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The Gorilla
05-18-2007, 12:49 PM
Which gives more power when you've time to set up, the open or the nuetral?

According to Vic Braden the linear momentum contributes to ''just'' 6mph... (bear with me please;) )

http://www.vicbraden.com/vics1.html#step

Which I think is quite a lot, we aren't told how fast each forehand is, but just to get an idea of the difference imagine if time henman's top serve jumped from 133mph to 139mph.

I think that would be very noticable, and he must know this, so why is knocking the nuetral stance?

This website...

http://coachesinfo.com/category/tennis/184/

(^^very intersting, well worth a look)

Goes into a biomechanical analysis of both stances

It finds that their is an increase in angular momentum peaking at the momet of impact with the nuetral stance ,(as opposed to the open stance which slows down before impact), and there is the added benefit of linear momentum with the nuetral stance,(that six mph).Overall a more powerful, higher velocity,(which means greater spin potential) stroke.

It also states that the closed stance is significantly more accurate.

Also, I find myself wondering if those giant leaps into the air by pros while using open stances are just the body trying desperately to move it's weight forward through the ball and get some linear momentum

and/or

an attempt not to fall to their left as all that left over angular momentum has to go somewhere, and without the left leg in front to absorb it and add to the linear momentum, (a possible increase to Braden's mph?) they would go careering to their left if their feet hadn't left the ground)

As all running forehands must be hit with a closed stance to prevent falling over, what is the benefit of the open stance?

This isn't a manifesto btw, this is a genuine question, I'd be very grateful if the people who really know what they're talking about,(no offence to anyone, I wouldn't include myself in that group), could explain this to me.

Slazenger
05-18-2007, 12:57 PM
From Vic's article
"Stepping into the ball just might get your center of gravity ahead of your front foot which will give you a faster first step towards the net than the player who faces the net and waits for the ball. But if you havenít been to the net since last April, stepping into the ball has very little value. "

LOL!

The Gorilla
05-18-2007, 01:02 PM
I think an added 6mph, no strings attached, is of value.

MordredSJT
05-18-2007, 01:15 PM
I think you are going into this with an incorrect assumption...that one stance is inherently "better" than the other. In my opinion they both have value and both should be used. If you watch professionals closely they will all use stances varying from closed to open and almost everything in between depending on what kind of ball they are hitting.

They are not jumping to control their angular momentum (the fact that they are in the air is a result of the large amounts of momentum they have created...they are being lifted off the ground, not jumping...a subtle but important difference). They are leaving the ground most often to help control their contact heights. If they didn't do this they would often be playing balls from well above shoulder level.

Watch a professional match with an eye totally on stances. You will almost certainly see that as the ball gets lower and closer to the middle of the court the stances will get progressively closed. As the ball gets higher and wider the stances will tend to open.

Slazenger
05-18-2007, 01:15 PM
I think an added 6mph, no strings attached, is of value.

I agree. I step into the ball whenever it's possible and sometimes I force the issue and step in even when i'm squeezed.
For me it's all about accuracy and I am more accurate when I step into my shot than hitting open stance.

The Gorilla
05-18-2007, 02:01 PM
I think you are going into this with an incorrect assumption...that one stance is inherently "better" than the other.

I really amn't.


In my opinion they both have value and both should be used. If you watch professionals closely they will all use stances varying from closed to open and almost everything in between depending on what kind of ball they are hitting.

my question is when is the open stance the better shot taking into account all the info that biomechanical study unearthed.

They are not jumping to control their angular momentum (the fact that they are in the air is a result of the large amounts of momentum they have created...they are being lifted off the ground, not jumping...a subtle but important difference). They are leaving the ground most often to help control their contact heights.If they didn't do this they would often be playing balls from well above shoulder level.



I never said they were jumping, I said maybe that's where the wasted momentum is going, (the study shows angular momentum slows down as the racquet nears the ball, resulting in slower velocity).



Watch a professional match with an eye totally on stances. You will almost certainly see that as the ball gets lower and closer to the middle of the court the stances will get progressively closed. As the ball gets higher and wider the stances will tend to open.

Well, if the balls are in the middle of the court they will have to step in won't they?

I'm not being rude but I think you have missed the point of my question, based on the info the study I have cited when is it advantagous to hit with an open stance seeing as it is (a)less powerfull and (b)less accurate.

MordredSJT
05-18-2007, 04:34 PM
I'm not being rude but I think you have missed the point of my question, based on the info the study I have cited when is it advantagous to hit with an open stance seeing as it is (a)less powerfull and (b)less accurate.

I don't think that you can categorically state that hitting with an open stance is always less powerful and less accurate. However, I believe you missed the obvious answers to your question in my post. Using an open stance is advantageous on high bouncing balls because it allows the player to more easily elevate in order to control the contact height. It is also more advantageous to some degree on wide balls because it both allows a larger degree of torso rotation and quicker recovery.

The Gorilla
05-18-2007, 05:37 PM
if you aren't going to read the biomechanical studie's findings then it is pointless talking to you.This is why I was hoping people who know what they're talking about could help me out on this.

MordredSJT
05-18-2007, 07:39 PM
I take your simple refusal to acknowledge my points to mean that you have no satisfactory response.

I teach tennis for a living. I hold degrees in physics and computer science. I read your links. If you think that I am mistaken or unqualified then kindly respond to the substance of my posts.

The first link that you have given presents information that isn't really all that new or revolutionary. If you have more forward momentum in combination with a stroke that is mechanically similar to your regular stroke you will hit the ball harder. The second link you give is information from 1999. It isn't necessarily bad information, but I fail to see how you come to your conclusion...which seems to be that the closed stance is always better. The information that I have seen has always shown that open and closed stance forehands vary by amounts which are often statistically insignificant or just enough to make a difference that is marginal at best.

The advantages of the closed stance are slightly more pace and a slightly larger hitting window. The advantages of the open stance are slightly faster recovery time, increased ability to elevate in order to control contact height, and increased torso rotation. Notice I did not say anything about the speed of the rotation which is practically equivalent between the two, though the acceleration profiles appear to be different. I'm speaking of the degree of rotation.

So...if you can step into a ball with a closed or neutral stance, with your weight on your front foot, elevate up to two feet in the air in order to contact the ball at a height lower than your shoulder, rotate your shoulders up to 180 degrees, land on balance, and recover quickly to an ideal position on the court...you don't need an open stance. It would be a neat trick. I don't think I've ever seen a human being that could pull it off.

The truth is that most professionals will step into a ball to some extent or another if given the chance. The thing is that they are not given that chance all the time because they are playing another very good tennis player! Sometimes they have to trade the advantages of the closed stance for the advantages of the open stance (which I stated above). The best players use both at the appropriate times. From your own link, "Elite players make a living on minute differences that less-skilled players have difficulty duplicating." This goes both ways!

You said this was not a manifesto but a genuine question. Do you feel like giving a genuine response and having a dialog? Or will you simply brush off my points again?

P.S. I've hit running forehands with an open stance...and not fallen over :)

JohnYandell
05-18-2007, 08:25 PM
We need more studies, a lot more studies, by people like Duane Knudsen that actually measure things like these differences in the stances

However, a few facts that Duane states himself as the conditions of his study are quite important to note.

First, the subjects all hit with the same unfamiliar racket. They were teaching pros and 3.5 to 4.5 players. Second, they hit 5 balls with each stance and only the fastest one was analyzed. Third, there was no technical description of grip or swing style. Foruth the ball was projected from a machine and there is no mention of the contact height.

Even Duane was very circumspect in his conclusions--the differences were so small as to be questionable. he didn't go so far as to conclude there was some clear superiority, at least as demonstrated in his study.

If we look at the grips on most pro forehands, they are so extreme that a netural stance blocks the natural rotation of the body. The rotation associated with these forehands is 180 degrees plus. While you can certainly step in a rotate less with a less extreme grip--something applicable for most all recreational players, at the pro level, even the guys with more conservative girps like Roger are rotating the torso like crazy.

They do this either from open stance, or rotating the foot off with the neutral.

Contact height in the pro game dictates grip and stance to a great extent. But it can't be a coincidence that the players rotate their bodies, as well as there hands and arms, so much more on so many more balls.

Speed is up. Spin is up compared to a few years ago. Myabe if every pro was superman and could step into every ball and hit on the rise they would hit harder, but I think there just isn't any actual data. And I doubt it. The forces created by all that rotation are very substantial in my opinion.

The Gorilla
05-19-2007, 05:46 AM
We need more studies, a lot more studies, by people like Duane Knudsen that actually measure things like these differences in the stances

However, a few facts that Duane states himself as the conditions of his study are quite important to note.

First, the subjects all hit with the same unfamiliar racket. They were teaching pros and 3.5 to 4.5 players. Second, they hit 5 balls with each stance and only the fastest one was analyzed. Third, there was no technical description of grip or swing style. Foruth the ball was projected from a machine and there is no mention of the contact height.

Even Duane was very circumspect in his conclusions--the differences were so small as to be questionable. he didn't go so far as to conclude there was some clear superiority, at least as demonstrated in his study.

If we look at the grips on most pro forehands, they are so extreme that a netural stance blocks the natural rotation of the body. The rotation associated with these forehands is 180 degrees plus. While you can certainly step in a rotate less with a less extreme grip--something applicable for most all recreational players, at the pro level, even the guys with more conservative girps like Roger are rotating the torso like crazy.

They do this either from open stance, or rotating the foot off with the neutral.

Contact height in the pro game dictates grip and stance to a great extent. But it can't be a coincidence that the players rotate their bodies, as well as there hands and arms, so much more on so many more balls.

Speed is up. Spin is up compared to a few years ago. Myabe if every pro was superman and could step into every ball and hit on the rise they would hit harder, but I think there just isn't any actual data. And I doubt it. The forces created by all that rotation are very substantial in my opinion.



thanks .

BrianGordon
05-19-2007, 03:56 PM
Speed is up. Spin is up compared to a few years ago. Myabe if every pro was superman and could step into every ball and hit on the rise they would hit harder, but I think there just isn't any actual data. And I doubt it. The forces created by all that rotation are very substantial in my opinion.

Maybe not on pros - but there is plenty of data to fully explain the mechanics of any stance manifestation in brutal detail - why do I have a feeling that will happen in your tennis universe!

JohnYandell
05-19-2007, 11:37 PM
So give it up! Or wait, is this going to be our next multiple part article series on Tennisplayer?

Any other published work on this besides Duane's? It's just hard to draw many real conclusions from it, as he is the first to say.