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-   -   Your Contact Point for Topspin Groundstrokes (http://tt.tennis-warehouse.com/showthread.php?t=463128)

PhilStar! 05-09-2013 06:34 PM

Your Contact Point for Topspin Groundstrokes
 
Where is your initial contact point when you hit your topspin forehand groundstrokes?

This video on Caroline Wozniacki shows 3 contact point:

http://www.youtube.com/watch?v=RGt2tqXerJ0

1. sweetspot ( middle of the racquet )
2. above the center mains of the strings
3. below the center mains of the strings

There's all different type of opinions regarding where a player should hit but a popular theory is that if the contact point is at the sweetspot or below it, there's less room to brush and therefore, a likelihood that you could end up framing the ball.

Then there's famed guru, Oscar Wegner, who says that most pros actually hits the ball well below the center of the racquet:

http://www.youtube.com/watch?v=MxUPDHegz98


So where do you folks make initial contact for your topspin strokes?

( this is probably the spot of the racquet that you'll likely end up breaking the strings at too ).

Just trying to get an idea where majority of the people make contact for their topspin here.

Bartelby 05-09-2013 06:37 PM

Contact point usually means how far in front you hit.

PhilStar! 05-09-2013 06:45 PM

I meant contact point for where the ball makes contact on the racquet face ....

rkelley 05-09-2013 07:08 PM

I just go for the center of the racquet. It's hard enough to hit that as it is. If I want more topspin then I direct my swing path to be more vertical.

LeeD 05-09-2013 07:45 PM

I think some exceptional pros can hit higher on the racket to impart a shorter spinnier ball, or lower on the racket to hit a more solid shot, but it's more by instinct than cerebral.

WildVolley 05-09-2013 07:46 PM

The frame!:twisted:

Actually, I'd guess most people don't know as this isn't the sort of thing you can easily see. I need high speed video to see, unless I notice strong twisting in my hand.

S&V Specialist 05-09-2013 07:51 PM

Heavy top/side spin shots: above
Penetrating pace: below

sureshs 05-09-2013 07:59 PM

If I want to hit high loopy topspin on a low ball, I end up hitting below the sweetspot. It just happens by itself.

A lot of it is determined by whether the ball is rising or falling, and how closed/open your racket face is, and the height of the ball. You can argue that a lower point helps in pulling up the ball more for top spin, or that (as in a previous post) that you would increase the chances of missing it, or it can be argued that the intended contact point is above or below what was actually observed, etc.

PhilStar! 05-09-2013 08:00 PM

Quote:

Originally Posted by WildVolley (Post 7399954)
The frame!:twisted:

Actually, I'd guess most people don't know as this isn't the sort of thing you can easily see. I need high speed video to see, unless I notice strong twisting in my hand.

But typically, it's usually where the string breaks (unless you're mixing in flat shots) as an indicator where you usually hit the ball.

Also, a player can be conscience as to where they're aiming the racquet face at when they're about to make contact.

I tend to hit more above the center mains ( as shown in the 2nd stroke of the Wozniacki clip ) but the frame does open up and the ball tends to go loopy afterward. Aiming it above the sweetspot gives me a higher margin for error so even if I miss that part of the racquet, the sweetspot will still get the ball. I've never framed the ball this way.

I am curious however how players hit well below the center yet doesn't frame it, because the margin for error is so low.

sureshs 05-09-2013 08:01 PM

Quote:

Originally Posted by rkelley (Post 7399881)
I just go for the center of the racquet. It's hard enough to hit that as it is. If I want more topspin then I direct my swing path to be more vertical.

Probably that is what the pros do. We see slightly different results based on the situation, and may end up thinking that was the intent.

10isfreak 05-10-2013 07:48 AM

Quote:

Originally Posted by rkelley (Post 7399881)
If I want more topspin then I direct my swing path to be more vertical.

Not that this is false, but your swing path has a greater influence on the ball's flying increment than on its spin.

If you want more spin, without changing anything else, close your racket face a bit. The idea is that you'll get to make contact above the center of the ball with a closed face, meaning that the upper edge will get accelerated forward. As you swing a lot faster forward than upward -- I've rarely seen pros going beyond 30 degrees of swing path prior contact, including Nadal on clay -- you'll get more spin that way.

rkelley 05-10-2013 07:54 AM

Quote:

Originally Posted by 10isfreak (Post 7401204)
Not that this is false, but your swing path has a greater influence on the ball's flying increment than on its spin.

If you want more spin, without changing anything else, close your racket face a bit. The idea is that you'll get to make contact above the center of the ball with a closed face, meaning that the upper edge will get accelerated forward. As you swing a lot faster forward than upward -- I've rarely seen pros going beyond 30 degrees of swing path prior contact, including Nadal on clay -- you'll get more spin that way.

I do not agree. If you close your racquet face without changing anything else you'll just hit the ball lower over the net, or perhaps into the net. This is my experience as a player, and also what I would deduce from physics (I have an Masters in Mechanical Engineering).

If you want more topspin you need a greater vertical component in your swing. Open or close the racquet face to get the appropriate height over the net.

WildVolley 05-10-2013 07:59 AM

Quote:

Originally Posted by PhilStar! (Post 7399979)
But typically, it's usually where the string breaks (unless you're mixing in flat shots) as an indicator where you usually hit the ball.

Also, a player can be conscience as to where they're aiming the racquet face at when they're about to make contact.

Usually, my string breaks high center of the racket head, which is where I hit most balls.

However, I don't think that tells us much of what you want to know. The original video shows hits high or low around the axis running through the handle and up the head. Since I don't always hold the racket with the same face forward, the shots are going to be distributed around that center line, even if I'm consistently hitting in the stringbed closer to the ground or above that line toward the sky.

If you're hitting high in the stringbed (while the face is horizontal) isn't the racket trying to torque open on most shots? That would get annoying quickly.

mightyrick 05-10-2013 08:03 AM

I hit a pretty heavy ball, but I really only know what it feels like. To get more or less topspin, I know how to adjust the "feel" of the stroke.

It makes me feel like an idiot to hear you guys are able to tell yourself to contact a couple inches higher or lower on the stringbed, or adjust the face five degrees. Man, I don't know how you guys are able to think and position and detect where you hit so precisely when things move so quickly.

10isfreak 05-10-2013 08:07 AM

Quote:

Originally Posted by sureshs (Post 7399983)
Probably that is what the pros do. We see slightly different results based on the situation, and may end up thinking that was the intent.

The vast majority of my strokes end closer to the bottom edge, not in the dead center of the racket. It's not really something I think about, it's more something that simply happens. The stringers I talked to also noticed it. The near-edges are filled with fuzz and worn out when advanced players bring their racket.

I am sure if you watch a pro hitting many balls in super slow-motion, you'll pick it up: unless he hits flat, he'll almost always make a low contact.

With that said, you shouldn't be thinking about this. If anything, it will become an habit by trial and error, through practice and time. There are other details that are more important, I would say.

WildVolley 05-10-2013 08:17 AM

Quote:

Originally Posted by mightyrick (Post 7401297)
It makes me feel like an idiot to hear you guys are able to tell yourself to contact a couple inches higher or lower on the stringbed, or adjust the face five degrees. Man, I don't know how you guys are able to think and position and detect where you hit so precisely when things move so quickly.

You're obviously not a very good tennis player if you can't see whether you hit the ball an inch below or above the center line.:twisted:

As I suggested, the only way I can tell is by using high speed video. And even with the setup, I don't video many of my practices. Mostly I just use the video when I'm working on something new or I have someone to shoot for me. At 240 frames a second, that video card gets filled up fast.

sureshs 05-10-2013 08:23 AM

Quote:

Originally Posted by 10isfreak (Post 7401317)
The vast majority of my strokes end closer to the bottom edge, not in the dead center of the racket. It's not really something I think about, it's more something that simply happens. The stringers I talked to also noticed it. The near-edges are filled with fuzz and worn out when advanced players bring their racket.

I am sure if you watch a pro hitting many balls in super slow-motion, you'll pick it up: unless he hits flat, he'll almost always make a low contact.

With that said, you shouldn't be thinking about this. If anything, it will become an habit by trial and error, through practice and time. There are other details that are more important, I would say.

Bottom edge is natural with closed face top spin. It just happens naturally. So I would think.

But we had discussed this before in great detail. Hundreds of videos were studied, and the impact point was all over, not necessarily below. But the issue was never resolved because 1. There was a requirement that only TS balls should be counted (slices are supposedly hit on the upper side - that was the claim), and flat shots also were supposed to be discounted. Who gets to judge that decisively from a few seconds of video? 2. The results were challenged on the basis that the intention of the pro was to hit lower but he couldn't (on the clips which did not support the hypothesis). Who can decide that? 3. It was also claimed by the opposers that shots which were impacted below actually might have slid down because of deformation and gravity, and the impact was higher.

Just to tell you that this is an old topic beaten to death without conclusion.

Chas Tennis 05-10-2013 08:47 AM

Some earlier replies on where on the racket face the ball is first contacted:

Quote:

Originally Posted by toly (Post 7136064)
I think you are right and thank you for post #192.

Below is set of pictures that show point of contact. They copied from random samplings of following high speed videos:

1. Federer Inside Out Forehand tennisplayer.net https://www.youtube.com/watch?v=z6LmJyNoL8U
2. Sharapova Inside Out Forehand1 http://www.youtube.com/watch?v=uC254i1XN9I
3. AO 2012 Sharapova Easy Short Ball Forehand Winner http://www.youtube.com/watch?v=n9egjkaBnYg
4. AO 2012 Kvitova Forehand Return Serve Winner http://www.youtube.com/watch?v=Bnezy_gBxpY
5. AO 2012 Kvitova Second Serve Return Forehand http://www.youtube.com/watch?v=Z8xrhvDIE50
6. AO 2012 Nadal Down the Line Running Forehand http://www.youtube.com/watch?v=594rg_Lrcjw
7. AO 2012 Djokovic Baseline Forehand http://www.youtube.com/watch?v=f5jWEzDsxWg
8. AO 2012 Djokovic Short Ball Forehand http://www.youtube.com/watch?v=VrEwPvhT3lU
9. AO 2012 Djokovic Down the Line Backhand Winner http://www.youtube.com/watch?v=zlDsdMOXnHw
10. AO 2012 Djokovic First Serve Forehand Return Winner http://www.youtube.com/watch?v=eMECK-D9Dqk
11. Lleyton Hewitt Forehand http://www.youtube.com/watch?v=P4jgaPbHcZY
12. Davydenko Forehand http://youtu.be/hF4dlqFH_v8



IMO the best players don’t have tendency to hit ball below of the racquet longitude axis!!!

Quote:

Originally Posted by Chas Tennis (Post 7174656)
Stop Action with DVR. I looked at the clear high speed videos presented on the 2013 Australian Open by ESPN & Tennis Channel. I used my DVR to do stop action. Both ATP & WTA players. Only used videos that were clear with small motion blur. (Rejected double image effects probably due to unknown interlacing effects). Record keeping was poor, about 10-12 total.

These videos were usually winner highlights, where the players appeared to be in good position and intended to hit a very strong forehand. I don't believe that any were of shots that went out.

If the bottom/lowest frame edge of the racket were 0, the top/highest frame edge were 10 and the center line (handle center line extended) were 5 then

the ball hits were in the 4-6 range. I did not see any impacts that were way off the centerline.

Estimating impact spot, where 5 is the center line and the racket face is divided 0-10 bottom to top:
Li Na - 5, 6
Sharpova - 4, 5
Tipsaravic - 4
Some others also.....

I had intended to analyze more high speed videos shots just as Toly has done but have not gotten to it.

I had originally thought that pros deliberately or by trial-and-error practice were hitting most balls in the lower half of the racket face (say at 3 as defined above). Now I don't believe that. I intend to farther analyze videos for this issue as I come across them. The issue could be farther researched.

High Speed Video Analysis Issue- Racket is Rising Rapidly at Impact. One point is that for the current forehand with its rapid rise of the racket at impact, when you look at a high speed video and see ball impact, on the very next frame at 200-300 fps the racket will will have moved considerably higher. Not doing single frame analysis may produce a false conclusion as to where the ball was on the racket face at impact. Requires targeted high speed video with a clear view of the racket face, high frame rates >200 fps ?, a fast shutter speed for small motion blur, and observing ball impact on the strings. Any rolling of the ball on the strings makes analysis less accurate. Both the rapid racket motion up and the ball rolling on the strings might make the ball appear to initially hit low on the racket face if not carefully measured. I think that's what fooled me.

An interesting related question - Do I hit long and in the net because I am hitting high or low on the racket face - much more than the pros do - and the racket tilts while in contact?

This issue needs more work with high speed video that has adequate frame rates to see the ball movement during, say, 5 milliseconds of ball-string contact. 240 fps might not be enough. ?

PhilStar! 05-10-2013 11:14 AM

Quote:

Originally Posted by WildVolley (Post 7401269)

If you're hitting high in the stringbed (while the face is horizontal) isn't the racket trying to torque open on most shots? That would get annoying quickly.


It depends on how tight or loose I grip the racquet, and how fast and heavy the incoming ball is.

but in general, on average grip and incoming speed, it does torque and the racquet face do open up. The resulting shot is a loopy shot. However, I still impart tremendous spin on the ball.

Sometimes I tilt the racquet down while I swing and that helps a bit to keep the ball from going too loopy ( higher arc ).

PhilStar! 05-10-2013 11:15 AM

Quote:

Originally Posted by 10isfreak (Post 7401317)
The vast majority of my strokes end closer to the bottom edge, not in the dead center of the racket. It's not really something I think about, it's more something that simply happens. The stringers I talked to also noticed it. The near-edges are filled with fuzz and worn out when advanced players bring their racket.

I am sure if you watch a pro hitting many balls in super slow-motion, you'll pick it up: unless he hits flat, he'll almost always make a low contact.

With that said, you shouldn't be thinking about this. If anything, it will become an habit by trial and error, through practice and time. There are other details that are more important, I would say.

That's another good indicator I use as well; where all the fuzz is concentrated on the stringbed.


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