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Andyzhao123
02-17-2018, 12:12 AM
Hi!
I'm looking around in tabletennisdb.com and I wonder what exactly throw angle is. Is it how high the arc is or how close to parallel the ball trajectory is to the racket?
Thanks for your time in helping me answer this question.

Simas
02-17-2018, 12:23 AM
It's how high the arc is. So high throw angle means that the ball tends to have higher trajectory and low throw angle means it will have the lower trajectory for the same stroke.

brokenball
02-17-2018, 04:06 AM
The term throw angle is bogus if you just want to measure the properties of a rubber.. It should be replaced by the ratio of the tangential to normal coefficient of restitution.
Arcs are determine by spin to speed ratio which is dependent on the stroke as well as the rubber. It is best to factor out the stroke or the player's ability and just judge the rubber properties.
If you look you will see every one has a different opinion about throw angle. That is because everyone has different strokes and abilities.

I would ask what is required for a high arc. Why would anybody want a high arc if it can be counter hit.
If I flat hit a ball it will have little if any arc. It makes no difference what rubber I am using,

langel
02-17-2018, 09:01 AM
I would ask what is required for a high arc. Why would anybody want a high arc if it can be counter hit.
If I flat hit a ball it will have little if any arc. It makes no difference what rubber I am using,

With flat hits only you will always use a very narrow window to pass over the net and land on the table, you will be unable to lift balls from under the table and return well cut balls.

How high arc a player needs is a subjective feel depending on his technics.
How high the arc of a bat will be depends not only by the rubber, but the wood too.
A stiffer wood will reduce the arc.

brokenball
02-17-2018, 09:28 PM
With flat hits only you will always use a very narrow window to pass over the net and land on the table, you will be unable to lift balls from under the table and return well cut balls.

Agreed but this is about throw angle not about when to or not to flat hit.



How high arc a player needs is a subjective feel depending on his technics.

Yes, so what is being "measured"? Is it rubber, blade or technique?



How high the arc of a bat will be depends not only by the rubber, but the wood too.
A stiffer wood will reduce the arc.
I have add the same "feeling". Whether it is accurate or not is the question.
Throw angle is increased when the tangential force is relatively high to the normal force.
Blades do not flex tangentially. I think the point you are making is that relatively stiffer and faster blades reduce the ratio of the tangential to normal force by increasing the normal force.

Faster equipment will tend to have a lower throw angle given the same stroke. So the question I have is what is best? I think it depends on how one plays. If playing closer to the table speed isn't as important as spin. When playing back from the table speed is most important because gravity will cause the ball to drop. In the end the player finds what works for him.

zeio
02-18-2018, 05:33 AM
Is it how high the arc is or how close to parallel the ball trajectory is to the racket?
Both. You can produce a high arc with a lobbing or fishing stroke by having an open racket angle where the ball bounces off the racket surface close to perpendicularly. So, precisely, throw angle is how close to parallel compared to the surface of the racket.

If a blade can flex(the technical term is deflect) in the direction normal to the impact, it can also flex in the direction tangential to the impact.

langel
02-18-2018, 11:12 AM
The OP may like to read this:

https://thoughtsontabletennis.wordpress.com/2015/09/07/throw-angle/

brokenball
02-19-2018, 02:36 AM
If a blade can flex(the technical term is deflect) in the direction normal to the impact, it can also flex in the direction tangential to the impact.
Has anybody been able to detect this? While I agree that this can happen and even steel will deflect, I seriously doubt the blade deflects tangentially enough to make a difference or even measure.

zeio
02-19-2018, 03:48 AM
Yes, at least one body has been able to detect this. It deflects tangentially enough to make a difference and even measure.

BTW, your writing style reminds me of someone whose name once starts with a p and ends with a y.

yogi_bear
02-19-2018, 03:57 AM
Dependes on high the arc is. Rubbers that have higher arc tend to give you more room vs mistakes when looping. Low arc loops have advantages for the attacker because it is harder to counter so it has advantages and disadvantages.

Der_Echte
02-19-2018, 05:51 AM
There are SO MANY FACTORS that affect the rebound it is silly to say this is gunna do that, but given a certain impact with one equipment and the same impact with another equipment, one can tell if the ball if flying off the bat higher or lower angle with that same impact vs the same incoming ball. You play long enough and with enough equipment you will know. Sorry, the experiments we can try to make by putting a bat in a vise and throwing a ball from a robot against it do not properly simulate what you need to do in a point.

How one accelerates the bat, how one holds the ball, how someone applies grip pressure before and during impact, and how they approach the ball have a lot of say in the output.

Grip pressure is also a very under-learned and under-utilized asset even among good amature players. Sure, "touch" is the change of grip for a slow, short ball, but the grip pressure used on blocks, short strokes, and full strokes has a huge affect on the output. A machine today will not ever get that aspect to measure it. Yet, a decent amature player can detect this almost right away. A pro player will know just about all there is to know within one rally sequence.

Der_Echte
02-19-2018, 05:58 AM
OP, as you can see, from all these answers, it is not such an easy thing and many different opinions.

However, one can make a little generalization of a blade's throw angle performance for simplicity by reducing it to how it performs on your one critical shot... often this is the counter topspin vs topspin of an opening slow/heavy loop vs an underspin ball.

A lower throw performance makes it easier to counter topspin a fast and heavy incoming topspin ball with control intuitively, but you have to lit or open blade or impact faster to make the loop vs underspin.

A higher throw performance makes it easier to control the opening heavy loop vs underspin, but makes you adjust to the incoming topspin ball if you are to counter loop it. You do that adjustment by a little softer grip pressure or a more forward swing... or the top secret way of impacting a little on the side for a hookshot.

langel
02-19-2018, 08:45 AM
Personal feel, techniques and style are most important, but all these come with experience and this experience means that the player has fond the proper synergy between the many factors of his play and the objective properties of his bat - wood and rubber.
This synergy is subjective so some aspects of the results may not refer to the feelings of other players.
But the objective properties are a good orientation for what you can expect from a wood, rubber and a setup.
You may see players playing both with high and low arcs using high-throw rubbers, but you will hardly see a decent high arc made with a low-throw rubber.
And something else - a high-throw with loops usually means low-throw with cuts and the opposite - low-throw with loops means high-throw with cuts.
If the rubber produces same arc with loops and cuts /provided the strokes are of same strength and same, but mirrored angles/ its throw is middle.
So one may use loops and cuts to determine the throw properties of a rubber, and the more experienced he is, the more objective his subjective feeleng will be.