Interactive Forum: October 2012 - Juan Martin Del Potro Forehand

[bcousy14]

Good observations

To me, clearly, JMDP is hitting more through the ball on the inside/in and getting more below the ball for the inside out. I tried counting frames from where the racket head started to change direction at the bottom of his swing, but I couldn't get any clear difference. However, it does seem to me he is dropping much more below the ball on the inside/out shot. If we knew the actual angle of the shot, we could see how much court he had to work with. Perhaps he had to get the ball down quick over a higher net going inside out.

don

To speak to the varying depths of the racquet head in comparison to the ball, I believe it's more of a function of the height rather than the shot selection. When the ball is below the net and you want pace, you need the additional topspin to bring the upward trajectory of the ball back down. Having said that the selection of the shot/angle is also a factor because the sharper the angle the less court to work with after the ball crosses the net, hence the additional spin required. I mean one of my favorite shots is the HEAVY spin inside in fh back behind the opponent. So I don't think it's an inside in versus an inside out issue

[tennis_chiro]

Interesting point!

To speak to the varying depths of the racquet head in comparison to the ball, I believe it's more of a function of the height rather than the shot selection. When the ball is below the net and you want pace, you need the additional topspin to bring the upward trajectory of the ball back down. Having said that the selection of the shot/angle is also a factor because the sharper the angle the less court to work with after the ball crosses the net, hence the additional spin required. I mean one of my favorite shots is the HEAVY spin inside in fh back behind the opponent. So I don't think it's an inside in versus an inside out issue

You might have a point. It looks to me like the second, inside/out shot is lower, but not by more than about 6 inches. You do realize, that even at 80 mph, gravity drops Delpo's forehand almost 2 feet (1.75') by the time it gets to the net and he's going to have to hit up even on the high one. (Assuming 80mph forehand = 117 feet/sec, 40 feet to net and in 1/3 sec ball drops [32fps/s x 1/3 sec x 1/2]{avg speed of drop} x 1/3 sec= 1.78 feet). The length of the court he has to work with will be at least as significant as the 6" difference in the height of the ball. And gravity is dropping the ball significantly faster as the length of the shot increases.

don

[rstrecker]

Del Po FH

I see two things that help account for the heavier spin on the second shot in this sequence on JMDP's forehand.

First, if you concentrate on the tip of the racquet you can see that on the second, heavier spin shot, JMDP points the racquet tip almost straight down and then whips it upward. (Something others noted.) On the first ball, which is hit in a more flat trajectory, the tip never drops very far below the wrist. (The wrist has about the same relation to the ball on both shots to my eyes.)

The second difference, which is likely a direct consequence of the first, is that Juan uses a classic wiper finish on the second shot. On the second shot you can see the hitting face of the racquet during the follow until the almost the very end. On the flatter shot, the racquet tip points straight ahead very quickly after contact and you see the mainly the tip edge of the racquet during the follow through.

I have always thought that JMDP's left arm action on the forehand was a bit unusual in that he drops the left arm down rather than holding it parallel to the court which seems to be more typical of the modern high level forehand. Looking at the super slow motion here gives me a sense, for the first time, the JMDP uses this as a way of reinforcing the hitting arm loop and the knee bend. Very revealing.

[tennis_chiro]

Great point for comparison!

I see two things that help account for the heavier spin on the second shot in this sequence on JMDP's forehand.

First, if you concentrate on the tip of the racquet you can see that on the second, heavier spin shot, JMDP points the racquet tip almost straight down and then whips it upward. (Something others noted.) On the first ball, which is hit in a more flat trajectory, the tip never drops very far below the wrist. (The wrist has about the same relation to the ball on both shots to my eyes.)

The second difference, which is likely a direct consequence of the first, is that Juan uses a classic wiper finish on the second shot. On the second shot you can see the hitting face of the racquet during the follow until the almost the very end. On the flatter shot, the racquet tip points straight ahead very quickly after contact and you see the mainly the tip edge of the racquet during the follow through.

I have always thought that JMDP's left arm action on the forehand was a bit unusual in that he drops the left arm down rather than holding it parallel to the court which seems to be more typical of the modern high level forehand. Looking at the super slow motion here gives me a sense, for the first time, the JMDP uses this as a way of reinforcing the hitting arm loop and the knee bend. Very revealing.

The text I have highlighted here is a great point for comparison. When you look carefully, you can no longer see the stringbed side that hit the ball once DelPo's hand gets to the level of his chin in the first shot, but we never lose it in the second. The difference in the two shots is perhaps most clear at this concluding part of the stroke. Definitely hit more through the ball on the inside/in.

don

[stotty]

To see or not to see....

I see two things that help account for the heavier spin on the second shot in this sequence on JMDP's forehand.

First, if you concentrate on the tip of the racquet you can see that on the second, heavier spin shot, JMDP points the racquet tip almost straight down and then whips it upward. (Something others noted.) On the first ball, which is hit in a more flat trajectory, the tip never drops very far below the wrist. (The wrist has about the same relation to the ball on both shots to my eyes.)

The second difference, which is likely a direct consequence of the first, is that Juan uses a classic wiper finish on the second shot. On the second shot you can see the hitting face of the racquet during the follow until the almost the very end. On the flatter shot, the racquet tip points straight ahead very quickly after contact and you see the mainly the tip edge of the racquet during the follow through.

I have always thought that JMDP's left arm action on the forehand was a bit unusual in that he drops the left arm down rather than holding it parallel to the court which seems to be more typical of the modern high level forehand. Looking at the super slow motion here gives me a sense, for the first time, the JMDP uses this as a way of reinforcing the hitting arm loop and the knee bend. Very revealing.

Extremely interesting observations, especially that last paragraph.This is something I hadn't considered...DP's left arm, etc. Funny how I can study a clip for ages, think I've seen and noted everything, then it turns out I haven't.

You really ougth to drop in and post more often...

Love tennis_chiro's subsequent post, also...

[10splayer]

I see two things that help account for the heavier spin on the second shot in this sequence on JMDP's forehand.

First, if you concentrate on the tip of the racquet you can see that on the second, heavier spin shot, JMDP points the racquet tip almost straight down and then whips it upward. (Something others noted.) On the first ball, which is hit in a more flat trajectory, the tip never drops very far below the wrist. (The wrist has about the same relation to the ball on both shots to my eyes.)

The second difference, which is likely a direct consequence of the first, is that Juan uses a classic wiper finish on the second shot. On the second shot you can see the hitting face of the racquet during the follow until the almost the very end. On the flatter shot, the racquet tip points straight ahead very quickly after contact and you see the mainly the tip edge of the racquet during the follow through.

I have always thought that JMDP's left arm action on the forehand was a bit unusual in that he drops the left arm down rather than holding it parallel to the court which seems to be more typical of the modern high level forehand. Looking at the super slow motion here gives me a sense, for the first time, the JMDP uses this as a way of reinforcing the hitting arm loop and the knee bend. Very revealing.

This observation is one of the defining characteristics of the modern forehand (imo).....The real difference in swing geometry (between now and past) is how players use the wiping action to create (proportionally) more spin....And the ramifications are significant.

When i was growing up, the wiping action, or arm rotation, was, if anyting, discouraged. Topspin was primarily a function of path, i.e. more topspin=steeper path....of course this big down to up move came at the expense of ball speed....which is totally unacceptable in the modern game..

What i see happening, is players swinging on a much shallower path and allowing the racquet head to rotate under, in vary degrees, to generate more or less topspin. So in essence, they are getting the best of both worlds....The shallow path creates incredible "plow through" abilities (ball speed) while the amount of hand and arm rotation regulates (a large proportion) of topspin production.

Of course, there are infinate ways to combine path (shallow vs steep) and arm arm rotation/wiping rates, but,, if you want to get an idea of how much topspin a player is trying to produce on any given shot, look at the relationship between the hand and the tip of the racquet at the beginning of the forward swing..

[julian1]

Shallow?

This observation is one of the defining characteristics of the modern forehand (imo).....The real difference in swing geometry (between now and past) is how players use the wiping action to create (proportionally) more spin....And the ramifications are significant.

When i was growing up, the wiping action, or arm rotation, was, if anyting, discouraged. Topspin was primarily a function of path, i.e. more topspin=steeper path....of course this big down to up move came at the expense of ball speed....which is totally unacceptable in the modern game..

What i see happening, is players swinging on a much shallower path and allowing the racquet head to rotate under, in vary degrees, to generate more or less topspin. So in essence, they are getting the best of both worlds....The shallow path creates incredible "plow through" abilities (ball speed) while the amount of hand and arm rotation regulates (a large proportion) of topspin production.

Of course, there are infinate ways to combine path (shallow vs steep) and arm arm rotation/wiping rates, but,, if you want to get an idea of how much topspin a player is trying to produce on any given shot, look at the relationship between the hand and the tip of the racquet at the beginning of the forward swing..

Just trying to understand your terminology.
Is the path in the link below shallow?

http://www.youtube.com/watch?v=lPBM-hE1Dhw

[10splayer]

Just trying to understand your terminology.
Is the path in the link below shallow?
http://www.youtube.com/watch?v=lPBM-hE1Dhw

The "path" would be, how much the the shoulder lifts the arm out to the ball. The "steepness" of the swing....What I'm saying is that in days past, a guy like Borg would swing the racquet upward on a much steeper plane..I've seen numbers in the ball park of an upward 45 to 55 degree slope on an average rally shot. If you contrast that with a guy like Fed (who on average) is only swinging upwards at about 30 degrees.

Now, here's the thing JUlien, if Fed is only swing up at 30 degrees or so, how does one account for the tremendous spin that he creates? The answer in my mind, is the much more pronounced windshield wiping action...this adds more spin regardless of how steep or shallow the arm movement is..an independent variable as it were.

If you isolate the hand path in the del potro videos, I see not much difference..What is different is the position of the racquet tip at the beginning of the forward swing.....The tip is much more "underneath" the hand with the heavier spin shot..

As i mentioned earlier, the player gets the best of both worlds. Because the swing is shallower, they can still retain a lot of ball speed and yet create a tremedous amount of spin with the wiper action..which is why we are seeing laser like, 90 mile balls with upwards of 3000 rpms of spin..

Just my 02 cents.

[don_budge]

Strings and things...?

The "path" would be, how much the the shoulder lifts the arm out to the ball. The "steepness" of the swing....What I'm saying is that in days past, a guy like Borg would swing the racquet upward on a much steeper plane..I've seen numbers in the ball park of an upward 45 to 55 degree slope on an average rally shot. If you contrast that with a guy like Fed (who on average) is only swinging upwards at about 30 degrees.

Now, here's the thing JUlien, if Fed is only swing up at 30 degrees or so, how does one account for the tremendous spin that he creates? The answer in my mind, is the much more pronounced windshield wiping action...this adds more spin regardless of how steep or shallow the arm movement is..an independent variable as it were.

If you isolate the hand path in the del potro videos, I see not much difference..What is different is the position of the racquet tip at the beginning of the forward swing.....The tip is much more "underneath" the hand with the heavier spin shot..

As i mentioned earlier, the player gets the best of both worlds. Because the swing is shallower, they can still retain a lot of ball speed and yet create a tremedous amount of spin with the wiper action..which is why we are seeing laser like, 90 mile balls with upwards of 3000 rpms of spin..

Just my 02 cents.

Very interesting...but I fail to see how the wiper action by itself can account for an increase in spin unless somehow it is related to the equipment and the strings. For example...I doubt that even the Fed with his wiper action forehand would get the big increase in spin using Borg's racquet and strings. He may produce less spin. Is the increase in spin a factor of equipment and strings?

Come to think of it...that might make for an interesting experiment.

[10splayer]

Very interesting...but I fail to see how the wiper action by itself can account for an increase in spin unless somehow it is related to the equipment and the strings. For example...I doubt that even the Fed with his wiper action forehand would get the big increase in spin using Borg's racquet and strings. He may produce less spin. Is the increase in spin a factor of equipment and strings?

Come to think of it...that might make for an interesting experiment.

Certainly not discounting equipment in the equation. Having said that, I would bet a lot of money that Fed could go out there and achieve ball speeds and spin rates much greater than Borg ever could with the same equipment.
No, I think this is technique oriented.

DB, look at the Del Po video again, and tell me what you see. The real difference as i see it is the position of the racquet tip at the beginning of the forward swing. With the higher spin shot, the forearm is much more supinated and racquet shaft is oriented downward. Can you see how this would lead to more topspin?

[10splayer]

Actually just skimmed over the Gordon article again. (i thought he touched on this a bit) Anyway, I think Brian is saying the same thing when he talks about how the "amount of flip determines the counter rotations and orientation of the shaft as the swing progresses forward. The variations in the amount of flip is critical in controlling the amount of spin on any given shot".


The real significance (to me) is that a player need not take a huge uppercut at teh ball to create a high spin rate.

[don_budge]

Ball position?

Can you see how this would lead to more topspin?

Of course...especially if he is hitting the ball "further forward in his stance" to borrow from golf terminology as I referred to his golfing the ball in my post earlier in the thread. Even if he is only hitting the ball two ball positions earlier in the second swing the angle of impact is going to be significant.

It is hard to tell if he is meeting the ball earlier and by how much but to my eye it appears that he is and for me that would account for the increase in spin rate. Ball position relative to the upward trajectory of his swing.

[10splayer]

Of course...especially if he is hitting the ball "further forward in his stance" to borrow from golf terminology as I referred to his golfing the ball in my post earlier in the thread. Even if he is only hitting the ball two ball positions earlier in the second swing the angle of impact is going to be significant.

It is hard to tell if he is meeting the ball earlier and by how much but to my eye it appears that he is and for me that would account for the increase in spin rate. Ball position relative to the upward trajectory of his swing.

A much bigger "player" in production of topspin, is the counter rotation of the arm in the forward swing (how much).....In the higher spin shot, the shaft of the racquet is pointed much more downward. To achieve more or less a shaft parallel position at impact, the racquet head would have to be rotated up more than on the lower spin shot...more spin. In fact, i think that's the most distinguishing difference in the 2 DEL PO examples....

[julian1]

Two components

The "path" would be, how much the the shoulder lifts the arm out to the ball. The "steepness" of the swing....What I'm saying is that in days past, a guy like Borg would swing the racquet upward on a much steeper plane..I've seen numbers in the ball park of an upward 45 to 55 degree slope on an average rally shot. If you contrast that with a guy like Fed (who on average) is only swinging upwards at about 30 degrees.

Now, here's the thing JUlien, if Fed is only swing up at 30 degrees or so, how does one account for the tremendous spin that he creates? The answer in my mind, is the much more pronounced windshield wiping action...this adds more spin regardless of how steep or shallow the arm movement is..an independent variable as it were.

If you isolate the hand path in the del potro videos, I see not much difference..What is different is the position of the racquet tip at the beginning of the forward swing.....The tip is much more "underneath" the hand with the heavier spin shot..

As i mentioned earlier, the player gets the best of both worlds. Because the swing is shallower, they can still retain a lot of ball speed and yet create a tremedous amount of spin with the wiper action..which is why we are seeing laser like, 90 mile balls with upwards of 3000 rpms of spin..

Just my 02 cents.

I really do NOT understand your original post plus the follow-up exchange
There are TWO components
in

http://www.youtube.com/watch?v=lPBM-hE1Dhw

Both of them contribute to spin
The flip before 0:08/0:12 is "THE QUICK/DEEPER" component
The continuation AFTER is a "SHALLOWER" component
Please let me me know whether this post of mine is clear
Julian
PS I have a British spelling of my first name.
PS MY clip is about backhand but it does NOT matter

[10splayer]

There are TWO components
in

http://www.youtube.com/watch?v=lPBM-hE1Dhw

Both of them contribute to spin

Please explain