The Forehand: Busting misconceptions once and for all

[sureshs]

Originally Posted by dominikk1985

Do you think that those guys intentionally hit the ball below the center?

And sometimes it may not be desired - i.e. it may be a mishit which we think had a purpose which it did not have

[corners]

Originally Posted by dominikk1985

the racket tilt is more to push a rising ball (early striking) down to flatten the path of the ball (since a rising ball tends to continue to rise after hitting the stringbed) not so much to create spin.

watch the same player hitting the ball on the drop and he will hit with the same spin but a vertical racket face. the other reason for the racket tilt is that the ball is below the racket center when it leaves the stringbed (not at the moment of initial strike as the tennisspeed guy claims!) because the stringbed brushes upwards. this causes the racket to tilt.

You're correct that the closed racquet faces we see on the forehand in the pro game are primarily a response to counter balls on the rise. But closing the racquet face is also effective, and sometimes a requirement, to counter incoming balls with heavy topspin. If you hit a ball with heavy topspin at a wall the ball will bounce "up" off the wall. The same thing happens when a heavy topspinning ball bounces off a stringbed. Closing the racquet face also lowers the bounce trajectory when returning heavily spun balls.

I think with his opinion that the racket tilt increases spin the tennisspeed guy is pretty much alone.

Closing the racquet face unquestionably increases topspin, and will produce topspin even with a completely horizontal swingpath.

You can illustrate this using TW University's shot simulator.

[LeeD]

What is "correct"?
EvonneGoolagong often hit forehand with an open face.
DavidFerrer seldom.

[corners]

Originally Posted by dominikk1985

Do you think that those guys intentionally hit the ball below the center?

John Yandell did a study of video of Fed, Nadal and Djoker and found that all three players hit 1-2 inches outside the center of the strings far more often than they hit the center of the strings. They tended to miss the center toward the tip of the racquet most often. There was nothing in his data to suggest that they strike below center more often than anywhere else.

[Chas Tennis]

Racket oriented news story -
http://www.nytimes.com/2012/08/27/sp...game.html?_r=0

Some articles with older references, latest references about 2002 or so. Forehands have changed.

1) Knudson & Elliott chapter, starts on page 150?
http://books.google.com/books?id=ZLh...20face&f=false

2) http://www.coachesinfo.com/index.php...les&Itemid=173

3) http://www.coachesinfo.com/index.php...les&Itemid=173

Videos of ball impacts
http://www.youtube.com/watch?v=O2wMPW_ivBo
http://www.youtube.com/user/ITFTechnical/videos
http://www.youtube.com/watch?v=tNUBmOt2gOU

Spaghetti strings
http://engineeringsport.co.uk/2010/0...hetti-strings/

[corners]

Originally Posted by 10isfreak

There is a direct relationship between spin production and how low the ball makes contact with the string bed. The racket is nearly horizontal during ground strokes, so low actually means near the side which is closest to the ground, not near the throat -- just to clear up the potential confusion. A low contact ensures the highest spin/pace ratio (that is, you get more spin, less pace this way).

This was the finding of the TW Professor in this study: http://twu.tennis-warehouse.com/lear...r/location.php

Balls that impact either above or below center will rebound about 9 miles per hour slower than one that impacts dead-center, and the above study found that balls impacting below center (toward the ground) will bounce off with about 35% more spin than those hitting dead-center and about 60% more spin than those hitting above center (toward the sky). So missing the sweetspot has pretty big implications for shot speed, spin and accuracy.

[sureshs]

Remember that the ball also slides along the strings during the dwell time, especially with the low tensions of the pros, so there may not be just a single area of contact.

[tennisfan69]

Suresh, do pros use low tension? any idea for tension ranges? thanks for the info.

[sureshs]

Originally Posted by tennisfan69

Suresh, do pros use low tension? any idea for tension ranges? thanks for the info.

I am reading that pros are doing 40s these days. This is what the latest issue of RSI mag says. Of course, they restring every day so that is their real tension (max loss is within 24 hours). On the other hand, I think Nadal was still in the 50s.

I would suggest you post in the rackets or strings section and see if drakulie answers. He is a pro stringer.

[Off The Wall]

Originally Posted by corners

John Yandell did a study of video of Fed, Nadal and Djoker and found that all three players ... tended to miss the center toward the tip of the racquet most often.

This is not by accident. Advanced players prefer to hit there.

[luvforty]

Originally Posted by Off The Wall

This is not by accident. Advanced players prefer to hit there.

yeah, certainly doesn't need a 'study' for this..... it's pretty straight forward 7th grade physics stuff

[10isfreak]

Originally Posted by sureshs

Remember that the ball also slides along the strings during the dwell time, especially with the low tensions of the pros, so there may not be just a single area of contact.

The contact lasts less than a fifth of a blink of an eye... that is, about 0,004 or 0,005 seconds. The ball doesn't even slide a millimeter, let alone spinning due to sliding.

[luvforty]

Originally Posted by 10isfreak

The contact lasts less than a fifth of a blink of an eye... that is, about 0,004 or 0,005 seconds. The ball doesn't even slide a millimeter, let alone spinning due to sliding.

huh? what makes that hissing sound when you hit a spin serve, or when you cut a heavy slice? (if you have experienced either)

[10isfreak]

Originally Posted by toly

Yes, nothing can happen instantaneously. But, let’s assume that incoming ball has 2000rpm topspin and Nadal hits TS FH with 5000rpm. Is it possible? Yes, he did it many times.

So, during dwell time he eliminates incoming ball 2000rpm spin and creates his own opposite 5000rpm topspin. This transformation is done mostly by using friction between strings and ball.

Thus, 0.002-0.005sec is more than enough to just stop ball’s rotation.

Actually, your inference is not justified. One, the racket is not standing on a table... it is moving -- there is kinetic energy transferred from the racket, to the ball. Nothing whatsoever implies that friction alone is responsible for spin variation, much rather, you have TONS of directed energy to negate the effects of spin.

Also, spin reduces through the air and at ground contact... which are both a lot longer and a lot more annoying to me that barely touching strings which aren't nearly as sticky as a tennis court.

[10isfreak]

Originally Posted by dominikk1985

Do you think that those guys intentionally hit the ball below the center?

My psychology teacher resumed the value of science in a few words. He said that psychology, as any scientific field, empowers its user with regard to some object of study. In that case, it grants the user power over himself and others.

In science, we do not happen to find stuff out of sheer luck... we devise systematic experiments to try and avoid the inefficiency of trials and errors. Knowing what to do because of science is being smart; knowing what to do out of personal experience is sheer luck.

Experience drives you depending on various factors which you do not control... they may drive you to do exactly what is required in one situation or even many situations, but it all depends on how coherent the sample that constitute your experience is with reality as a whole. (Your life is effectively a sample of a population which regroups the experience of everyone, as well as experiences that could have occurred, but didn't)

If your experience fits the bill, you do not succeed out of genius or because you are smart... you simply were lucky, like the guy who earned his fortune with a lottery ticket.


The only way to be intentionally succeeding is to build knowledge and use it. It's also one of the very few things that should separate adults from children who do not have the biological luxury of being capable of formal reasoning, which includes the deductive reasoning which is required to find concrete applications to abstract ideas such as scientific theories.

[bad_call]

Originally Posted by 10isfreak

My psychology teacher resumed the value of science in a few words. He said that psychology, as any scientific field, empowers its user with regard to some object of study. In that case, it grants the user power over himself and others.

In science, we do not happen to find stuff out of sheer luck... we devise systematic experiments to try and avoid the inefficiency of trials and errors. Knowing what to do because of science is being smart; knowing what to do out of personal experience is sheer luck.

Experience drives you depending on various factors which you do not control... they may drive you to do exactly what is required in one situation or even many situations, but it all depends on how coherent the sample that constitute your experience is with reality as a whole. (Your life is effectively a sample of a population which regroups the experience of everyone, as well as experiences that could have occurred, but didn't)

If your experience fits the bill, you do not succeed out of genius or because you are smart... you simply were lucky, like the guy who earned his fortune with a lottery ticket.


The only way to be intentionally succeeding is to build knowledge and use it. It's also one of the very few things that should separate adults from children who do not have the biological luxury of being capable of formal reasoning, which includes the deductive reasoning which is required to find concrete applications to abstract ideas such as scientific theories.

well posted sir...applaud your patience as it exceeds mine.

[sureshs]

Originally Posted by 10isfreak

The contact lasts less than a fifth of a blink of an eye... that is, about 0,004 or 0,005 seconds. The ball doesn't even slide a millimeter, let alone spinning due to sliding.

It has been filmed to slide several inches along the strings, dragging the strings with it, and then the strings snapping back into the ball to produce spin.

Blink of an eye, millisecond, etc does not convey what is happening as it is beyond human intuition. A millisecond is a huge amount of time.

[Povl Carstensen]

I do not think the strings move several inches. More like, half an inch?

[Povl Carstensen]

Originally Posted by 10isfreak

My psychology teacher resumed the value of science in a few words. He said that psychology, as any scientific field, empowers its user with regard to some object of study. In that case, it grants the user power over himself and others.

Is the purpose of the science of psycology to get power over yourself and others?

Originally Posted by 10isfreak

In science, we do not happen to find stuff out of sheer luck... we devise systematic experiments to try and avoid the inefficiency of trials and errors. Knowing what to do because of science is being smart; knowing what to do out of personal experience is sheer luck.

Experience drives you depending on various factors which you do not control... they may drive you to do exactly what is required in one situation or even many situations, but it all depends on how coherent the sample that constitute your experience is with reality as a whole. (Your life is effectively a sample of a population which regroups the experience of everyone, as well as experiences that could have occurred, but didn't)

If your experience fits the bill, you do not succeed out of genius or because you are smart... you simply were lucky, like the guy who earned his fortune with a lottery ticket.

Experience is sheer luck? Not at all. Science is great, but experience is great teacher especially when feeding of imagination and intuition (neither being "luck"). Certainly it would be a dull and bland world with all science and no experience and fantasy and so on. But, a perhaps an easier world to have power over.

[Geology_Rocks!]

I wanna see this film.