Racket face angle not the same for a given height of the contact point???

Ok, the title is kinda confusing, let me explain it better:

Last weekend I was rallying back and forth with my friend using standard topspin rally shots. Then, in the middle of a rally, he hits a low-skidding slice. It was deep so I didn't have to move forward much. Anyway, I saw the slice and noticed that I would have to adjust to deal with a low ball. I've been handling quite a few low topspin balls during this practice session so I thought I will deal with this slice in a similar way. But, after hitting the ball and feeling a nice, solid contact, the ball ends up in the net!

So, I was thinking, for a given height of contact with the ball, if the ball was a backspin slice, my racket face at contact should be facing MORE UPWARD than if I was dealing with a topspin shot at the same contact height.

Now, here is my guess at why this is so. Recall some physics law that states that the angle of incidence equals the angle of reflection (whatever the law is called). Here is a pic for reference:
light_ill28.gif

So just imagine that bottom horizontal line representing your racketface.
Now, for a topspin shot that kicks up after the bounce, the "angle of incidence" would be larger than a slice that skids after the bounce. So if you return the skidding slice shot with the same racket face angle (relative to the ground) as returning a topspin shot, the "angle of reflection", which represents the initial trajectory of the ball right after contact, would be less for the returning the slice shot than for returning the topspin shot. Thus, when you return a slice shot like that, the ball would leave your racket on a much lower trajectory than you'd expect, and the ball would go into the net. Obviously, the stringbed and racket deform during contact so the effect descirbed above would be altered a bit, but what I described above is still a factor.

So basically what I'm saying is for slice shots, angle your racket higher (i.e. racket face more "open").
For topspin, close your racket face more. I find this especially true when I am hitting high kicking topspin shots on the rise. Referring to the above, the "angle of incidence" would be very large on those shots, so closing the racket face more to compensate would help me make my shot more like what I want.

Do you guys think my theory is right? I'm gonna try to apply it soon, especially on against slices, to see how it goes.
 

patrick922

Semi-Pro
wow good analysis. .wunderbar...i think you are right with the theory. but it doesnt have to be necessarily open... what i think of on low knifing shots is to get under the ball a much as possible, therefore creating like you said a more open racquet face.
 

alan-n

Professional
Yes but it applies to a small degree if you have a fast swing and strike the ball cleanly. You have to take into account that the swing path, swing speed, racquet face orientation can change slightly during contact, head flex, dwell time of ball..... and especially the spin of the ball into the racquet and off of it.

Again yes, you have to predict the angle of the ball coming into the racquet and execute the stroke to generate the desired shot. As for the angle of reflection, this is nearly non existent as you has you strike the ball cleanly with a racquet with enough mass behind it to crush / spin it along the stroke path.
 

brucie

Professional
Wow... thats 1 of teh most clever things iv heard in a good while! teh diagram is really useful too. Brings back old Science memories. lol thanks a lot
 

ceejay

Semi-Pro
I found using the diagram utterly confusing, but what you've written sounds okay.

Btw, its simply called the law of reflection.
 

kevhen

Hall of Fame
Yes, slice shots tend to come in low and go out low so you have to adjust and swing up more. Good analysis.

I thought this post was going to be about Wardlaw's directionals about when to change directions on the ball and how hitting back where you came is much easier than changing directions.
 

maverick1

Semi-Pro
I think we can disprove this incident angle theory by considering volleys. When you are at the net, you would agree that the opponent's topspin passing shots dip down and slices stay relatively flat. The theory would incorrectly predict that you have to angle the racket up for a topspin and down for a slice. Experience shows that this is not true. You need to volley up against a slice and down against a topspin.

The real reason has to do with the spin of the ball.

Just before the underspin ball makes contact with your strings, underspin rotation means that the near side of the ball is moving upwards and the back of the ball is moving downwards. When the ball makes contact, the strings stop the upward movement of the near side of the ball, but the rear of the ball continues to move downwards. The combined effect is to make the underspin ball take a downward turn after making contact. By similar reasoning, topspin balls tend to go up off the racket.

I hope this wasn't confusing.
 

kevhen

Hall of Fame
Vollies are different than groundstrokes. Slice after the bounce losses most of it's spin and may actually reverse spin and be spinning forward like topspin but it does come in at a different angle than topspin.
 

maverick1

Semi-Pro
kevhen said:
Vollies are different than groundstrokes. Slice after the bounce losses most of it's spin and may actually reverse spin.

OK, that is true. The bounce adds some topspin to the ball(for the exact reason I explained above, but with the court floor playing the role of the string bed) and if the initial spin was mild underspin, it can reverse to mild topspin.

But shots with mild spin don't require much adjustment and are pretty much irrelevant to the present discussion. What matters is that a topspin shot will have topspin after the bounce as well, and a heavy underspin shot will continue to have underspin after bounce.

So I think what I said above remains valid. The OP's explanation is an interesting effort but ultimately a red herring, IMO.
 

travlerajm

Talk Tennis Guru
The effect is magnified by the ball spin against the stringbed. When your opponent's shot has underspin, you need to aim higher on the volley to keep it from dumping into the net. And if your opponent's shot has heavy topspin, you need to close the racquet face to keep from popping the volley up in the air.

Having more mass in the hoop, or a tighter stringbed, will help reduce this effect.
 

joeyscl

Rookie
counterfeit25, I don't know if your theory is true or not. But I figured the same thing when I was watching people play tennis when I was 10 years old, even before i started playing tennis myself... It's not exactly rocket science is it?

...I only kept this in mind when i started out...i dont know if it helped me or not. Now i just do the things i feel most natural...
 

Bottle Rocket

Hall of Fame
maverick1 said:
The real reason has to do with the spin of the ball.

Just before the underspin ball makes contact with your strings, underspin rotation means that the near side of the ball is moving upwards and the back of the ball is moving downwards. When the ball makes contact, the strings stop the upward movement of the near side of the ball, but the rear of the ball continues to move downwards. The combined effect is to make the underspin ball take a downward turn after making contact. By similar reasoning, topspin balls tend to go up off the racket.

I hope this wasn't confusing.


I am so glad you made that post! Everyone totally overlooks this fact.

I often see someone hit a really great slice that someone tries to volley. The volley goes seemingly straight down into the net... The volley man gets mad at himself and thinks he did something terrible wrong. His volley technique was sound, he just didn't take into account the spin. The guy who hit the slice gets no credit.

I think this is one of the things that really seperates players. This applies to slices off the ground as well. If you can't process the shot coming at you and make the corrections needed, you're just not there yet.

I occasionally play someone that slices the crap out his backhands which usually land midcourt, they are not the skidding type. No matter how much I try to "get up" to the ball and get my feet right, I just never time it right and end up reaching. Lot's of things are at play here includig the bounce counterfeit25 is talking about as well as spins.

I think this thread is getting good.
 
maverick1 said:
Experience shows that this is not true. You need to volley up against a slice and down against a topspin.

Is this really true? My volleys suck so I wouldn't know, but if it's true thanks for the tip! =)

But the my theory works on groundstrokes since I just tried it today with good effect. Maybe you guys can debate on my explanation to the conclusion but my conclusion is correct (for ground strokes anyway).

Also, I found my theory (my conclusion, whatever) can apply to changing the horizontal direction of the ball (i.e. crosscourt rally to DTL, etc.). But for this case, I would have to consider that the racket kinda goes backwards at contact, depending on how heavy the incoming shot is and the way I am handling it (by "go backwards" I don't mean the racket flexes, I mean my wrist is forced into a more backward position due to the heaviness of the incoming ball). So, I will still have to think about that. Any input on this one would be helpful! =)
 

tennis_hand

Hall of Fame
basically you either open up the face more if it is very low, or swing up more, more vertically, and fast, if it is not too low but with a heft of backspin.

or you just slice back to counter the backspin of the ball, or create a slice drop shot.


These are the options according to physics. :)
 

shindemac

Hall of Fame
No, the theory and conclusion are wrong. What if the incoming angle is the same for a topspin and slice shot? Your theory would tell you to do the same thing and you would get the ball to go over the net and land in. Like many have said, that's not how spin works. And that's how many people get burned and make a mistake, because they think it's simplistic and don't account for the spin. Spin can be used as a weapon, and not just to get the ball in. If you adjust the amount of spin, the other player has to adapt and counter this spin which can be hard for many players.
 
shindemac said:
No, the theory and conclusion are wrong. What if the incoming angle is the same for a topspin and slice shot?

Ok, now I know spin plays an effect (most notably on volleys I guess). But my theory also covers the case when the incoming ball has the same spin but different incoming trajectory.

So, if my theory is "wrong", as you say, then consider returning a kick serve with 2 different cases: a) You return it on the rise at waist height. b) You return it on the drop at (the same) waist height.

So if my theory is "wrong" and has no significant effect on the way you handle an incoming ball, then your racket face angle should be the same in the 2 cases above, since both incoming balls have the same spin and you are contacting them at the same height.
Obviously, you shouldn't handle both of the cases with the same racket face angle on contact. You should close your racket face more when returning on the rise, and open your racket face more when returning on the drop. This coincides with my experience.

So, I would say my theory in the original post has an effect on the way you should handle an incoming ball, but it is not the *only* effect. Basically, what you should get out of my theory is that the trajectory of an incoming ball has an effect on the way you should deal with that ball.

Based on the other stuff I read in this thread about spins, here is what I would conclude:

-At contact, the more the ball is coming in on an "upward" angle (note this also implies "less downward"), the more you should close your racket.
-At contact, the more the ball is coming in on an "downward" angle (note this also implies "less upward"), the more you should open your racket.

-At contact, the more the ball is coming in with topspin (note this also implies less underspin), the more you should close your racket.
-At contact, the more the ball is coming in with undersping (note this also implies less topspin), the more you should open your racket.

Right?
 

maverick1

Semi-Pro
counterfeit25 said:
-At contact, the more the ball is coming in on an "upward" angle (note this also implies "less downward"), the more you should close your racket.
-At contact, the more the ball is coming in on an "downward" angle (note this also implies "less upward"), the more you should open your racket.

-At contact, the more the ball is coming in with topspin (note this also implies less underspin), the more you should close your racket.
-At contact, the more the ball is coming in with undersping (note this also implies less topspin), the more you should open your racket.

Right?

Right
 

shindemac

Hall of Fame
Your first theory was too simplistic. Your second theory is better because it accounts for spin. But I think anyone who's played ping pong would know this.

In the end, I'm not sure your theory is that helpful. You could end up with cases where you open up and then you have to close the racket face. That would confuse people. And now you have to factor in the amount of spin which is much harder to do. Also, you could hit the at the top of the bounce which is what most beginners do anyways. That would nullify any incoming angle non-sense.
 
shindemac said:
Your first theory was too simplistic. Your second theory is better because it accounts for spin. But I think anyone who's played ping pong would know this.

In the end, I'm not sure your theory is that helpful. You could end up with cases where you open up and then you have to close the racket face. That would confuse people. And now you have to factor in the amount of spin which is much harder to do. Also, you could hit the at the top of the bounce which is what most beginners do anyways. That would nullify any incoming angle non-sense.

So... you're saying what I'm saying is too confusing? Or incomplete?
Anyway, I don't think it's too confusing, but if you do, then just ignore it.
About my theory being incomplete, it is incomplete. I don't think it ever will be, but nevertheless it helps me (it already has), so I hope it can help as many other people as possible.

Again, any input is welcome imo =)
 

Mahboob Khan

Hall of Fame
To the original poster. I like your analysis and also your solution of the problem. I would like to add the following "mix" to your analysis:

When you are handling a sliced ball, the ball is rotating away from you, in other words, from your position, the rotation is similar to that of a topspin ball. Remember, when you impart topspin to the ball, the ball is rotating/topspinning away from you! Did I light a bulb? Thus, the sliced ball is suitable for your topspin response so that you will stay with the rotation of the ball. Yes, you need to get down to the level of the ball and return the ball via a "reverse forehand" when the strings are going more up on a vertical path than forward followthroughing on the hitting shoulder! In this situation, you do not need to open the racket face!!!
 
Mahboob Khan said:
Yes, you need to get down to the level of the ball and return the ball via a "reverse forehand" when the strings are going more up on a vertical path than forward followthroughing on the hitting shoulder! In this situation, you do not need to open the racket face!!!

Oh yea, now that you brought up the reverse forehand, I remember that I didn't have to open the racket face so much on that shot. But I mostly use a reverse forehand against a slice on passing shots, where the angle I would generate from the topspin is more important than pace. So now, I have one more thing to add:

-The more topspin you're generating from your stroke, the more closed (i.e. less open) your racket face.
-The more underspin you're generating from your stroke, the most open your racket face.

Thanks for the input!

metsjets said:
adjust so you can hit the ball over the net. don't think...

Yes, that applies during matchplay. But when I am practicing, the implementation of my theory is not second nature yet, so I have to conciously try to apply my theory (i.e. "think") during practice so that it becomes second nature, thus allowing me to not think about it when I play.
 

krprunitennis2

Professional
Spin from the slice.

Mahboob Khan said:
When you are handling a sliced ball, the ball is rotating away from you, in other words, from your position, the rotation is similar to that of a topspin ball.

I'm not sure if you're talking about hitting the ball before it bounces, but doesn't the ball do this?

spinafterslice.jpg


Ahh, I forgot to say...the ball is coming from the right happy face ball to the left happy face one. Sorreh.

I'm not sure if you'll get what I'm saying by this, but I tried this out with a tennis ball. Everytime I sliced it, it has topspin after the bounce. If it still has slice after the bounce, wouldn't the ball would have to keep bouncing towards the net instead?

But I'm not really sure about this so you guys see if this is right first.
 
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