for what it's worth, but I definately tend to agree with this observation.


In a multi-segmented swing, the body rotates in segments, and at different speeds, from the ground up. And even though the hips, for instance, rotate forward much sooner than the shoulder and arm, they all "square up" (parallel to the baseline) at impact. (at least with stronger grips)

To me, this would suggest that the lower body, hips, , etc, start to slow there rate of rotation, to transfer energy to the last links. If they didn't , in the case of the hips, they would be grossely over-rotated at contact. And never achieve this almost universal "squared up" position

I think the "True Aligment" article by Kerry Mitchell, and his observation about the position of the hips, at impact is pertinant here.

[johnyandell]

These are reasonable hypotheses... I've got some 3D data Brian developed on Pete Sampras's serve. We'll start to ask some of those questions of it, starting with the speed of the racket.

[kiddy]

Todd Haydon serve

John

I thought the article on Todd's serve was very instructive, in particular the windmill drill I've found to be very effective for developing a btter a racquet drop.
I was wondering if you had any exercises or drills for developing forearm pronation into the ball during the hitting phase. Most of the drills I have involve trying to drive the ball into the ground which I have found to be a) not very effective and b) counter intuitive given the 'myth of the wrist snap'.

Any help advice would be greatly appreciated. Apologies if the answer is already somewhere in the site.
Kind regards

John

[johnyandell]

The best description of the upward swing to the ball is a "high five" with a service grip.

Technically "pronation" refers only to forearm rotation. But the upward swing is a rotation of the hand, entire arm and racket.

Often the term pronation is also used to describe the angle of the racket turning over in the followthrough. In my opinion the goal is not to create this position. It's an effect of the upward swing when the racket is well into the deceleration phase. Whatever the upward swing speed is, the racket will continue to turn over the appropriate amount in response.

I'm not a big believer in drills that are somehow different from the stroke motion itself. If you have a full racket drop, you can practice the high five by starting from the racket drop position. There is no big magic here. The elbow extends and the hand turns into the ball. The key is to video it and see if you make the positions. Without the video you never really know.
If it's good from the racket drop start, now video the whole motion.

All this is discussed several places. Check out the article on Pete's serve in Tour Strokes on the swing path and the various serve articles in Advanced Tennis on Fed and Roddick.

[crass_lawner]

Makes sense what you guys are saying. My thoughts are that in the kinetic chain the energy is always transferred from one part of the body to the next. Right before contact all the energy/speed generated through rotation etc. goes into the arm and the body remains relatively still in this phase. If the body was still rotating, it would be very hard to keep the racket on track to hit the ball clean i think.
The same principle is at work with the one handed backhand for example where it is more obvious that the upper body stays relatively still (usually sideways) just before and after contact when you watch someone like Fed for example. On the forehand everything is so fast nowadays though that it causes a lot of confusion i think.
curious on johns thoughts.

cheers

It sure will be interesting in hearing Brian Gordon's take on this subject.

My perspective comes from that of a dumb tennis pro, so take it for what it's worth, but I definately tend to agree with this observation.


In a multi-segmented swing, the body rotates in segments, and at different speeds, from the ground up. And even though the hips, for instance, rotate forward much sooner than the shoulder and arm, they all "square up" (parallel to the baseline) at impact. (at least with stronger grips)

To me, this would suggest that the lower body, hips, , etc, start to slow there rate of rotation, to transfer energy to the last links. If they didn't , in the case of the hips, they would be grossely over-rotated at contact. And never achieve this almost universal "squared up" position

I think the "True Aligment" article by Kerry Mitchell, and his observation about the position of the hips, at impact is pertinant here.

O.K. I said that I wasn't going to make anymore tennis related posts on this site, but I just can't help myself. Sorry John.

I agree 100% with Florian and 10s that energy is transferred from the ground up through the kinetic chain in chronological order, but I don't think it's true that each segment of the chain necessarily ceases to move after it has successfully transferred its energy to the next segment. I think that each segment transfers its energy once it has reached peak velocity, and after that it is transferring little or no energy, but it can't stop moving immediately due to inertia, so it continues to move (at a lower velocity) despite the fact that it is no longer transferring any energy.

If you watch a slo-mo video of Federer or Gonzales (or probably any pro) hitting a big forehand from a neutral stance you can really see their shoulders continue to rotate after contact has been made. This continuous movement does allow the player to maintain his balance though. But the key to the energy transfer is for the peak velocity (or acceleration - they'll occur at the same time) of each body segment to be reached in succession with the proper timing.

Of course the exact amount of body "follow though" will vary between styles, shots, and positions. In fact I can see Florian's point about the 1 handed backhand especially Federers. Sometimes, with low and/or wide balls, his body does in fact seem to reach peak velocity, transfer its energy to the arm, and then stop moving. Even his head stops moving and he's left staring at the contact point for a fraction of a second after the ball has left his racket. But even with Federer this isn't always the case, and on some backhands he really opens his shoulders up after contact. Henin and Gasquet both open their shoulders quite a bit after contact sometimes too.

[10splayer]

O.K. I said that I wasn't going to make anymore tennis related posts on this site, but I just can't help myself. Sorry John.

I agree 100% with Florian and 10s that energy is transferred from the ground up through the kinetic chain in chronological order, but I don't think it's true that each segment of the chain necessarily ceases to move after it has successfully transferred its energy to the next segment. I think that each segment transfers its energy once it has reached peak velocity, and after that it is transferring little or no energy, but it can't stop moving immediately due to inertia, so it continues to move (at a lower velocity) despite the fact that it is no longer transferring any energy.

If you watch a slo-mo video of Federer or Gonzales (or probably any pro) hitting a big forehand from a neutral stance you can really see their shoulders continue to rotate after contact has been made. This continuous movement does allow the player to maintain his balance though. But the key to the energy transfer is for the peak velocity (or acceleration - they'll occur at the same time) of each body segment to be reached in succession with the proper timing.

Of course the exact amount of body "follow though" will vary between styles, shots, and positions. In fact I can see Florian's point about the 1 handed backhand especially Federers. Sometimes, with low and/or wide balls, his body does in fact seem to reach peak velocity, transfer its energy to the arm, and then stop moving. Even his head stops moving and he's left staring at the contact point for a fraction of a second after the ball has left his racket. But even with Federer this isn't always the case, and on some backhands he really opens his shoulders up after contact. Henin and Gasquet both open their shoulders quite a bit after contact sometimes too.

Crass,
Yeah, I agree. If you read my post, I implied there was a slowing down of the preceding segment. At least that was my intent. I think a sudden halt would cause injury over a period of time, and I simply don't believe the body would allow that to happen. But then again, maybe I'm wrong.

[crass_lawner]

Crass,
Yeah, I agree. If you read my post, I implied there was a slowing down of the preceding segment. At least that was my intent. I think a sudden halt would cause injury over a period of time, and I simply don't believe the body would allow that to happen. But then again, maybe I'm wrong.

Yeah you're right, I misinterpreted what you meant by "square up." By square up you simply meant that the body parts are in alignment with each other and the baseline (assuming the ball was hit straight) for a brief moment which I agree with. I guess the part I was disagreeing with was the part in Florian's post where he said:

Right before contact all the energy/speed generated through rotation etc. goes into the arm and the body remains relatively still in this phase.

At least as it relates to the modern forehand. Like I said his quote does seem to apply to some types of backhands. But I can see how one might also think of it as still at contact in another sense, since at contact the body should also be the most balanced, and therefore have zero net forward, backward, or side to side motion. All the motion should be rotational, as opposed to when the player leans into the ball before contact or follows through, at which point his weight will be pulling backwards.

[10splayer]

Yeah you're right, I misinterpreted what you meant by "square up." By square up you simply meant are in alignment with each other and the baseline (assuming the ball was hit straight) for a brief moment which I agree with. I guess the part I was disagreeing with was the part in Florian's post where he said:



At least as it relates to the modern forehand. Like I said his quote does seem to apply to some types of backhands. But I can see how one might also think of it as still at contact in another sense, since at contact the body should also be the most balanced, and therefore have zero net forward, backward, or side to side motion. All the motion should be rotational, as opposed to when the player leans into the ball before contact or follows through, at which point his weight will be pulling backwards.

Yeah Crass,

It's all good! Your not the first person to misunderstand my writing.

[normand_trempe]

video request

Hello John! i have really enjoyed the article of Jose HIgueras called Learn to Play. And although you have a lot of articles on tactics and a lot of videos on strokes i think there could be more videos of point sequences (wich we could download) where you can see those tactics done by the best. I would love to be able to show my players where the pros recover after every shot for example, in a video of Fed where he hits 5 or 6 balls and where you seem how he plays the ball like Higueras says. Thank you very much and keep up the excellent work!

Tova

[johnyandell]

Yeah I agree. We are working on a new archive of point patterns with a wide camera set behind the court--sometime at the start of the year we'll probably start putting it up.

[llll]

john i am looking to but a video camera thats easy to download the video and then sent it for analysis. i cant find where you have specs to look for in a camera. can you tell where in the site i can find the info, thanks ,larry

[johnyandell]

http://www.tennisplayer.net/members/teaching_systems/john_yandell/using_tennisplayer_part2/using_tennisplayer_part2.html

[llll]

thanks john.

[tommyt]

Hey John, I was watching James Blake play recently and he was receiving a 2nd serve and up 15-30. He missed the return and subsequently lost the next 2 points handily and the game. He looked upset at himself at missing such an opportunity. It got me wondering how many players in Blake's situation, at 30 all after missing an easy 2nd serve opportunity, consequently lose the following 2 points and the game. I don't know if tennis has such stats. I always tell my students to reset after every point and a player like Nadal seems to be able to do that but I'm wondering about other players. Thanks.